Tool Post Grinder

[Ghosty]

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

 

[Ghosty]

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

 

[petertha]

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

 

[Blogwitch]

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

 

[petertha]

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.)

 

[Ghosty]

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://

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

 

[Blogwitch]

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

 

[goldstar31]

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

 

[DJP]

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.

 

[Ghosty]

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

 

[Brian Rupnow]

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

 

[petertha]

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=

 

[Ghosty]

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

 

[Brian Rupnow]

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

 

[Ghosty]

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

 

[Ghosty]

Hi All,
Adaptor plate

Cheers
Andrew

View attachment Grinder 2.pdf

 

[Ghosty]

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

 

[Ghosty]

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

 

[Ghosty]

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

 

[Ghosty]

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