# Dumore Tool Post grinder



## tmenyc (Nov 17, 2018)

With the purchase of my Logan 820 I received a ton of stuff, including a Dumore 44 tool grinder mounted to the compound.  I want to bring that back to life for tool sharpening, and am shopping for silicon carbide cutting wheels. I'm guessing the Dumore was purchased contemporaneously with the 820, new in 1943.  
However, the Dumore needs, at a minimum, a new belt.  I've written to Dumore for a parts diagram and operating instructions, but also want to see if anyone here has these and tips, warnings, or suggestions for me.  It's a great piece, I would never have bought it on its own, but I'm thrilled to have it and want to use it. 

TIA, I love this board!  

Tim


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## Ulma Doctor (Nov 17, 2018)

congrats on the new to you Dumore! 
Ebay has tons of grinding wheels for you.

one tip off the top of my head...
light cuts (.0005"per side) and slow carriage advance will produce better finishes than heavy grinding and fast carriage speed
always wear eye protection

an assortment of different wheels will increase the capability of what you wish to use the grinder for.

the grinder is capable of doing both inside and outside grinding work.

you'll use relatively small high speed wheels for ID grinding and relatively larger wheels for OD grinding

use spindle oil to lubricate the spindle

Have lots a fun learning!!!


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## Bob Korves (Nov 17, 2018)

I also have a Dumore 44 TP grinder.  I made a sleeve that goes over the mounting post that brings the grinder accurately to lathe center line height just by installing it under the motor/spindle assembly.  Saves lots of setup time.  The grinder works well, but they are not very rigid, so Ulma Doctor's advice for taking a light infeed is a very good idea if you want nice results.  It does take some time.  The work I have done with small internal wheels has been very slow due to flexible wheel shanks.  O.D. grinding is a lot more rigid.  Larger diameter internal grinding with more rigid setups would also probably work well.  Very light spindle oil is correct for the spindle, due to the high RPM's.  Just a few drops, don't fill it!

The manual for the grinder is downloadable free online from Dumore:
https://www.dumoretools.com/tool-post-grinders/series-44
https://www.dumoretools.com/documents/Tool-Post-Grinders-Dumore-Series-44-Operating-Instructions.pdf

The parts list is included with the operating instructions.  Note the current price for one, $1,942.00 !!!  Factory parts are probably equally pricey.


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## 4ssss (Nov 17, 2018)

Good luck getting anything from Dumore. IMO they are the worst when it comes to customer service.


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## tmenyc (Nov 17, 2018)

thanks all -- much appreciated.  Getting the Dumore working is not near the top of my priority list right now...have too much core stuff to learn first! This is good though.  I'll get the downloads and hang on to them.  

Tim


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## bill70j (Nov 17, 2018)

4ssss said:


> Good luck getting anything from Dumore. IMO they are the worst when it comes to customer service.


Your service rep must have been in a bad mood - or mine was in a good mood.  I ordered two wheels and a mounted point from them and got a note two days later that the package had shipped, along with the UPS tracking number.


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## chips&more (Nov 17, 2018)

A tool post grinder can be handy. BUT, it can also be a death call to the lathe it’s used on. The grinding swarf that it makes can destroy precision mating surfaces. When using, cover everything well! And I would get some white, pink and diamond wheels for it. Generic belts are easy to find. Good Luck…Dave


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## lordbeezer (Nov 17, 2018)

Vacumn cleaner belts will work.right size of course


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## bill70j (Nov 17, 2018)

lordbeezer said:


> Vacumn cleaner belts will work.right size of course


Agree.   Also, this grinder/spindle/wheel company knows the business and will get you the right flat belt specifically for your TPG at a very reasonable cost, including one for your Dumore.  They have great customer service.


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## benmychree (Nov 17, 2018)

Belts from William Sopko company. Silicon carbide wheels are not for steel, get aluminum oxide.


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## tmenyc (Nov 17, 2018)

Thanks, all. Very helpful.
Tim


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## mmcmdl (Nov 17, 2018)

A bit of safety advise ........don't stand or sit in front of the quill when running . I've had wheels disintegrate in the past on internal grinders . They go along was FAST ! Also , keep that smaller wheel dressed .


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## ddickey (Nov 18, 2018)

I thought I heard once that you do not dress internal wheels, did I hear correctly?
Doesn't make sense but....


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## Bob Korves (Nov 18, 2018)

ddickey said:


> I thought I heard once that you do not dress internal wheels, did I hear correctly?
> Doesn't make sense but....


Not correct, Duane.  Grinding wheel grit grains get dull, they wear down, and the spaces between them get full of swarf.  The wheels must be dressed to keep them cutting properly, and to keep the desired shape on the wheel face.


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## ddickey (Nov 18, 2018)

Thanks for the clarification Bob.


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## bill70j (Nov 18, 2018)

Bob Korves said:


> Not correct, Duane.  Grinding wheel grit grains get dull, they wear down, and the spaces between them get full of swarf.  The wheels must be dressed to keep them cutting properly, and to keep the desired shape on the wheel face.


Agree, and in some circumstances it makes sense to grind a relief behind a mounted point's leading edge, for example when grinding chuck jaws.


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## ddickey (Nov 18, 2018)

Behind but on the same plane, so less contact?


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## bill70j (Nov 18, 2018)

ddickey said:


> Behind but on the same plane, so less contact?


Yes.  When I ground my chuck jaws I started with a W cylindrical shape and found the results were more controllable with less contact and very small 0.0005" depth per pass.  The conical shape I ended up with worked the best.


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## mmcmdl (Nov 19, 2018)

All above are true . Your internal wheels load up just like your external wheels . ( especially if they are not relieved on the back side ) They will build up pressure while grinding and break down on you when you least want it to ! All of our grinders had flood coolant and this still occurred . Heat is your worst enemy in the grinding process . That wheel wants to bite into your part . Keep your wheels dressed and undercut the rear for best results . Diamond and Borazon wheels don't need dressing , they are used for specialty jobs such as chrome .

I have a little Precise grinder and a smaller Dotco that wind out at 80,000 rpm . It's interesting when the wheels break down ! 

I prefer to use Norbide sticks for dressing over mounted diamonds also . Those smaller wheels sometimes grab the diamond and that's where the fun really begins !


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