# My Tool Grinder.



## BaronJ

Hi Guys,
I started talking about making a tool grinder in another thread so I thought it would be better to start a new one rather than clutter up someone else's. 

I have been collecting various bits and pieces for a while now.  But the other day I got to weld the motor mounting plate to the base plate.

Because the motor is a salvaged 1200 watt universal motor from an old rotary lawn mower and runs at a terrific speed I need to slow it down somewhat.  So I've also built a triac speed controller that I can use to vary the speed from a standstill to the maximum rpm.

The abrasive disc that I have acquired is rated at 5200 rpm so running it beyond that speed would be dangerous.

The photos show the various bits that I have completed so far.  The motor mounting plate is 6 mm steel plate.  I used a standard IEC socket and illuminated switch to supply power to the controller and then the motor.  A PCB was made to fit in the plastic box bottom with the triac and its heatsink attached by screws.  The speed control potentiometer is fastened through the PCB and box. Its mounting shaft and nut used to fasten the PCB to the bottom of the box.  The PCB is a single sided board with the components soldered directly to the copper.


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## Hopper

Looks like a good project. Keep us posted on your progress.


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## BaronJ

Hi Guys,

As promised some more pictures.
These show the motor and speed controller mounted on the frame.  There are some photos of the grinding wheel and the work support table.  Note non of this is set in stone yet as I need to make something to control the table.

As you can see from the marks on the grinding wheel I've given it a spin.  It put a lovely finish on a lathe tool.  I did not run the motor up much above 2000 rpm because there is some vibration that I think is the wheel that is slightly off balance.  Having said that, I haven't attempted to true up the wheel either.

Oh the curved bit of tin is a temporary guard to go over the wheel.  The wheel is only 1/4" thick and isn't really intended to be used on the side.


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## DJP

I had a need to sharpen end mills instead of buying new so I created a simple grinder from scraps in the shop. The motor runs at 3500 rpm and the cutter holder is made from HMW plastic. The screw with wing nut on the end limits cutter position and the diamond bit on the end is for wheel dressing. I created a sleeve to hold 3/8 inch shank cutters which covers most of my needs.

4 flute cutters are easily sharpened and only the centre needs to be relieved by hand on a bench grinder.

I kept my tool grinder simple because it gets so little use but it feels good to be able to have sharp tools when I need them.

Many of the steps in your project were the same for me.


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## BaronJ

Hi DJP,
I like the plastic jar lid used as a wheel guard.  I've been toying with using an underground drainage pipe joint to make a protective cover for the motor.  You get a nice tickle if your knuckle touches a brush holder when you go to adjust the speed control knob.

One of the criteria I had for mine was to be able to accurately grind lathe tools and sharpen drills with four facets.  Grinding slot drills and end mills hadn't occurred to me until you mentioned it.  I guess that I will need to obtain a dished wheel to do those.

The plastic/perspex parts are an adjustable removable table so that I can set up to grind thread cutting tools.  I have a lot of work to do to make the fittings for the drill grinding attachment.


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## DJP

A plastic motor cover makes good sense mostly to keep grinding dust out of the bearings. I have a simple plastic cover which is not in the picture but the motor needs air to stay cool so there are some trade offs. The plastic mayo jar lid captures dust more than providing safety protection. Working from the side of the cup wheel seems safe enough to me.

I learned to sharpen drill bits by hand and I do the same for lathe bits. A green wheel for carbide works well enough and I have made carbide insert holders which limit the amount of sharpening required. It was the milling cutters that were hard to sharpen by hand. One sharpened flute was usually was doing the work so I needed a cup wheel and jig to sharpen four flutes.

Your pictures of construction steps were so similar that I had to post. My (surplus) motor didn't have a capacitor so some electrical work was required. I turned an aluminium hub for the small metric shaft that would also hold the small cup wheel. I fussed with whether 3500 rpm was fast enough. It was.

This is one of those projects where the prototype is good enough to get the job done so I doubt that I'll build a better tool grinder like yours.


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## BaronJ

Hi DJP,



DJP said:


> A plastic motor cover makes good sense mostly to keep grinding dust out of the bearings. I have a simple plastic cover which is not in the picture but the motor needs air to stay cool so there are some trade offs. The plastic mayo jar lid captures dust more than providing safety protection. Working from the side of the cup wheel seems safe enough to me.



I agree with you about the motor cooling !  It would be nice to have a fan on the motor shaft blowing air over it.  I'll have to keep an eye on the temperature when I start to use it in anger.  I don't see any problem with using a cup wheel like you are doing.  My concern is that side pressure on my wheel which is only 1/4" inch thick, could cause the wheel to burst.  The other concern is failure of the Triac that is used to control the speed.  These like to fail short circuit !  If that happens the motor will take off at maximum rpm, about 26,000 rpm which is way over the safe 5200 rpm speed for my wheel.



> I learned to sharpen drill bits by hand and I do the same for lathe bits. A green wheel for carbide works well enough and I have made carbide insert holders which limit the amount of sharpening required. It was the milling cutters that were hard to sharpen by hand. One sharpened flute was usually was doing the work so I needed a cup wheel and jig to sharpen four flutes.



Whilst I can sharpen drills by hand, after a fashion, I really need to make a jig to help get them just right.  My eyesight isn't what it was either...



> Your pictures of construction steps were so similar that I had to post. My (surplus) motor didn't have a capacitor so some electrical work was required. I turned an aluminium hub for the small metric shaft that would also hold the small cup wheel. I fussed with whether 3500 rpm was fast enough. It was.
> 
> This is one of those projects where the prototype is good enough to get the job done so I doubt that I'll build a better tool grinder like yours.



I wouldn't say that mine is particularly brilliant !  Really just a means to an end.  Having a motor handy and some bits of 1/4" plate helped though. 

Any more pictures of your tool holder ?


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## DJP

Instead of a TriAC consider a fixed step down transformer or just a resistor in series. A household light bulb may work. Once you get a good speed for the tool there isn't much need to make it variable, in my opinion.

I'll take additional pictures for you of the tool holder. Consider it a T square that runs along the aluminium fence in front of the cup wheel. I cut one flute at a time then rotate the cutter in the holder and lock it down for the second cut, then third, then fourth cuts. It's a good set up as even if the T square doesn't follow the fence exactly on the first pass you can repeat until the wheel no longer cuts.

I saw a simpler holder which is just a square block with a hole in the middle to hold the milling cutter. The block is flipped in each side to cut each flute. You then only need an angled surface to run along. My sharpening angle is fixed at 12 degrees which isn't optimal but it works. 

Even though this was built from scraps and with many compromises, having sharp milling cutters is priceless.


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## DJP

Here is a better picture of the milling cutter holder. One end holds the milling cutter at a fixed depth and orientation to the wheel while the other end holds a diamond tipped tool used to dress the wheel. I used HMW plastic for this holder as it slides easily on a flat surface and against the fence. HMW plastic is strong enough for threaded bolts making it good for jigs.

I bored out the holder for 1/2 inch cutters and made an insert for 3/8 cutters. I may still make bushings for smaller sizes.

Hope this gives you some ideas for your project.


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## BaronJ

DJP said:


> Here is a better picture of the milling cutter holder. One end holds the milling cutter at a fixed depth and orientation to the wheel while the other end holds a diamond tipped tool used to dress the wheel. I used HMW plastic for this holder as it slides easily on a flat surface and against the fence. HMW plastic is strong enough for threaded bolts making it good for jigs.
> 
> I bored out the holder for 1/2 inch cutters and made an insert for 3/8 cutters. I may still make bushings for smaller sizes.
> 
> Hope this gives you some ideas for your project.



Thanks for the picture.  Yes it helps.  I've some plastic that would do that job just fine.  I'll have to have a play with some ideas.  That is when I can get some new gears for the mill...

I was slitting some aluminium plate earlier and suddenly the mill jammed for a fraction of a second and then suddenly ran free.  It has destroyed the driving gear from the motor.  After removing the gear I discovered that the spindle had a rough spot, so I stripped the gearbox down to find that the gear in there was not what it should be !  Right from new the machine sounded odd, but I let it carry on thinking that it was just a running in noise.  It appears that the twin gear was not machined properly or that the gear had swarf between the teeth.

Either way I'm now out of action with the mill until I can get new gears.  At the moment I'm inclined to throw the whole thing in the scrap bin.  Plastic gears have no use being in what should be good machines.  :rant::rant:


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## DJP

My first mill was a mini type with plastic gears. The circuit board is critical as it senses a spike in current to shut the machine down and save the gears from damage. Your circuit board may be defective. I was tempted to remove the circuit board and run the motor on DC but decided against it. Some have converted their mini mill to run off a belt and scrap the gear box entirely. That would be my preference but when I bought the machine I also bought a spare set of gears. With light use gear damage has not been a issue for me.

My second mill is an old Burke which is a heavy duty work horse. A Bridgeport is still the final solution. Someday.

If you had a working mill you could cut a new gear easily. I cut one for my wife's 45 year old Braun kitchen machine. The old gear is used to control the indexing of a shaft on which a gear blank is mounted.  A specially ground fly cutter was good enough to form the shape of each gear tooth. The resulting gear was noisy but it worked and I cut two more as spares. The kitchen machine is good for at least another 150 years.


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## goldstar31

If you have plastic, why not turn it to size and use your stripped gear as a template and use your lathe as a planer? Otherwise, put in pegs of plastic into the stripped teeth- and use a soldering iron hot to make new teeth. 

 The idea is from using PTFE candles to repair gouged ski bottoms.

 Regards

 N


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## BaronJ

goldstar31 said:


> If you have plastic, why not turn it to size and use your stripped gear as a template and use your lathe as a planer? Otherwise, put in pegs of plastic into the stripped teeth- and use a soldering iron hot to make new teeth.
> 
> The idea is from using PTFE candles to repair gouged ski bottoms.
> 
> Regards
> 
> N



Hi Guys,
Having calmed down now.   I agree that making new gears would be one way to go.  My inclination would be to use brass for both.  Having spoken to the supplier, they are going to send me a pair of new gears.  I did make a point of letting them know about the sand, grit and other debris in the gearbox, not that I think it will make any difference. :fan:

The third picture going down are pictures of the dual/duplex gear that sits in the two speed box and directly drives the spindle.  Difficult to see in the pictures but the small gear is actually machined off centre by about 50 thou (1.3 mm) whilst the large gear has not been used at all and the teeth are in good condition. 

I don't have a problem making a gear cutter for use on the lathe.  The hard part would be indexing to produce 61 and 41 teeth accurately for the dual gear and 36 helical teeth on the smaller one.  Now if I had a mill... :hDe:

Ah well !  Maybe next week.


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## BaronJ

Hi Guys,

Having looked around I have decided that it would be more cost effective in both money and time to replace the plastic dual gear with steel.

I found that I could buy suitable gears off the shelf quite economically direct from  a UK manufacturer.

The pictures are two of the gears that I bought to do the job.


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## DJP

There must be some reason that plastic was chosen for gears. By upgrading these two you may have just moved the problem to the next plastic gear in the set. I think that there are five gears in the package of spares that I purchased.

What about noise and lubrication? My old Southbend lathe has the gears exposed for easy oiling and they require some adjustment to ensure engagement doesn't generate noise. I am interested in how these issues are resolved for your project.

I still like the ideal of a belt from the motor to the spindle for quiet smooth operation and with a DC motor variable speed control is easy.

I have to admit that one reason for purchase of a spare set of plastic gears was to cut a steel or nylon set myself without losing use of the mill.


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## BaronJ

Hi DJP,



DJP said:


> There must be some reason that plastic was chosen for gears. By upgrading these two you may have just moved the problem to the next plastic gear in the set. I think that there are five gears in the package of spares that I purchased.



There are only two plastic gears in mine.  One small 38 tooth helical 7.5dg 1.25 mod and the duplex/dual gear which is 42 and 62 teeth 1 mod straight tooth which drives the steel spindle gear which is also a duplex/dual gear.



> What about noise and lubrication? My old Southbend lathe has the gears exposed for easy oiling and they require some adjustment to ensure engagement doesn't generate noise. I am interested in how these issues are resolved for your project.



I doubt that gear noise is going to be an issue !  Although that is the excuse that is given for the use of plastic gears.  My Myford lathe uses steel gears and makes very little noise at all.  Actually back gear is the most noisy.



> I still like the ideal of a belt from the motor to the spindle for quiet smooth operation and with a DC motor variable speed control is easy.



It wouldn't be too difficult to modify this mill for belt drive.  However it would be very difficult to remove the duplex gear without major surgery.  Its much more straight forward to do exactly what I am going to do by replacing the plastic duplex gear with a steel equivalent.   This also allows me the option of using the small helical plastic gear as a form of shear pin. 



> I have to admit that one reason for purchase of a spare set of plastic gears was to cut a steel or nylon set myself without losing use of the mill.



I don't know where you are but I was pleasantly surprised by how economical buying steel gears was, even to the point that they were available off the shelf.  OK I have to do some machining, but hey we are supposed to be "Experimental Engineers" are we not !


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## BaronJ

Well I got some work done on machining the bits for the new gears.

I made a plug gauge so that I got the brass sleeve bore right.  I also made a set of soft jaws to hold the gear so that I didn't damage the teeth whilst boring the centre out.  I've included a picture of the original gear assembly so you can see how it all fits together.


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## Swifty

I like your soft jaw setup, if I want to use soft jaws I will have to buy a new chuck, but I will keep your design in mind.

Paul.


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## goldstar31

Soft jaws. All that I do for a one off is to cut 3 bits of copper tube to put over the hard jaws and skim. 
I,m a lazy beggar and where I started off serious tool grinding was buy a cheap 6" Chinese or summation grinder, hoist the concrete abrasive wheels and replace them with decent white Aloxite ones. my first rests were wood but mark Two wa one of those cheap Taiwanese two way vices.which got the vice milled off and was replaced with a better tool holder. OK, I,ve got some vastly better stuff now but that was the start.
Let,s look at this tool grinding rationally. The first thing is grit. It gets everywhere. I made up one of those Worden things which got dumped because of grit binding the slides. My Quorn wa. One helluva thing to make but again it has felt grit excluders ans covers and is still a bloody nightmare!
My Clarkson and my little Stent suffere least. Arguably, the Kennet is the simplest and the easiest to set up. I was talking to Arnold Throp who had designed the adore part of DoreWestbury milling machine, had made a and described how he had made a Quorn in his Milling book. He used the little Kennet most times. I suppose like me.

I hope that the foregoing expands but does not detract was has been written earlier.

Norman


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## goldstar31

Apologies but this was written in some stately Scottish ruin on an unfamiliar iPad. 

,an ah that
Norman


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## Draw-Tech

BaronJ said:


> Hi DJP,
> 
> 
> 
> I agree with you about the motor cooling !  It would be nice to have a fan on the motor shaft blowing air over it.  I'll have to keep an eye on the temperature when I start to use it in anger.  I don't see any problem with using a cup wheel like you are doing.  My concern is that side pressure on my wheel which is only 1/4" inch thick, could cause the wheel to burst.  The other concern is failure of the Triac that is used to control the speed.  These like to fail short circuit !  If that happens the motor will take off at maximum rpm, about 26,000 rpm which is way over the safe 5200 rpm speed for my wheel.
> 
> 
> 
> Whilst I can sharpen drills by hand, after a fashion, I really need to make a jig to help get them just right.  My eyesight isn't what it was either...
> 
> 
> 
> I wouldn't say that mine is particularly brilliant !  Really just a means to an end.  Having a motor handy and some bits of 1/4" plate helped though.
> 
> Any more pictures of your tool holder ?


Hi Baronj
I like your idea, have been thinking of a grinder for years, (boxes full of dull end mills) anyway why dont you use a couple of gear belt pulleys and gear belt to slow your motor 4:1 will give you slower spindle speed and increase the torque, when I build my grinder I will mace the holder to fit my set of 3C lathe collets. just a thought. I will be watching your posts.
Jack
Draw-Tech


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## BaronJ

Hello Jack,
Most of the motors I have or can easily get my hands on are universal ones.  Even the washing machines today don't seem to use induction motors any more.
I believe that most if not all tumble dryers use an induction motor simply because they run at low speeds.  One motor that I have from one only runs at 850 rpm though it does have a 1/2" shaft.

But I'm afraid that until I can get the mill sorted those projects will have to take a back seat.

You mentioned collets.  I saw some in the local scrapyard the other day. About 1" diameter, maybe 2.5" long.  Next time I go I will have a look at them !  See what they are and if they are any good.


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## BaronJ

Swifty said:


> I like your soft jaw setup, if I want to use soft jaws I will have to buy a new chuck, but I will keep your design in mind.
> 
> Paul.



Hi Paul,
Its an old trick that I was shown many many years ago and one that I have used from time to time.  There is nothing special about them at all.  In fact the aluminium came from a belt drive gear that I had kicking around.  That is why it looks as if its got teeth.  The holding screws are 2 BA.  They are just bits sawn off a 50 mm long bolt with a hacksaw cut across the end.


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## BaronJ

goldstar31 said:


> Apologies but this was written in some stately Scottish ruin on an unfamiliar iPad.
> 
> ,an ah that
> Norman



Hi Norman,
Your wisdom is always welcome.   Ipad or not. :hDe:

And yes I agree about the dust from the grinding wheel !  Not only does it get everywhere but sticks to anything the slightest bit damp or greasy.  A dust extractor is called for.

Oh no...  Another round tuit.


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## BaronJ

Hi Guys,

Well I got some more done on the mill gears.  I also got the other gear that I was waiting for.  So I now have the pair for the primary drive from the motor.

I finished the brass bushing and got the gear pressed into place.  Put it into a pan of boiling water to heat it up first.  It pushed on quite nicely.  Put it back into the lathe and skimmed of the bit that protruded on the other side of the gear.  Turned it round. Clocked it up and found that it was spot on.  So I turned down the other end ready for the large gear.

Photos below.


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## goldstar31

Baron, 
         Thank you kindly. I wonder if I still have an unloved and maybe complete Quorn rusting away under a damp bench. I was jolted by the sad passing of Ron Chernich who made one.
Better looking than mine but mine certainly did what it was told. 
Will write again when I get back to some form of civilisation. Piss-instantly raining here in the Trossachs

Regards meantime
Norman


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## BaronJ

goldstar31 said:


> Baron,
> Thank you kindly. I wonder if I still have an unloved and maybe complete Quorn rusting away under a damp bench. I was jolted by the sad passing of Ron Chernich who made one.
> Better looking than mine but mine certainly did what it was told.
> Will write again when I get back to some form of civilisation. Piss-instantly raining here in the Trossachs
> 
> Regards meantime
> Norman



Hello Norman,

Yes I was saddened to hear about Ron's passing.  He was a nice guy who always tried to help, with good advice and a kind word or encouragement if you were stuck.

A Quorn... Rusting, unloved, under a damp bench...  Sacrilege !  Sacrilege I tell you.  You must love, care for and cherish it...  Or pass it on to someone who will. :hDe::hDe::hDe:

Sorry to hear that you have got our rain !  But I don't mind.  You can keep and make good use of it. :hDe::hDe::hDe:

Seriously though, I hope all is well with you both.  Take care.


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## BaronJ

Hi Guys,

Got a little more done.  Bored out the second of the two gears for the twin ones.
I've included pictures of the boring tool that I used and the stack of shims that go underneath it to get it to the correct hight.

I'll be glad when I get the QCTP that I started a while back, finished.  Its frustrating not having the mill working.

Also the intermediate shaft and gear that drives it.  This is one of the two stainless steel gears.  And now that the soft jaws are finished with a picture of those.


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## BaronJ

Hi All,

Well I've got a little further on and machined the small gear that fits onto the end of the motor shaft.  I've also discovered that this 10 mm diameter shaft has a 4 mm wide keyway slot.  All the others have 5 mm ones.

Pictures below.  One shows the arrangement of the two driving gears when assembled.  There are also pictures of the original bronze gear and the motor shaft.


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## DJP

Consider using a brass key or some other type of shear pin. Those steel gears look like serious business and any part failure will take place elsewhere in the machine. It could be more expensive to fix next time. 

My mini mill has a circuit board that shuts down the motor when there is a current spike. If you have the same feature then the brass key idea is secondary protection and maybe not required.

My thoughts for your consideration.


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## BaronJ

DJP said:


> Consider using a brass key or some other type of shear pin. Those steel gears look like serious business and any part failure will take place elsewhere in the machine. It could be more expensive to fix next time.
> 
> My mini mill has a circuit board that shuts down the motor when there is a current spike. If you have the same feature then the brass key idea is secondary protection and maybe not required.
> 
> My thoughts for your consideration.



Hi DJP,

Mmm !  I'd thought about that.  Those new gears will transmit an awful lot of power.  The question would be where to put a shear pin.  The ideal place I suppose would be in the second gear, the one driving the speed change spindle.  Because that one is the easiest place to get at.

I might be tempted to use a plastic key in that one.  I wonder how effective that might be.  I'm sure that some one here might know or at least where to look to get that sort of information.  I'll have to research that...

As far as I am aware there isn't any motor protection other than a fuse to protect it and the electronics.  I do have some 240 volt thermal overload trips that are adjustable between 2 and 10 amps but they take a two seconds or so to trip.  I could hit the stop button first !

When I first got the mill I took some current load readings and the mill only took a few hundred milliamp's off load and about 1.2 - 1.3 ampere taking a cut with a 12 mm cutter.  It seems to be the start up current that gets up to anywhere near the 8 amp fuse rating.


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## BaronJ

Hi All,

Well I got the large gear machined.  I put it in the four jaw using plastic shims to protect the teeth and then trued it up.  I bored it out to 0.940, cleaned it up.  It was a nice press fit onto the brass bushing.

All I have to do now is put in the 5 mm keyway slots. The motor keyway is 4 mm wide.  The brass should be fairly easy but the stainless steel will be much more difficult.


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## DJP

I think that gas powered lawn mowers have a key that sheers under the flywheel should the blade hit an construction. It saves the crankshaft. Outboard motors in the olden days had a small brass dowel instead of a key at the propeller shaft. It would shear to save the propeller from severe damage.

I only had one accident with my mini mill and it involved a fly cutter.  When it hit hard the power was immediately cut to the motor and there was no damage to the plastic gears. That circuit saved a big repair so I was thankful that it worked. My bigger and older Burke mill and Southbend lathe run on belts that will slip. So if faced with the repair you are doing, I'll change to belt driven instead.  

Making a key out of Delrin or HMW Plastic should work well.


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## BaronJ

Hi DJP,
The way this mill is constructed makes it very hard to do a belt conversion.  There is nothing above the spindle top bearing that you could use to attach a pulley.  I feel that replacing the gears is the only sensible way to go.

I will try a plastic shear pin by replacing the 4 mm key with a plastic one and see how that goes.  Since its just under the motor mounting plate, removing six M6 cap screws and the gear is immediately accessible.


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## BaronJ

Hi All,
I didn't get too much done today.  Hospital appointments got in the way.

The previous threads discussing shear pins and the like got me thinking about the security of the dual gear inside the main casting and how difficult it is to get access to it once the mill is re-assembled.

I'm conscious of the possibility of the gears slipping on the brass bush and then failing to provide drive.  In order to prevent any possibility of a gear coming loose   on the brass bush I have decided to pin the gears to the bush.

I used a 4 mm slot drill and drilled holes opposite each other on the joint line between the brass and steel.  I was very careful not to drill right through the gear.  I then tapped the holes 2 BA and inserted 1/8" inch by 2 BA hex socket grub screws.  Now there is no way that the gears can slip on the brass bush.  I've only had time to do one side today.

Note.  Looking at the photographs you can see how the brass has distorted slightly when threaded whilst the steel hasn't.


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## goldstar31

Baron,
            Hope your hospital visit went well. Workshops are getting to be memories now.
 Got the wiring done- after the 'Gas man cometh' with apologies to Flanders and Swann.

 Regards

 Norman


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## BaronJ

goldstar31 said:


> Baron,
> Hope your hospital visit went well. Workshops are getting to be memories now.
> Got the wiring done- after the 'Gas man cometh' with apologies to Flanders and Swann.
> 
> Regards
> 
> Norman



Hi Norman,
Its getting very frustrating   No one wants to commit themselves to a firm diagnosis.  They want to run some more tests and have me take a CT scan.  I've to go for the vampire on Monday morning for more blood tests.  I've been told not to book any holidays.  About the only thing that seems to be sure is the amount of time and passing around that is taking place.

Gears: !
Anyway I got the other side of the dual gear drilled, tapped and pinned this afternoon.  I just have to figure out how I'm going to put keyways into the brass bush and the motor spindle gear.

I'm toying with the idea of putting some kind of lubrication system into the mill head so that I can ensure that the gears get properly lubricated.  The original grease that was stuffed in, apparently, was intended to lubricate the plastic to metal tooth contact.  I've cleaned all that gunk out along with bits of sand and metal shavings.  Probably from when the casting was machined.  I've also discovered that at one point the casting has been ground away and welded to fill in or otherwise repair a bad casting.

The more I dig into this machine the less enamoured I become.


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## goldstar31

Baron,
           Be positive. Whatever your present thoughts, they can do great things that only a year or two ago, t were  impossible. 

 As for lubrication of mills, the only way forward is for you to strip out and clean and then re-grease. 

 I hope all is well. To hell with a bit of sand, eh?

 Norman


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## Griffin

Baron

 I agree with Goldstar, be positive, I too have been in that situation, still go every 6 weeks, vampires next week, GP can't keep up lol, and I have four consultants for the past 5 years, but today I cut my first backgear for the lathe, was so chuffed it actually worked, and that was out of polypropylene, next one is going to be a 77 tooth gear when I get the material for it, its taken me 4 weeks to get to this stage. I hope all is well soon, I always keep an eye out for your and other posts like it, it never fails to intrest me.

 Mark


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## BaronJ

Thanks, Norman, Mark,

Sorry about having a chelp about my frustration.  It is just getting passed around and nobody seems able to make a decision.  Anyway thankyou both for your kind words.

Mark,
Congratulations !  Cutting gears is anything but easy or straightforward as I'm sure Norman will agree.  I wonder if your next one is also going to be polypropylene or are you going to try steel or cast iron ?  Either way cutting your first gear is an achievement that you should be proud of.

Norman,
Once this mill is re-assembled there is no way I'm going to take it apart again just to lubricate the gears.

I'm considering drilling a hole in the side of the casting and fitting an oil nipple with some internal pipe to distribute lubrication to the gears...

See next post.


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## BaronJ

Hi All,
I've now got all the gears slotted and keyways done.  Apart from the lubrication considerations all I need to do now is put everything back together.

The photographs show the gears and the assembly as it would be inside the head casting.


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## goldstar31

BaronJ said:


> Why, why, Oh Why my, my battle stained weary champion?
> 
> I recall the late George Thomas who had bright, shiny and unoiled gear teeth. Or so he said:hDe:
> What is needed is lubricating grease on the bearings but if you think about carefully, the grease in your car's wheel bearings has been in place- unchanged, forgotten and ignored--- and is still doing rather well.
> 
> My lubricating oil has been pumping about =sheeesh= for nearly 8 and a half-decades. It's thin, gets cold and all that sort of thing but you get the idea.
> 
> I was having a bit of a giggle with a bloke from what was the generating board- a million years ago. The oil in the turbines had been in since Joseph Swan made his first light bulb:wall:
> 
> Concentrate on YOUR lubricating system.
> 
> Meantime,
> cheers from a moonbeam from the Lesser Lunacy.


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## BaronJ

Thank you Norman for those kind words of wisdom.

I shall try my best.    I promise.


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## BaronJ

Well I got everything put back together !  It runs nicely.  The repetitive chugging has gone.  It doesn't sound any more noisy than it did before but then again there isn't any load on the motor.

Back to doing what I was doing before the problems began.

Thanks to all for the good advice.


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## Griffin

Baron

 Not tried any metal gears yet, just concentrating on getting it right with the plastic, I think acetal is the stuff I'm going after or delrin if that works?, certainly not making any more out of polypropylene , hell they make supermarket bags out of it, only tried it as an experiment but it was still whizzing round today, still don't believe that? 

 The reason I'm doing this is I need the gear train for cutting a 10 TPI thread bar for the cross slide and compound slide, when I get round to making it, on a metric machine, and these gears give me an accuracy of 
 0.0000787 in :wall:Hell I can't even say that in words :fan:anyway I think its near enough, lol

 After that I want to get into making an epicyclic gear train to fit on the lathe motor for some proper gear reduction, have very limited space you see


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## robcas631

Baron,

I like how you used the Aluminum gears as cushions on your chuck.


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## robcas631

Norman,

Good idea. I have been reluctant to add any type of cushion because it might set my work off center.


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## goldstar31

robcas631 said:


> Norman,
> 
> Good idea. I have been reluctant to add any type of cushion because it might set my work off center.


 
 Glad to help. I'm a bit fed up. There are more pressing matters in our lives.
 I'm more or less taking a break until October. Perhaps 'Spending our Children's Inheritance ' summarises it.

 I bid you both well.

 Norman


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## BaronJ

robcas631 said:


> Baron,
> 
> I like how you used the Aluminum gears as cushions on your chuck.



Hi Rob,

They were just slices parted off from a 150 mm long aluminium gear used to drive a cogged belt.  It turned out to be just the right size to make those soft jaws.  If you ever need to turn something accurately concentric then that is one way to do it.  Even an old and badly worn chuck can produce very close work using soft jaws.


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## bazmak

Just read this thread with great interest,along with tramming the head,its
the reasons i bought a fixed column mill with belt drive.I also like the soft jaw idea.Also a thought.is that Myford use 2 tufnol gears for the tumbler reverse
to act as sacrificial gear and for reducing noise.Expensive,so i feel that the the
nylon key is the best answer or alum? Regards barry


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## gus

Hi Guys,

Been thinking about salvaging the cheapy umpteen M.I.C. end mills to mill aluminium. 
While milling the cams out of Sliver Steel, two MIC end mills went dulled. Had to buy Tungsten Carbide End Mills. I have a domestic sewing machine motor. Please advise is this adequate.


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## DJP

Any small motor should work as long as you can get the cup wheel RPM high enough. I found a small motor running at 3500 rpm and it works just fine to sharpen end mills. Two flutes are easy but 4 four flutes tricky as you still need to relieve the centre portion of the end mill on a standard grinder.

My philosophy is that any sharpening is better than no sharpening. The flutes don't need to be perfect and matched for the cutter to work just fine. At least for my level of machining, this approach works.


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## bazmak

I have also been thinking of a simple tool grinder for end mills etc
Anything must be better than by hand.My thoughts are to hold the cup wheel
in a mandrel in a collet on the lathe,i know the pitfallss???
Avoid dry grinding dust on the lathe.Adequate protection on the ways
Is 2500rpm fast enough for light cuts
Any thoughts on tool holding and setting compound angles
Still thinking.Diamond wheel or white carborundrem for HSS ?? Regards barry


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## Swifty

Hi Barry, definitely carborundum for HSS. Diamond wheels should only be used on carbide.

Paul.


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## BaronJ

Hi Guys,

I used a universal motor and a speed controller for mine.  A five inch (125 mm) diameter wheel needs around 3000 rpm whilst a 2 inch (50 mm) diameter wheel needs nearer 5000 rpm.  Its getting the surface speed up so that the wheel does't load up with removed material.

Of course since a universal motor often runs at very much higher speeds than is needed or safe for any particular wheel some form of speed control is required. The motor that I used came from an old rotary lawn mower and off load easily hits 20K rpm.  Its also 1.5 Hp so its way overkill for the job. 

A two pole induction motor on 50 Hz will run at 2850 rpm so using a belt and pulley drive will allow for speed control.  A larger pulley on the motor will allow the wheel spindle to be made so that it has a higher speed.

Since you are not removing large amounts of material the motor doesn't need to be very powerful so, Gus, your sewing machine motor might be just fine.

I agree with Paul, I wouldn't use a diamond wheel on HSS although you could !
They are more useful for carbide tipped tools and inserts.

HTH.


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## DJP

Here is my simple end mill sharpener.


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## gus

Hi DJP,

Please advise wheel type,O.D.,speed and motor HP. I am eyeing at DIY Tool Post Grinder type to touch up those umpteem M.I.C. end mills collected since 2004. Even though I have switched over to Taiwanese,Japanese and Indian end mills, the day will come for regrinding.


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## DJP

The motor says 100 watts on the label and it runs at 3450 rpm. A 20 uf capacitor is required to start it. I found it at a surplus store called Princess Auto in Canada for $10. The grinding wheel is the cup type that can be sharpened to a fine edge which you need for clearance when grinding 4 flute end mills. They were used so only about 2 or 3 inches in diameter. They are rated at 3800 rpm. A buddy gave them to me but I'm sure that they can be sourced at an industrial supply company like KBC tools. The only machining required was to build an aluminium mandrel for the stone that fit the motor shaft and the grinding wheel diameter. The motor shaft had a threaded section for a retaining nut.

The end mill holder is set at 12 degrees so nothing fancy when sharpening for various metals is possible. This hasn't been a problem for me. The other end of the milling cutter holder has a diamond bit that I use to reshape the stone cup wheel. Both the end mill cutting and diamond dressing follow the straight edge fence mounted just in front of the motor.

I built this set up as a prototype but it worked so well that after sharpening all of my collection of dull cutters I decided that it was good enough for the volume of sharpening that I need.


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## gus

DJP said:


> The motor says 100 watts on the label and it runs at 3450 rpm. A 20 uf capacitor is required to start it. I found it at a surplus store called Princess Auto in Canada for $10. The grinding wheel is the cup type that can be sharpened to a fine edge which you need for clearance when grinding 4 flute end mills. They were used so only about 2 or 3 inches in diameter. They are rated at 3800 rpm. A buddy gave them to me but I'm sure that they can be sourced at an industrial supply company like KBC tools. The only machining required was to build an aluminium mandrel for the stone that fit the motor shaft and the grinding wheel diameter. The motor shaft had a threaded section for a retaining nut.
> 
> The end mill holder is set at 12 degrees so nothing fancy when sharpening for various metals is possible. This hasn't been a problem for me. The other end of the milling cutter holder has a diamond bit that I use to reshape the stone cup wheel. Both the end mill cutting and diamond dressing follow the straight edge fence mounted just in front of the motor.
> 
> I built this set up as a prototype but it worked so well that after sharpening all of my collection of dull cutters I decided that it was good enough for the volume of sharpening that I need.




Hi DJP

Thanks for the info. My surplus sewing machine motor is rated 120 watts.
Plan to DIY a Tool Post Grinder cum End Mill Grinder.
Been busy making DIY Timber Casing to hold Mikes and Vernier Calipers etc.


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## gus

Hi DJP,

Please advise vender for the cup wheels.


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## DJP

The used cup wheels that I have are missing labels but if I had to buy new ones I would source Carborundum Gold Type 11 (Flaring cup). They look similar but mine are smaller (worn out). I also have some cup wheels made in Germany but there seems to be no standard for the centre hole. I'll probably look for wheels with the same diameter hole when it comes time to replace the ones in use as I turned a custom mandrel to hold the cup wheel and fit the motor shaft.

I expect my old cup wheels to last a long time if I only use them for sharpening end mills. That's another reason that my prototype grinder is not being made into a production duty set up.


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