# NYLON MILLING MACHINE GEARS



## Brian Rupnow (Jan 8, 2022)

I have a little story to tell. I have a CX601 milling machine from Busy Bee Tools and I love it. This milling machine does everything I want, except drill 1" holes in aluminum. I don't do that very often, but when I do, it's mostly ornamental holes thru flywheel webs. And this is the point where my mill lets me down. There is a nylon compound gear in the gear-head, and it lets you put the mill into the equivalent of "back-gear" on a lathe. About every two or three years, this compound nylon gear manages to strip all the teeth of one side. It costs around $70 for a new gear, and it's a royal pain to take the mill apart and replace the bad gear. It doesn't happen all at once. When it first decides to eat that gear, it jumps out of gear into neutral. If you can spare a hand to hold it in gear, it works just fine, but sometimes I run out of hands to do that. It doesn't take much force to hold it in gear, and I'm sure that if it was held firmly in gear so that it couldn't jump out, then it wouldn't wreck the gear. So, today I'm designing a third hand to hold the mill in "back gear" while I drill large holes. In the pictures, you will see a side view of my mill where the gear selector knob is, another picture that shows my "third hand" in position, and in the third picture you can see a bad nylon gear and it's replacement good nylon gear.


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## Brian Rupnow (Jan 8, 2022)

And here you can see a 3D model of my milling machine with the knew "third hand" installed and a detail of the 3/4" thick third hand. The 1/2" diameter knurled steel pin screws thru the arm and is captured behind the sheet metal enclosure that houses the motor. This sheet metal housing is quite "beefy" and should easily be able to counteract any forces that try to shift the gear selector out of gear. To put the machine into it's normal gear, you just unscrew the threaded pin enough that it no longer is held captive behind the steel motor housing.


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## mayhugh1 (Jan 8, 2022)

Why not make a replacement aluminum gear? It looks like a pair of pinned-together spur gears would do the trick. - Terry


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## Brian Rupnow (Jan 8, 2022)

My gear cutters are 24 dp. The gears from the mill are larger and probably metric.


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## RonGinger (Jan 8, 2022)

Grind a fly cutter bit to the shape you need. Then cut metal gears. If you don't have an index head use the plastic gear as a guide.


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## johwen (Jan 9, 2022)

I have the same Mill here in Australia Original lasted about two years and then stripped likewise the second did the same.  I haven't bothered replacing same for two years now I just use the mill on high gear. I have thought of making a metal gear next time but would have to remove the gear and assemble head to make the gear and then dismantle again to to put in the new gear. Maybe I could ask you if you could give me the OD of the gear and Number of teeth and pressure angle I could make same before I strip the box down. Also the thickness. I would appreciate your help if you would. The mill does a great job and is quite accurate. My mill is brand name WEISS Machinery Co. LTD Thank You John


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## phred (Jan 9, 2022)

I have the same mill, also in Oz,  branded Optimum, it has metal gears in that position. The only problem I've had is a motor controller failing but that was easily replaced. I suspect the gears are module 1.
Cheers, Fred.


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## Carbuilder (Jan 9, 2022)

Simple but very cool solution. As to making a metal gear to replace the nylon one...well...the nylon one seems to be the weak link now. If you replace it with something stronger, maybe you find the next weak link and it could be something more serious?


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## Bentwings (Jan 9, 2022)

mayhugh1 said:


> Why not make a replacement aluminum gear? It looks like a pair of pinned-together spur gears would do the trick. - Terry’s was going to suggest the sam thing. Doing som internet shopping you may be able to come up with the right gears and just pin them together. A couple of dowel pins to positive locate them then maybe some small flat head screws to more or less permanent hold them together. A long time ago I repaired a tool room lathe this way it worked perfectly untill one of the guys insisted on making a rediculously large part with heavy interrupted cut.  It finally broke the spindle shaft. Which turned out to be unobtanium so we had to make a new one  . I think each one of us in the tool room had a hand in making the new one . That old lathe is still running as far as I know. Wish it was mine.
> Good luck
> 
> byron


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## Bentwings (Jan 9, 2022)

Sorry for the spelling and context. I just got a new stylus and it take getting used to . It replaced my giant fingers on this iPhone


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## Brian Rupnow (Jan 9, 2022)

My mill was made in China, so odds are pretty good that the gears are metric. I can put up a drawing with all the dimensions.  I have only 24DP gear cutters, and don't want to fool around trying to make a single point cutter to match these gears.


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## Bentwings (Jan 9, 2022)

Brian Rupnow said:


> My mill was made in China, so odds are pretty good that the gears are metric. I can put up a drawing with all the dimensions.  I have only 24DP gear cutters, and don't want to fool around trying to make a single point cutter to match these gears.


There are man site devoted to gear both metal and plastic 
McMaster Carr has gears bu they are rather expensive . You could get exactly why you need . I buy odds and end from them. Very good service fast shipping 
Byron


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## Brian Rupnow (Jan 9, 2022)

This is the shape of the nylon gear I currently have. The tooth form is an approximation
The gears are measured with a Vernier caliper.


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## Jasonb (Jan 9, 2022)

They are MOD 1.5 20deg pa


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## Brian Rupnow (Jan 9, 2022)

All right!!! You fellows have convinced me. Time to make a raid on the Rupnow Fortune and buy Three annular cutters, a 1", a 15/16" and a 7/8". These things come with a 3/4" shank, and I don't have any R8 collets that are big enough, so I will buy 3 dedicated R8 collets which will take a tool with a 3/4" shank. I will still go ahead and fabricate the aluminum arm which will prevent the mill from jumping out of gear when in low range under heavy load. Thank you for your help.---Brian


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## Brian Rupnow (Jan 9, 2022)

Jason B--thank you for that information.---Brian


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## Gordon (Jan 9, 2022)

Involute gear cutters are not too expensive from Banggood and aiexpress if you can wait for the shipping. I have used the MOD cutters to cut DP gears without any problem for the type of things we use them for.









						9.8US $ |Livter M1 M1.25 M1.5 M1.75 M2 M2.25 M2.5 M2.75 M3 Modulus PA20 degrees NO.1 NO.8 8pcs/set HSS Gear Milling cutter Free shipping|Milling Cutter|   - AliExpress
					

Smarter Shopping, Better Living!  Aliexpress.com




					www.aliexpress.com


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## Gordon (Jan 9, 2022)

Another option is to male your own gear hob. Not hard to do.






						Zahnräder fräsen mit dem Gear Hobber
					






					www.metallmodellbau.de


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## Bentwings (Jan 9, 2022)

Brian Rupnow said:


> This is the shape of the nylon gear I currently have. The tooth form is an approximation
> The gears are measured with a Vernier caliper.


McMaster Carr has plastic gea 56 an 30 tooth metric 

ye cheap probably ost more for postage
I just got some I ordered based on bill of Métis from another site. Wrong size so I’ll let you chose based on your measurements I think you could pin and use flat head screws o hold them together

I’m working on a transmission with. Cluster gear so that’s what I’ll do.  You can get just about any screw o fastener from hem. Micro fastens has even smaller fasteners need. I’ve bough hundreds of screws and fastened over  years from both. We have some grizzly machines so we get stuff from hem too. Sometimes they ship good some times it takes for be our rotary table has been on order and paid for  over 3 months now I could really use it shortly 

grainger is another supplier we purchase from they have been pretty good too.


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## Ghosty (Jan 9, 2022)

Bentwings said:


> McMaster Carr has plastic gea 56 an 30 tooth metric
> 
> ye cheap probably ost more for postage
> I just got some I ordered based on bill of Métis from another site. Wrong size so I’ll let you chose based on your measurements I think you could pin and use flat head screws o hold them together
> ...


McMaster don't post out of the USA, have tried, so has Brian.
Cheers

Andrew


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## johwen (Jan 9, 2022)

Thanks Brian for the drawing. I will set about making an Aluminum gear set. The OD of each gear is calculated as follows 31 teeth plus2 by the module 1.5 give  OD for the smaller gear 49.5mm and the larger gear 87mm. I will make smaller gear with the hub spigoted into the larger gear and locktited then 3 dowels at the joint of the gear and spigot Cheers John


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## phred (Jan 10, 2022)

just finished a 80 tooth mod 1 in al.


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## Nikhil Bhale (Jan 10, 2022)

Hi Mr. Brian,
I like the Z axis handwheel for your mill with chain and sprocket drive.
Did it came as factory fitted with the mill or you made it?

I have a similar Sieg SX 2.7 mill with Z axis handwheel at top. 

regards
Nikhil


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## Iampappabear (Jan 10, 2022)

Miami could also be an option, I have often seen McMaster referenced but never Misumi.  Their part selection can be a little daunting as they offer so many options but their products are usually good quality and prices reasonable.


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## Brian Rupnow (Jan 10, 2022)

Nikhill I made that. I have a torn rotator cuff in my right shoulder that can't be fixed, so it hurts me to reach up to turn that top handwheel. So---I moved the handwheel down to a comfortable height to reach and then ran a bicycle chain up to the top.---Brian


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## Brian Rupnow (Jan 10, 2022)

Johwen--I hope that works for you. let me know how it turns out.---Brian


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## awake (Jan 10, 2022)

If I'm understanding the problem correctly, the real issue is that the mill wants to slip out of "back gear" while under heavy pressure. I would think that this is likely to tear up any gear, nylon or metal.

What is "supposed" to keep it in the low gear setting? Is there a detent of some sort? If not ... Brian's solution may be needed even with aluminum replacement gears.


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## Richard Hed (Jan 11, 2022)

Brian Rupnow said:


> Nikhill I made that. I have a torn rotator cuff in my right shoulder that can't be fixed, so it hurts me to reach up to turn that top handwheel. So---I moved the handwheel down to a comfortable height to reach and then ran a bicycle chain up to the top.---Brian


When you say "rotator cuff", is it bone or flesh?  I had ripped ligaments which were healed by use of accupuncture.  You might consult a puncturist if hyou can find one.


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## Brian Rupnow (Jan 11, 2022)

Richard--Mostly caused by being old and doing a lot of work over 75 years. I have used acupuncture for nerve related issues in my left leg and arm and it was very successful when nothing else would work.--Brian


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## Drawfiler (Jan 12, 2022)

I anyone wants a set of gears for this or any other application, I can hob them for you and post worldwide.
Peter


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## Richard Hed (Jan 12, 2022)

Drawfiler said:


> I anyone wants a set of gears for this or any other application, I can hob them for you and post worldwide.
> Peter


I have a plastic gear on a lathe that destructed, however, the makers put an extra in the kit.  I will eventually make one myself.  They are not that difficult if one has the necessary tools.


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## Peter Twissell (Jan 12, 2022)

Richard Hed said:


> When you say "rotator cuff", is it bone or flesh?  I had ripped ligaments which were healed by use of accupuncture.  You might consult a puncturist if hyou can find one.


The rotator cuff is the set of ligaments which holds the shoulder joint together.
I damaged one of mine by picking up my 260kg motorcycle in an angry hurry when I had dropped it in the car park at work.
It took about 9 months and some physiotherapy to sort it out.


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## Richard Hed (Jan 12, 2022)

Peter Twissell said:


> The rotator cuff is the set of ligaments which holds the shoulder joint together.
> I damaged one of mine by picking up my 260kg motorcycle in an angry hurry when I had dropped it in the car park at work.
> It took about 9 months and some physiotherapy to sort it out.


I don't know how I did mine but both shoulders hurt so much, hurt as much as a kidney stone.  Could not raise my arms at all.  Went to the butchers--oops, I mean doctor's, and found out that it would cost 9000$ in 2001 dollars to fix it and it may make it worse.  All I heard was " make it worse".  so I lookt in Moses Lake for a pucturist.  Found one, a Korean.  He punct a single needle in my ankle bone two days in a row.  Two weeks later, it was completely healed.  And look at me today:  I can raise my hands above my head.  As the say in Cambodia:  Lud dai twai preh, (raise hand praise god).


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## dnalot (Jan 12, 2022)

Richard Hed said:


> And look at me today: I can raise my hands above my head



I would like to see that. I have wondered if your species has the same number of fingers as we humans. And what are you doing up at 2:10 AM Richard?

Mark T


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## Brian Rupnow (Jan 12, 2022)

The three R8 shanks came yesterday. The other two annular cutters are supposed to come later this week. they surely look "spiffy".


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## Richard Hed (Jan 12, 2022)

dnalot said:


> I would like to see that. I have wondered if your species has the same number of fingers as we humans. And what are you doing up at 2:10 AM Richard?
> 
> Mark T


We have six fingers--we are specially bred so that we can play better piano than humans.  I usually don't go to bed before 2:00 AM


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## petertha (Jan 12, 2022)

I'm curious why you opted for what looks to be an end mill holder vs the annular cutter holder. I'm actually not sure why the Weldon has 2 retention screws for 90-deg faces. But it has the provisions for the spring/pin assembly up in the attic which the EM holders don't. BTW I also have an MT3 version for use in lathe tailstock.


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## Jasonb (Jan 12, 2022)

Quite a few of the cutters have two flats hence the two screws on the holders specifically for them


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## Brian Rupnow (Jan 12, 2022)

My bad Jason.--I made a mistake, and only realized it about an hour ago when I tried to put one of the annular cutters into the collets I had ordered. YIPES!!! it didn't work. I just reboxed the three collets I ordered and am sending them back to amazon. I ordered one of the correct collets that work with these cutters. Should come out money ahead because three of the collets I ordered cost $93. I've decided I can live with one collet and change the annular cutters as I need them, and one of the right kind of collet costs $75---Brian


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## Brian Rupnow (Jan 13, 2022)

So, after a bit of confusion (on my part), the wrong R8 collets have been returned and the correct R8 collet to hold these 3/4" Weldon shank annular cutters has been received, mounted in my mill, and a hole cut thru 1" aluminum plate. The "core" that is cut from the plate is setting on top of the plate. The hole was cut in "Low range" at 300 rpm. with lots of squirt on cutting oil. I did get the "birds-nest" of aluminum swarf which has been cleared away to take this picture. They make a beautiful smooth cut, and the milling machine doesn't sound like it is working very hard to make the hole. I am very satisfied.  The annular cutters cost about $30 each. I may buy a couple more different sizes---don't know yet.


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## Drawfiler (Jan 14, 2022)

Brian, do I see a horribly chewed up plastic gear in the first photo?
Peter


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## Jasonb (Jan 14, 2022)

Peter, look at the first page, first post of the thread and you will see the gear and the reason why it strips


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## Drawfiler (Jan 14, 2022)

I understand that, thats why I have made substitute gears in metal.


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## Brian Rupnow (Jan 14, 2022)

drawfiler--Yes you do. That's what this thread is about????


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## Brian Rupnow (Jan 14, 2022)

I couldn't figure out why the correct R8 holder for these annular cutters cost $75, while a standard R8 holder for a 3/4" drill was only $31. Now that I have the parts here, I see that there is a spring and a snap ring inside the correct R8 holder that lets a centering-pin retract into the body of the holder as the annular cutter passes thru the plate you are cutting. The centering pin then becomes spring loaded and pushes the "slug" out of the annular cutter after your cut so you don't have to fish for it with a pair of pliers. You can see the end of the centering pin sticking out past the face of the cutter. You can also see a centering pin setting beside the cutter---I made that one .001" undersize, which normally wouldn't matter, but in this case the pointy end is cantilevered out so far from where it is held that with 0.001" undersize it wobbled all over the place---Not what you want for centering.


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## Bentwings (Sep 1, 2022)

Ghosty said:


> McMaster don't post out of the USA, have tried, so has Brian.
> Cheers
> 
> Andrew




How about having a gear 3D metal printed ? Maybe a couple   You may have to search the country but I’m sure there are metal printing services there


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## Drawfiler (Sep 2, 2022)

These are made in plastic to deaden noise and vibration and work OK a until the day of the inevitable smash up when using a large cutter.
I have made replacements in both metal and Acetal (Delrin) with good results so message me if I can help


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## jumps4 (Sep 2, 2022)

Hello Brian and others
Little machine shop (littlemachineshop.com) carries metal replacement gears and parts for many of these import lathes and mills.
  It may be worth a look. You can call them by phone also.
I have been very happy over the years with their service.








						Search For...
					

The premier source of tooling, parts, and accessories for bench top machinists.




					littlemachineshop.com
				




Steve


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## Brian Rupnow (Sep 2, 2022)

I've spoken to Little Machine Shop. They do not carry this gear in metal.---Brian


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## terryd (Sep 3, 2022)

Jasonb said:


> Peter, look at the first page, first post of the thread and you will see the gear and the reason why it strips





jumps4 said:


> Hello Brian and others
> Little machine shop (littlemachineshop.com) carries metal replacement gears and parts for many of these import lathes and mills.
> It may be worth a look. You can call them by phone also.
> I have been very happy over the years with their service.
> ...


Hi jason,

Be careful what you wish for when replacing plastic gears with metal.  Plastic gears are often used to be sacrificial in the case of machine jamming to protect more expensive damage - rather like shear pins in shafts which are designed to fail before more serious damage is done to a device.  Most manual lathes have some kind of shear pin in the final drive to the leadscrew so that for example in the case of the saddle jamming against the headstock when in automatic drive the pin will shear otherwise serious damage to the clasp nuts or leadscrew can occur, so a 50p shear pin could save many £££s and time in repair costs.

When I was involved in designing drive systems to large machines, conveyor systems etc we would always include such a sacrificial device. just in case.  Just think, if that relatively inexpensive gear (which could easily be 3d printed at home) had not failed what other damage may have occured.  On our conveyor systems if a shear pin failed a production line would stop but it was a simple matter to locate the problem, fix it and then replace the shear pin so production would be down for a relatively short time compared with what would happen with major damage.

Terry


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## Bentwings (Sep 3, 2022)

Drawfiler said:


> . Is there enough rom to use a wider gear, like stacking two gears?
> These are made in plastic to deaden noise and vibration and work OK a until the day of the inevitable smash up when using a large cutter.
> I have made replacements in both metal and Acetal (Delrin) with good results so message me if I can help


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## kvom (Sep 4, 2022)

I suspect that the gear printed in Onyx fiber on my new Markforged printer would work well, as the material is about as strong as aluminum.


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## Jasonb (Sep 4, 2022)

Terry you are posting to the wrong person, I often post that if someone replaces a plastic gear with metal they may find that the next time they crash or overload the machine the board or motor will be what fails not the shiny new metal gear. I've certainly not suggested it or wished for it here.

Also if you read again the failure of Brian's was not due to it being a failsafe but an issue with the gear selector lever meaning it was not correctly meshed.

Plastic gears on some of teh imported tools are also specified on grounds of cost and noise reduction.


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## Bentwings (Sep 4, 2022)

kvom said:


> I suspect that the gear printed in Onyx fiber on my new Markforged printer would work well, as the material is about as strong as aluminum.


I looked up the onyx fiber spools snd material. It’s tough stuff if you can print it yourself it’s probably ok my as noted  fixing one weak linnoften leads to another  the motor and driver can be next and very difficult to replace the onyx is pretty good  but if you have to have it done outside check prices it may be better to just keep a couple spare gears on hand .


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## Toymaker (Sep 4, 2022)

Brian Rupnow said:


> I have a little story to tell. I have a CX601 milling machine from Busy Bee Tools and I love it. This milling machine does everything I want, except drill 1" holes in aluminum. I don't do that very often, but when I do, it's mostly ornamental holes thru flywheel webs. And this is the point where my mill lets me down. There is a nylon compound gear in the gear-head, and it lets you put the mill into the equivalent of "back-gear" on a lathe. About every two or three years, this compound nylon gear manages to strip all the teeth of one side. It costs around $70 for a new gear, and it's a royal pain to take the mill apart and replace the bad gear. It doesn't happen all at once. When it first decides to eat that gear, it jumps out of gear into neutral. If you can spare a hand to hold it in gear, it works just fine, but sometimes I run out of hands to do that. It doesn't take much force to hold it in gear, and I'm sure that if it was held firmly in gear so that it couldn't jump out, then it wouldn't wreck the gear. So, today I'm designing a third hand to hold the mill in "back gear" while I drill large holes. In the pictures, you will see a side view of my mill where the gear selector knob is, another picture that shows my "third hand" in position, and in the third picture you can see a bad nylon gear and it's replacement good nylon gear.



My "Mini Mill" uses similar plastic gears (below photo) and like your mill is also made in China.  I was able to purchase a replacement set of metal gears thru AliExpress for $30, and replacement plastic gears were even cheaper.

Hopefully you can find metal replacement gears on either AliExpress or eBay.


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## a41capt (Sep 6, 2022)

I 3d printed “emergency” gears in PETG and they’ve performed admirably.  Sure beats having your Mini Mill down awaiting replacements!

John W


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## Drawfiler (Sep 6, 2022)

if you are worried about metal gears being too strong to act as a safety device in case of a smash up, you could incorporate a small shear pin between the two gears, .062” dia would probably be big enough


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## Bentwings (Sep 7, 2022)

a41capt said:


> I just ran into a carbon fiber print material called onyx  it’s supposed t be stronger yet quiet running as a gear material .  Stronger but still be the saftey valve
> I 3d printed “emergency” gears in PETG and they’ve performed admirably.  Sure beats having your Mini Mill down awaiting replacements!
> 
> John W


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## a41capt (Sep 7, 2022)

I can’t quite get the nylon/carbon fiber material to run consistently.  I’ve even had trouble with ABS, but with PETG, while a bit more difficult than PLA, I can achieve acceptable results.  This is especially true when I don’t have large interior voids where stringing still becomes semi-problematic occasionally.  I just utilize a “brim”, set my perimeters to 4 or 6 and use a 50% to 70% infill.  As long as my fan speed is set relatively low, I can achieve some pretty awesome lateral strength.

Of course I still order the correct part, but my machine is only down 15 to 20 minutes while I change out the gear.  I’m still hoping to scrape together the cash to change over to a belt drive! 

John W


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## Bentwings (Sep 8, 2022)

a41capt said:


> I like the belt drive idea  maybe you could get fancy and make a step belt drive . You could machine your own pulleys if none are  conveniently  available .
> I can’t quite get the nylon/carbon fiber material to run consistently.  I’ve even had trouble with ABS, but with PETG, while a bit more difficult than PLA, I can achieve acceptable results.  This is especially true when I don’t have large interior voids where stringing still becomes semi-problematic occasionally.  I just utilize a “brim”, set my perimeters to 4 or 6 and use a 50% to 70% infill.  As long as my fan speed is set relatively low, I can achieve some pretty awesome lateral strength.
> 
> Of course I still order the correct part, but my machine is only down 15 to 20 minutes while I change out the gear.  I’m still hoping to scrape together the cash to change over to a belt drive!
> ...


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## kf2qd (Sep 9, 2022)

That is why many have rigged up a drive using a timing belt and sprocket. I never used high speed as it was always too fast for anything I have wanted to do. The sprocket gets mounted on the top of the spindle and the belt has lasted for years now.


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