Tool Post Grinder

I built this little grinder mainly for truing the jaws on my lathe and lathe centers, Maybe some light O.D. & I.D. grinding too.

The grinder has two interchangeable spindles, One for I.D. work which holds mounted stones with 1/4" shanks, The O.D. spindle supports up to a 4" O.D. tool post grinding wheel up to 1/2" wide.
The spindle is supported by two 5202 Double row shielded angular contact bearings rated at 10,000 RPM's. I machined 4 aluminum pulleys to accommodate the proper rpm's for I.D. & O.D. grinding. The I.D. spindle runs at 10,000 rpm while the O.D. spindle runs at 6,000. Changing spindles takes about 3 minutes.

The motor is a Dayton 1/2 HP 10,000 rpm, That I got off e-bay, The bearings were ordered from Mc Master-Carr, The flat belt came from vbeltsupply.com, The hardware came from local suppliers.

The grinder runs very smooth and relatively quiet, It did an excellent job on my lathe jaws, After they were ground I had a .0007" run out, Not to bad for a 3 jaw chuck.

This grinder will fit lathes with a 10" swing and up with the correct spacer

Below are some photos and a couple links to you tube showing the grinder in use.

As always thanks for looking and happy machining

Doug

Click this link to purchase a set of these plans http://www.homemadetools.net/forum/t...er-plans-46306

Attachment 7363

All the parts ready for assembly

Attachment 7364

External spindle installed

Attachment 7365

Internal spindle installed

https://youtu.be/b5hKySgDVFA

Internal Grinding

https://youtu.be/iXb-niXkiKg

External Grinding

Click this link to purchase a set of these plans http://www.homemadetools.net/forum/t...er-plans-46306

Excellent work, and outstanding post!

Thanks rossbotics! We've added your Tool Post Grinder to our Grinding category, as well as to your builder page: rossbotics' Homemade Tools. Your receipt:

<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="http://www.homemadetools.net/tool-post-grinder-16"><img src="http://www.homemadetools.net/uploads/139267/tool-post-grinder-16.jpeg" /></a></div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="http://www.homemadetools.net/tool-post-grinder-16">Tool Post Grinder</a> <span> by <a href="/builder/rossbotics">rossbotics</a></span> </div> <div class="tags">tags: <a href="http://www.homemadetools.net/tag/grinder">grinder</a>, <a href="http://www.homemadetools.net/tag/pulley">pulley</a>, <a href="http://www.homemadetools.net/tag/tool-post">tool post</a></div> </div> </div> </div>

Doug,

Excellent design and work as usual that shows in all your homemade tools. Thank you for references to the shielded angular contact bearings.

I am curious about your chuck jaw grinding. What method did you use for pre-loading the chuck jaws during your grinding process? I have seen some toolmakers hold a thin washer set into a recess way in the back of the jaws, some have a special clamp that fits over the angular edges of the jaws to hold them taut while others just rely on high speed centrifugal force to hold the jaws under tension. Just curious about your technique.

Thanks for the posting, Paul

Super nice, and quiet too. I'm with Paul about the pre-loading? Looked like some kind of 60º wedge braces in the first vid?? Seven tenths really Rocks! Not Bad...LOL! Really terrific docs/write up, with your usual Thoroughness!! The internal spindle washer is a beautiful design. How did you do the .625 radius to match the bore of the spindle? Also curious about the 10k motor and rough price for it...never saw one with that frame style, but looks real handy for mounting. Thanks very much for sharing another of your great build!! ~PJ

Thanks PJ's for your compliments
I preloaded the jaws with 3 pieces of 1/2" plywood, I cut them about a 10° angle on each side and placed them against the chuck face, I then just screwed the jaws down until they tightened themselves against the wood pretty snug and ground away, I fed the grinder in and out until there were no sparks ( by power feed of course ).

The .625 Radius was cut with a boring head. I took a scrap piece of aluminum plate and bored a 1.750" hole, There is your radius, I then put the base in the mill vise on it's edge and moved in about .050" at the time and machined it like you were boring a hole. You can figure the rest I'm sure.
The motor is a Dayton, Model # 2M145, I got it new off e- bay I paid $145.00 for it.

Thanks Again Guy

Doug

Thanks Paul for your compliments
I preloaded the jaws with 3 pieces of 1/2" plywood, I cut them about a 10° angle on each side and placed them against the chuck face, I then just screwed the jaws down until they tightened themselves against the wood pretty snug and ground away, I fed the grinder in and out until there were no sparks ( by power feed of course ).

Thanks Again

Doug

Great work.
However, can you explain how a grinder would be more accurate than a cutter? Won't the grinding wheel wear down changing it accuracy?
Noo-bee machinist, Brian

Truly My Pleasure, Doug. I learn a lot from your designs and ways to do things...and sure a lot of others do to. Good idea about the ply will give it a try...not sure I can reach 7 tenths though! :lol:

Still a bit confused about the "Spindle Housing Retaining Washer" and may have been a bit unclear above. I thought about it and thought a simple way would be to take a piece of 1.25 RB or larger, turn to size and then mill the flat and drill the holes and CS's??

Nice deal on the Motor!

Thanks for taking the time! ~PJ

Oh PJ"s LOL
I was wondering when someone would ask about how I attached the spindle housing to the base, I left that undocumented just to see if anyone even noticed how that was done, congratulations to you sir.

If you look at these 3 drawings, the base, spindle housing , retaining washer, If you notice the radius on the retaining washer is the same radius as the bore on the spindle housing itself, In other words the washer goes inside the spindle housing, look at the drilled hole layout on the spindle housing, it's the same as the washer, now look at the base drawing where the radius is machined, there are two 1/4 tapped holes in the end of the base, the spindle housing has 2 sets of holes, the smaller set is for attaching the spindle housing to the tube by means of the retaining washer and the larger is for inserting the 2 flat head screws and a hex wrench from the other side.
Bet you can figure it out now

Thanks Buddy
Doug

A good work, based on the idea used on Schaublin and others small lathes makers, but a lot less expensive.:thumbsup:

I have exactly the same construction for a Schaublin 70 with the improvement of the independent motor you've made.

One is glad to be of service, Doug. What I was initially impressed with was the 17.5 thou of radial clearance between the shaft and retaining washer to allow the shafts to be "carefully" installed in the housing/bearings and cleverly using a 9/16 UNF for the retainer on the pulley end. Again, Excellent design, IMHO. The design reminded me of T-nuts for 80/20 or Bosch extrusions. I assume I'm right about using Round Bar to start with. Thanks again for sharing all this! ~PJ

Doug,
Thank you for your explanation for how you attached the spindle housing and still have the thickness of the retaining washer clear the spindle when the spindle is inserted.
Paul

Hi Doug,

Thanks for another great contribution! Your Tool Post Grinder is the 'Tool of the Week'!

As you've already received one of our official HomemadeTools.net T-shirts, we'd be glad to award you a $25 online gift card.

Just send me your email address via PM and we'll get things processed directly.

Congrats!

Ken

Congrats Doug! Well deserved! ~PJ

That makes 9 Tool of the Week wins for rossbotics. One more and we have our first 10-Time Tool of the Week award winner.


Here are all of rossbotics's 9 Tool of the Week wins:

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</div> </div> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="https://www.homemadetools.net/forum/tool-makers-vise-18400#post25623"><img src="https://www.homemadetools.net/uploads/118802/toolmaker-s-vise-2.jpeg" /></a></div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="https://www.homemadetools.net/forum/tool-makers-vise-18400#post25623">Toolmaker's Vise</a> <span> by <a href="/builder/rossbotics">rossbotics</a></span> </div> <div class="tags">tags: <a href="https://www.homemadetools.net/tag/vise">vise</a>, <a href="https://www.homemadetools.net/tag/machining">machining</a></div> </div> </div> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="https://www.homemadetools.net/forum/indexing-fixture-27750#post37609"><img src="https://www.homemadetools.net/uploads/129644/indexing-fixture-2.jpeg" /></a></div> </div> <div class="head 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From Canada

Nicely done and documented. I am always looking for ways :-) and means.

Bob

Now I know what my next project will be. Really nice work and thanks for posting!

Very nice design, I've been thinking about building one for some time now. So I've been studying the drawings, and am a little confused about a couple of things. In looking at the Grinder Base drawing, I see the dimension between the two holes that attach the Base to the Spindle Housing to be 1.250", but the Spindle Housing drawing shows the dimension to be .750 inches. The second thing confusing me is the Spindle Housing drawing shows the Base attaching close to one end of the housing, yet the pictures appear to show the base attached to the middle of the housing. Since the motor specs show the motor to be about 6" long, I could see the motor having to be attached toward the front end in order for the pulleys to line up at the back end.
Could there have been a design change between the drawings and the actual finished grinder? Is the spindle housing longer than 6 inches?
I only bring this up in case someone builds this from the plans and things don't line up right.

Thanks a lot for the design, it helps a lot in my thinking process, Steve

Very nice design. What I'm most interested in however is a source of high speed flat belts. I went to the source you quoted for the flat belt, but only found variations of v belts. I have used poly belts, but they are too flexible for higher speeds. Could you give us a bit more information on the belt you used?

Thanks, Steve

Thanks Steve
The belt I used was a jason flat belt 25.5", can be found at the link below, if the link doesn't work then just type in the search FLAT BELT it will take you the flat belt page there you will find the jason 25.5 belt
Jason 25.5M075 Flat Belt

Thanks
Doug

Great job! I have been thinking about a tool post grinder for my Myford lathe, and a design such as this is perfect. Nice Clausing lathe as well.

Quote:

---

Originally Posted by rossbotics

I built this little grinder mainly for truing the jaws on my lathe and lathe centers, Maybe some light O.D. & I.D. grinding too.

The grinder has two interchangeable spindles, One for I.D. work which holds mounted stones with 1/4" shanks, The O.D. spindle supports up to a 4" O.D. tool post grinding wheel up to 1/2" wide.
The spindle is supported by two 5202 Double row shielded angular contact bearings rated at 10,000 RPM's. I machined 4 aluminum pulleys to accommodate the proper rpm's for I.D. & O.D. grinding. The I.D. spindle runs at 10,000 rpm while the O.D. spindle runs at 6,000. Changing spindles takes about 3 minutes.

The motor is a Dayton 1/2 HP 10,000 rpm, That I got off e-bay, The bearings were ordered from Mc Master-Carr, The flat belt came from vbeltsupply.com, The hardware came from local suppliers.

The grinder runs very smooth and relatively quiet, It did an excellent job on my lathe jaws, After they were ground I had a .0007" run out, Not to bad for a 3 jaw chuck.

Below are some photos and a couple links to you tube showing the grinder in use.

As always thanks for looking and happy machining

Doug

Attachment 7363

All the parts ready for assembly

Attachment 7364

External spindle installed

Attachment 7365

Internal spindle installed


External Grinding

---

Drawings would be nice to show how spindle is attached to the base and how the bearings are arranged. Internet Explorer will not show the embedded videos when I look at the thread, just a large blank area.

That is a very nice and useful tool. If you fellows can't find that motor on Ebay, it can be had from W.W. Grainger Inc. I believe they also have a speed control for it if you want to spend the extra money. That motor is the perfect choice for that project. I have been thinking of putting one my old Dumore tool post grinder that needs to be rebuilt.

Very nice tool post grinder Rossbotics. I'm new to the forum but will grab a set of your plans. I really want to make a 'mini' version something along the lines of link for smaller, more finicky, sometimes angular work, but mounted on my 14x40 lathe. I bought a book on making spindles. I think I can make the various designs, but I still don't have a firm grasp of underlying principles of bearings selection. Some are plain & use anti-backlash adjusters, others use a spring, some call for angular contact bearings... It doesn't really elaborate on 'how much accuracy' or 'how long before heat issues' etc.

Can you describe the logic of what you chose & why. I cant quite tell by pics but do you have axial adjustment or compensation specific to the bearings?

two small grinding and milling spindels - Home Model Engine Machinist

https://www.amazon.ca/Spindles-Harpr...pindles+sandhu

Hi Petertha
Thanks for your comments, there are spindles you can buy, spindles normally have class 7 bearings and are called spindle bearings, and sold in matched pairs, those are quiet expensive, for no more grinding than I do the angular contact bearing in each end of the spindle works just fine, and yes it does have an adjusting nut to take out any end play, the angular contact bearing will take radial and axial loads, this is why I chose that particular bearing, If I were to be grinding on a daily basis say 6 hours a day then I would have went to the class 7 spindle bearings or better yet just purchased a spindle
According to the specs on the bearings I chose they are good for 10,000 RPM's, If you are going to be doing production work then I highly suggest you purchase a manufactured spindle.

Thank You For Your Inquiry

I bought your plans so will look them over closely. I got hold of a Themac last year & used it a bit (ID grinding cylinder liners for this 1/4sc model radial engine I'm building). Its a bit intimidating to me but doing the job. But for smaller things I was contemplating like valve shafts & seats or similar things at off angles, I'm finding the Themac a bit clunky to orientate, hence wondering out loud about constructing a homebrew 'mini' version.

Can you provide me guidance on the flat belt selection? Is that mostly a tangential speed thing, power related or certain length that this becomes critical? My Themac has very similar belt you are prescribing.

Also, would you consider it dangerous to orient the spindle at some angle, say 30-deg to lathe axis, but traversing in the same direction as bed with chamfered wheel? This mode would buy me some room around tailstock but now wheel is seeing some component of side load. I would envision max 1.5" dia wheel if that's helpful.

thanks again!

First off Thank You for purchasing my plans.

I purchased my belts from this company http://vbeltsupply.com I had a very hard time finding flat belts, you might say I built the grinder to match the belt instead of the other way around, my rule of thumb is to keep flat belts thin, narrow and short as possible due to vibration, also these braded belts are very strong, your not going to destroy them with fractional horsepower.

I have many times oriented my spindle at different angles to provide clearance, I don't think I would go over 30° though, it's possible you might create to much side pressure on the wheel and have a catastrophe like you say, and keep the wheel diameter small, say 2".

Just remember to keep the RPM's of the wheel to the manufacturers suggested speed.

Thank You
Doug

Hi All,
I just finished the tool post grinder. I had a few challenges but got it finished, almost. I need to get the spacer block turned down some. Runs great. I hope to try it out in the next few weeks.
Attachment 22140
Attachment 22141

Looks Great
Did a nice job attaching to your slide

Doug

Nice work ddickey! Would you like a free set of any of rossbotics's other plans? HomemadeTools.net will purchase them from rossbotics and send them to you for free, for posting your build.

Here are all of the plans: https://www.homemadetools.net/forum/...082?#post65890

Let me know which plans you'd like and I'll send them out to you.

ddickey - we just launched rossbotics's new Tailstock Taper Turning Attachment plans, and I've sent them to you for free per your request. Thanks again for posting your build!

Thanks much!

Hi rossbotics,
Nice work as I said in 2016, this system is just perfect on all points.

Just out of subject but it's memory, they were many little small firms around the threee swiss lakes region which made exactly the same principles of form and construction about 40-50 years ago when I was an apprentice especially for the Schaublin 70 and 102 or Simonet and other clones, and I never understood why this idea was abandonned since about 20 years( the CNC kills it in my opinion), it is a economical in material solution and not expensive to construct for all single or small serie production.
If you want a clean surface to mount a ball bearing for example, it makes the job in 5 minutes.
The standard grinding wheels were 50X10mm and in this size you can found about everything in grain or width in the past, now it's on the second hand market, and it was propelled with a round belt, the actual endless flat belt was not invented, the most expensive version was made with a B8 chuck.
I've found the original Schaublin illustration from 1950 catalog which was not so good as the clones, the n°445 on the illustration, it's too short, yours is better for this reason especially for inner grinding.
Attachment 24639

Hi Doug, thought you would like to see my version of your excellent tool post grinder.
I had to down size it a bit for my little lathe.

Cheers, JR

<!-- BEGIN /var/www/html/homemadetools/protected/modules/zeus/views/tool/postUpdate.php -->
Thanks jjr2001! We've added your Tool Post Grinder to our Machining category,
as well as to your builder page: jjr2001's Homemade Tools. Your receipt:

<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="http://www.homemadetools.net/homemade-tool-post-grinder-32"> <img src="/uploads/220424/homemade-tool-post-grinder-32.jpeg"/> </a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="http://www.homemadetools.net/homemade-tool-post-grinder-32">Tool Post Grinder</a> <span> by <a href="http://www.homemadetools.net/builder/jjr2001">jjr2001</a></span> </div> <div class="tags">tags: <a href='http://www.homemadetools.net/tag/grinder'>grinder</a>, <a href='http://www.homemadetools.net/tag/tool-post'>tool post</a> </div> </div> </div> </div>
<!-- END /var/www/html/homemadetools/protected/modules/zeus/views/tool/postUpdate.php -->

jjr2001 - nice work. Since you posted a tool you built from plans, we'll buy you another set of plans of your choice for free. Let me know which ones you want and I'll send them over to you.

Thanks for all this information about those important tool, what do you think from the difference of prices/quality between the stores with the bearings, have you tested why this is so important, personally I'm using those in the middle range but do the cheaper function in your opinion?
Attachment 28920Attachment 28921Attachment 28922

Very nice construction and write-up. Well laid out as always in your posts.
Unfortunately I was unable to view the video footage - "this video unavailable".

Kind regards, Tony.