# Tool Post Grinder



## Ghosty (Jan 23, 2018)

Hi All,
After looking around, I have started making my own grinder.
Power is a 500watt brushless motor, the shaft is a 20C ER20 150L collet shaft. Bearings 20mm x 32mm x 7mm, I used 4 to support the shaft, used a toothed belt with a 2-1 ratio. The brushes motor max speed is 12000rpm, so can get better grinding spindle speed control.
I have the basic setup done, with only some fine tuning to finish.
I still have the grinding wheel arbour to machine, will fit the ER20 collet shaft end.
The main body is machined out of a piece of 100mm x 100mm x 50mm alloy block, the motor mount spacer, is a piece of alloy 25mm x 40mm x 110mm, which is bolted to the main body, and then the motor mount is bolted to the spacer.
The alloy is what I had in the spares bin, the motor came from another project, and the belt and pulleys were extras from another project, bearings are used in a 1/5 Baja buggy that I run, only thing I ordered is the ER20 collet shaft. I also have a C12 ER11 150 collet shaft that can be set up to do internal grinding.
Will ad more as the project moves forward.

Cheers
Andrew


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## Herbiev (Jan 23, 2018)

Looking good so far. I'll be following along.


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## Brian Rupnow (Jan 23, 2018)

Nice work Ghosty. I have been trying to find a company that makes a toolpost mounted grinder like that one and had no luck. I would buy one if I could find a company that sold that style.---Brian


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## Ghosty (Jan 23, 2018)

Brian Rupnow said:


> Nice work Ghosty. I have been trying to find a company that makes a toolpost mounted grinder like that one and had no luck. I would buy one if I could find a company that sold that style.---Brian


 Brian,
I found this https://littlemachineshop.com/products/product_view.php?ProductID=2001&category=
Postage would kill me.

Cheers
Andrew


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## Ghosty (Jan 23, 2018)

Hi All,
Started on the arbour to hold the grinding wheel. Have to wait for the wheel to arrive, but will hope to finish the arbour today.

Cheers
Andrew


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## Brian Rupnow (Jan 23, 2018)

Ghosty--I've seen that as well, but in order to mount that on your lathe you have to remove the topslide. I would want one that actually mounts to the toolpost so it could have angular adjustment for grinding tapers.


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## Ghosty (Jan 23, 2018)

Hi All,
Grinding wheel arbour finished, can be removed from the ER20 collet chuck and a 12mm collet used with a C12 ER11 150L collet shaft and with the use of smaller grinding stones, it can be used to do internal grinding.
I still have the mounting hole to drill, stuffed up my back again, twisted the wrong way so will not be doing any more today.

Cheers
Andrew


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## goldstar31 (Jan 23, 2018)

Ghosty and Brian

I don't know whether the undermentioned. is pertinent but my tool post grinder  is a Bosch POF45 which I bought as a wood router some considerable number of years back. When I opened the box, the instruction were that it was actually a tool post grinder with a standard 43mm collar. Of course the collets  came with it for router cutters.

Cheaper still were the wood routers from sources like Aldi and Lidl.

Following a circuitous route( other peoples's), the wood router was /is the propulsion unit for the Brookes tool and cutter grinder which was described in Model Engineers Workshop 16 and 17 and mentioned in the excellent GadgetBuilder.com website.

I hope that this is interesting and 'constructive'


Norm


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## Ghosty (Jan 23, 2018)

Hi All,
Testing the drive and motor for the first time, forward and reverse.
[ame]https://www.youtube.com/watch?v=wqEgP0rsWfM&feature=youtu.be[/ame]

Cheers 
Andrew


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## Blogwitch (Jan 24, 2018)

Hi Andrew, just a comment about wheel speed.

I used to use my TG a lot, and looking at your setup, you will not be reaching the speeds required for grinding correctly, especially internal surfaces.

I have twin sheaves on mine, for internal and external, and both increase the speed from the motor (18K RPM ?) to the required speed for the stones. The belts used are flat plaited ones that when running on a convex pulley face allowing slippage if anything starts to get overwhelmed.

I am using a 2.5" stone for external and standard 1/8" shank mounted points for internal.

Maybe you should look at swapping your two pulleys over to get more speed from your TG.


John


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## Ghosty (Jan 24, 2018)

John,
I all ready have a internal grinder, made up to do one job, good for 30K rpm, bearings are not quite up to the job, will be rebuilding with larger bearings.
Blue sealed bearings are what I used, will be replacing with 6001's

Cheers
Andrew


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## Blogwitch (Jan 25, 2018)

They reckon angular contact bearings are the best ones to use and preload them. 
If you are going to use those bearings you have, then make a spacer tube the exact distance between the inside bearing surfaces, then you can slightly preload them so they don't move in and out as the bearings warm up.

My old TG doesn't have ballraces, but in fact are plain bronze with the internal of the spindle tube filled with oil. It has never leaked out at all. Supposedly plain bearings give a much better finish as they don't 'rumble', just like old plain bearing lathes.


John


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## goldstar31 (Jan 25, 2018)

In my reply to Jon( JC Steam), I suggested that a cheap commercially available  wood router could be suitable for similar loadings to those with the loads of routers. I can only surmise if firms like Aldi and Lidl who sell these things at knockdown prices  still guarantee them for THREE years in normal hobby use and without quibble.

Makes me think, if no one else.

N


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## DJP (Jan 27, 2018)

A wood router as a tool post grinder has already been logged in my project files when you first mentioned it. Thanks


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## Ghosty (Jan 28, 2018)

Hi All,
Belleville washers, and grinding wheel arrived, now to do the final clean-up and assembly of the grinder. It seams to work well, need to work out cutting speeds, the grinder was running at 4200rpm and the lathe running at 1000rpm.

Cheers
Andrew


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## Ghosty (Jan 29, 2018)

Hi All,
Got the grinder fully assembled, Now to set it up, dress the stone and test it out. It is a bit big for my current lathe, made it for a larger lathe(10" x 22"), my daughter found it for me, only problem it is 9 hours away(Coffs Harbour), will pick it up at the end of March, as I have to go to my daughters then for her wedding.

Cheers
Andrew


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## Ghosty (Jan 29, 2018)

Hi All,
After dressing the stone, I done a couple of passes on a hardened shaft. These are 1thou cuts.
[ame]https://www.youtube.com/watch?v=_5YWDZMRhlA[/ame]

Cheers
Andrew


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## Charles Lamont (Jan 29, 2018)

Andrew, the grinder is a nice job.

However, I hope you don't mind a few pointers: 

Old school books would insist you put loads of newspaper or something down to keep grinding wheel grit out of the slides.

They would also insist on card or blotting paper washers either side of the wheel.

You appear to have heavily 'glazed' the wheel with the first pass. I would suggest the cut was much too heavy for that wheel, especially without coolant.

I get the impression the wheel is too fine a grit for the job. 

Another suggestion, if the grinder is mounted on the topslide, is to set the topslide to, ideally, 5.7 degrees, then one division the topslide dial will give an infeed of  1/10 as much.


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## Blogwitch (Jan 29, 2018)

After watching and reading your previous post, I was going to suggest exactly the same as Charles, all his suggestions are spot on, plus, you should be working to tenths rather than thous, plus I see you have tried both directions of lathe rotation.

Here is a little diagram that describes the rotation thing.







John


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## goldstar31 (Jan 29, 2018)

Chaddock in his write up on his Quorn quotes a quarter thous as a whopping big cut.

I've already ticked my agreement with Charles' comments


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## Ghosty (Jan 29, 2018)

Hi All,
Thanks everyone for the advise, 
Charles, I used 0.4mm gasket paper between the holder and the wheel.
This was only a test as it is too large for this machine, the topslide is turned right around to get the clearance for the grinder.
I have started on a new one for the smaller machine.

Cheers
Andrew


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## Ghosty (Jan 30, 2018)

Hi All,
Got the new smaller grinder centered with the lathe. Had to machine close to 3mm of the bottom. 
I ordered a new motor for it as the old one run hot(designed to be water cooled in a boat), the new one has an internal cooling fan.

Cheers
Andrew


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## petertha (Jan 31, 2018)

I like the compactness of your design with ER collet shaft. Dumb question but the Bellville washers - are those to apply pre-load to what I understand to be regular bearings? I've never quite understood this in grinder spindles, is it to apply slight pressure to minimize initial play, or (acting as a spring) intending to allow thermal expansion growth at elevated running temperature? Whereas something like a fixed pre-load nut would be more solid so bearings would actually tighten up when running at temp.

How is that motor holding up temperature wise. Do you need to let it cool down after a certain amount of grinding?

How would your design look orientated on a part rotating between centers? ie does the tailstock interfere with the motor/spindle assembly?

Any chance you can sketch up the design? I'd really like to make something similar. I still lust for something compact but accurate like this.

http://www.homemodelenginemachinist.com/showthread.php?t=10618


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## Blogwitch (Jan 31, 2018)

Peter,

The picture shown is from the Bonelle tool and cutter grinder wheel spindle, and shows how it uses a spring effect to ensure that the preload is always present. There are lots of methods to do the same job, you need to find one that is easy for you to make. Some simple ones just use thin wavy spring washer to do the same job.
This is to allow the spindle to warm up and still have good contact with the bearings.

All machines, including lathe and mills, if they have taper bearings should always be run for a few minutes to allow spindles to reach their optimum lengths before use.

John


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## petertha (Jan 31, 2018)

That picture is helpful John. So if I understand
- the green tube is to keep the inner races as a set datum minimum distance, they are fixed?
- the grey spring fitting applies outward force to left outer race?
- does right (red) threaded fitting apply force to that outer race, or is more a cover?
- what kind of bearings does this design incorporate?

(I have a book on spindles but having trouble understanding what is intending to slide vs. locked down. It has several nice looking designs but nominal dimensions for the most part, little I can look at like +/- x.xxxx and conclude mild interference or close sliding etc.)


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## Ghosty (Feb 1, 2018)

petertha said:


> I like the compactness of your design with ER collet shaft. Dumb question but the Bellville washers - are those to apply pre-load to what I understand to be regular bearings? I've never quite understood this in grinder spindles, is it to apply slight pressure to minimize initial play, or (acting as a spring) intending to allow thermal expansion growth at elevated running temperature? Whereas something like a fixed pre-load nut would be more solid so bearings would actually tighten up when running at temp.
> 
> How is that motor holding up temperature wise. Do you need to let it cool down after a certain amount of grinding?
> 
> ...


Peter, 
The Belleville washer does both, apply a slight pressure and takes up any expansion due to heat. The bearings are deep groove bearings, and I use 4 bearings, 2 at each end.
The motor is rated at 100% duty cycle, it only gets warm.
The smaller one would fowl on the tail stock due to the size of the grinding stones

Cheers
Andrew


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## Blogwitch (Feb 1, 2018)

Peter,
The bearing are angular contact bearing. Like these

http://www.arceurotrade.co.uk/Catalogue/Bearings/Angular-Contact-Ball-Bearings

The red threaded things are just covers.

The other things you have correct , plus the end.nut on the sheave puts on the preload.

But as I have said before, this is a complicated one, a real easy one is as stated, the wavy spring loaded washer.

Go to your search engine and enter 'wave spring washers' then look at the images, it should show what I mean.

John


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## goldstar31 (Feb 1, 2018)

It's a big job to make one for a Quorn but Chaddock  gives a blow by blow set of instructions and the labyrinth is 'interesting' to say the least.

 I've also a simpler one on my Stent and another on my Kennet. The Quorn one is vastly better!

Probably the ready to use one from a Chinese router is not only cheaper but quite adequate  

Whatever turns you on- but the Quorn is a great teacher!!!!!!

N


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## DJP (Feb 4, 2018)

This is slightly off topic but related to grinding on a lathe. Do you wear a high quality mask when grinding with a tool post grinder? If the grinding dust can harm the ways I expect that it doesn't do much good for lungs.

Just curious as I have decided to wear a mask more often when there is fine particulate in the air.


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## Ghosty (Feb 6, 2018)

Hi All,
While waiting on parts for the small grinder, I made up a "safety shield" from a clear shield off a drilling machine.

Cheers
Andrew


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## Brian Rupnow (Feb 7, 2018)

Ghosty--I really like what you have done there. As near as I can determine, nobody in North America markets a toolpost mounted grinder like that.---Brian


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## petertha (Feb 7, 2018)

I haven't seen any 'marketed' either. There are a few other home shop builds +/- size & other features s below. But I really like the compactness of what Ghosty constructed. I hope you draw up some plans when its all done. Or several guys on the forum have the resources to help in that regard.

http://www.homemadetools.net/forum/tool-post-grinder-33437#post46937


http://www.homemadetools.net/site/search?q=tool+post+grinder&Search=


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## Ghosty (Feb 7, 2018)

Brian, petertha, Thank you, I will do a couple of drawings and post, It may take a week or so as I will have to look for the suppliers of the pullies, belt and motor as I bought them some time ago.
The smaller one I built was only for one job, under sized(20thou) bearing retainer rings(hardened) for axel bearings, It done the job but the small bearings started to fail at the end. I looked around for other grinder units and they were very over priced(over $2K) or the shipping would kill me. I don't know what some companies do for shipping but I went to order two small polly V belts from a US company, belts were only small, total cost of both belts were $4.40, $2.20 each, They wanted $119 postage.

Cheers
Andrew


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## Brian Rupnow (Feb 7, 2018)

Ghosty--It isn't just Australia. I live right next door to USA and most small items double in cost due to the difference in our dollars and the shipping. I try to always buy from Canadian suppliers. They buy from USA in batch lots and only pay one shipping fee on 500 items.---Brian


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## Ghosty (Feb 7, 2018)

Hi All,
Here is the main body, I used a C20 ER20A 150L shaft, Bearings are 6804RS 32x20x7 used 4, All can be sourced through e-bay 30 tooth pulley has 20mm hole, 15 tooth pulley has 8mm hole, belt is 15mm wide  check when ordering

30 tooth pulley, 
https://www.ebay.com.au/itm/HTD-5M-...hash=item3d26198fdb:m:m0oBR1ZasZ3_f6HbwZVnIsw

15 tooth pulley, 
https://www.ebay.com.au/itm/XL-Type...144308&hash=item3f3bded036:g:j80AAOSwHAdZt89G

350mm Belt, 
https://www.ebay.com.au/itm/Synchro...hash=item3f8ee90858:m:mUWWBxowG5iNkCelNP6caUw

Brushless Motor, 
https://www.ebay.com.au/itm/48V-CNC...490857?hash=item46729b4be9:g:rKwAAOSwvTpaOMyq
Hope this helps, will try to get more done later. 

View attachment Grinder.pdf


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## Ghosty (Feb 7, 2018)

Hi All,
Adaptor plate

Cheers
Andrew 

View attachment Grinder 2.pdf


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## Ghosty (Feb 8, 2018)

Hi All,
Grinding wheel holder, this has been machined to take these wheels, https://littlemachineshop.com/products/product_view.php?ProductID=2585&category=
Some dia may have to be changed to suite the wheel that you use.

Cheers
Andrew 

View attachment Grinder 3.pdf


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## Ghosty (Feb 13, 2018)

Hi All,
Motor arrived for the small grinder today, It is going to be a hot one today, mid to high 30's C (around 95-100F), need to make up another motor pulley and machine engine mount plate to take the motor, don't know how much will get done.

Cheers
Andrew


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## Ghosty (Feb 14, 2018)

Hi All,
Ended up getting too hot for me today, only got the motor mounted. Will see what tomorrow brings, still 37degsC here now

Cheers
Andrew


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## Ghosty (Aug 7, 2018)

Hi All,
I now have my new lathe set up, custom fitted the grinder to the lathe, centre height required a 4mm spacer to rise the grinder centre line to the lathes, also required a 20mm spacer for the hole down bolt, still waiting for the live centre for the tailstock to arrive, old lathe was a MT2, new one is a MT3, before I can re test the grinder function. Also shown are two grinding wheels that I have at the moment. Will have to look at the guard to fit the larger wheel.

Cheers
Andrew


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## Ghosty (Aug 11, 2018)

Hi All,
Set up the power supply for the grinder and done a test grind on some bright steel rod, worked out well.

Cheers
Andrew


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## dkwflight (Aug 11, 2018)

My two Version' Mounts on my QCTP
I have a viberation at the chuck


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