Tool post grinder

[Silverbullet]

If you need one you own it . That grinder is well made so use it , get a smaller wheel mount it and dress it on the lathe mounted . Cover your ways and machine surfaces with drop cloths or towels if old give a spray of light oil or wd40 it'll help the grindings stick to them and not the machine. And if you don't like the grinder put my name in the hat too. With the machine you have another spindle with collets can be built easily . Er 11 collet chuck with straight shaft will be the spindle it's easy .

 

[Clock work]

I decided to move forward on the home-made (with an axe? TPG instead of buying new given the encouragement here (thank you again). I took the old motor apart and it was junk... loose.. sloppy... wouldn't put it in a desk fan. That homemade spindle though feels pretty tight so moving forward. Found me a nice sealed Dayton 1/2hp 3450 rpm grinder motor on eBay at a killer price ($40 new). Again... fully disclosing my daunting lack of experience on these particular matters, it just feels too heavy to subject my 10K's cross slide t-slot to and the resulting torques. I'm curious if the more knowledgeable here agree or disagree? I'm guessing there might be a smaller motor on eBay if I go look again and I can always put this on something else... I don't seem to be running low on projects.

CW

 

[Bob Korves]

I decided to move forward on the home-made (with an axe? TPG instead of buying new given the encouragement here (thank you again). I took the old motor apart and it was junk... loose.. sloppy... wouldn't put it in a desk fan. That homemade spindle though feels pretty tight so moving forward. Found me a nice sealed Dayton 1/2hp 3450 rpm grinder motor on eBay at a killer price ($40 new). Again... fully disclosing my daunting lack of experience on these particular matters, it just feels too heavy to subject my 10K's cross slide t-slot to and the resulting torques. I'm curious if the more knowledgeable here agree or disagree? I'm guessing there might be a smaller motor on eBay if I go look again and I can always put this on something else... I don't seem to be running low on projects.

CW

Take a look at the Dumore site and see what they are using on their tool post grinders. I have a 44-011 Dumore, their second largest one, recommended for lathes with 8-14" swings, and it has a 1/4 HP motor that is quite small and light, though high speed. It works fine for the light jobs I use it on. Pay attention to motor RPM and pulley and wheel sizes, for both internal and external work. Grinding typically works best at around 5,000 SFPM. Do the math for the wheel sizes, motor speeds, and pulley combinations you might expect to use on the grinder.
https://www.dumoretools.com/tool-post-grinders

 

[Bob Korves]

You might also want to look at a manual as well to learn a bit more before getting started on it:
https://www.dumoretools.com/documents/Tool-Post-Grinders-Dumore-Series-44-Operating-Instructions.pdf

 

[f350ca]

I wouldn't be concerned about the weight, think about the forces the cross slide sees when machining. But that motor probably won't be fast enough. As Bob pointed out you need to get the grinding wheels and points spinning at their recommended speeds. To get a mounted wheel running 20,000 + rpm you'd need a pretty big drive pulley. The motor on my Dunmore, (forget the model) is a universal type motor, guessing in the 10-20,000 rpm range. Maybe a small wood router would be a good donour.

Greg

 

[bill70j]

Maybe a small wood router would be a good donour.

Agree on the router motor. Either a trim router or a full-sized router motor will work. I have both. They can get you 24K RPM for internal grinding, and with a potentiometer and pulley change, you can get down to 5K RPM for external grinding with a 3" wheel.

The cheap HFT routers both have good donor motors.

 

[Clock work]

Guys... thanks. I wasn't paying close enough attention to the mission. I do love the suggestion of HF as an organ donor as I have several I don't ever seem to even touch anymore... probably the trim router sitting under a quarter inch of dust, as Bill suggested. After I fix the chuck, I don't see me using it again and hope to move to a surface grinder asap for all other grinding...

Appreciated!

CW

 

[bill70j]

CW:

If you're going to build your own TPG, and haven't built a spindle before, there is a book that has some very good information on building your own spindle - including drawings in metric and imperial. It is a trifle difficult to follow the author's writing, but all the info is there. You can pick up a used copy for less than $10 off Amazon.

Bill

 

[Clock work]

CW:

If you're going to build your own TPG, and haven't built a spindle before, there is a book that has some very good information on building your own spindle - including drawings in metric and imperial. It is a trifle difficult to follow the author's writing, but all the info is there. You can pick up a used copy for less than $10 off Amazon.

Bill

Bill... thank you for taking the time. It's already in my cart. I enjoy several other books from that series. I think for my one-off need, I think I can make the one on the original TPG that started this work but it'll be modular.. I can swing another in if I need to, but the original spindle feels like the only rock-solid part of it. Still going to enjoy the book (when I finish reading the heat treat book from that series actually)... I'm amazed at the extraordinary precision our species has built up.

CW

 

[pontiac428]

CW:

If you're going to build your own TPG, and haven't built a spindle before, there is a book that has some very good information on building your own spindle - including drawings in metric and imperial. It is a trifle difficult to follow the author's writing, but all the info is there. You can pick up a used copy for less than $10 off Amazon.

Bill

Or you can download that book (and most of the series) in the downloads section of this site...