# My Lil Dumore Tool Post Grinder



## darkzero (Sep 5, 2014)

I have a couple of 2.5" micro chucks that I wanted to grind the jaws on,  also wanted to make some centers. So I tried some tests (OD grinding)  with a Dremel mounted on the tool post. Didn't like the results at all,  no surprise there. I guess I could have mounted it more securely but  didn't bother trying any further. Seems like other people do have luck  with Dremels on small lathes.



(Not actually grinding here, took this pic when I first got the lathe test fitting my Dremel holder from my 8x14)






Then I bought one of these cheap pencil die grinders. Planned on making a  boring bar style tool holder to mount it. Figured it would be less flex  than a plastic Dremel body & would do what I needed.






Luckily I never got around to it. I found a baby Dumore locally for  pretty cheap. It's their smallest model, 1/14 HP! Haha. Should be ok for  what I need though hopefully.






But it needed a little care. Not sure why but someone spliced into the  power cord & added a second switch. Both switches are functional,  need to turn on one to activate the other, perhaps a safety they had in  mind? The cord had seen it's days too, dry rotted & ground pin  broken off.






Disassembled it and found that the original switch had a hole in it.  Thought maybe that was the reason for the second switch but the original  needed to be flipped to power it up. I tested it numerous times &  it works fine but I decided to replace it anyway while I have it open.  Also got a new grommet for the new power cord.











But before putting it back together. Someone had ground down one of the  alignment pins. I pressed the pins out, cleaned them up on the lathe,  & was able to reuse them. Also slightly lapped the spindle assy's  mating surface to remove any high spots just in case.











Pressed the pins back in with my 3 ton arbor press that I got recently.  J/K of course, I no longer have the small one but the pins only required  light taps with a hammer anyway.








Now it's ready to go back together. Got rid of the butt connectors &  soldered the connections. Also added a rubber toggle switch boot for  the heck of it.





Machined a new T-nut for it. (Reminds me of when Barry first did my Dorian one)






It came with 2 belts, extra arbors, extra crowned pulleys & some  wheels. It can do ID & OD. I'll probably end up buying new stones  later anyway. I ordered a couple of new belts from Sopko but haven't  tried them yet, the old belts seem to be ok still. I still need to make a  simple holder for the diamond dresser I picked up. Can't wait to do  some testing with it.


----------



## chips&more (Sep 5, 2014)

Lookin good! Didn’t read or see anything about yah poking around at the bearings at the business end. I would highly recommend the bearings be looked at. That power cord is a sign of its age and grease dries up with age as well. Especially the grease that was made before synthetics showed up. A little cleaning and fresh grease can be a good thing/insurance. And if there is anything left of my memory???? I seem to recall that the motor bearings are hard finding or not available anymore? Hope the bearings in your motor are OK. Again, recalling on my memory??? If you need motor bearings I think you will be finding a smaller bearing and making a bushing?


----------



## darkzero (Sep 5, 2014)

Thanks for the recommendation. I did think about the bearings as I hear that's a common problem on these old grinders. I only took a picture of the real motor bearing since Iit was exposed. It didn't feel gritty nor did the others. I would like to replace them though for good measure. That rear bearing was a ND 77037 (off the top of my head) & I did find replacements, just not sure on the class of bearing required.

I can pull the armature out easily without having to mess with wires so it's easy access later. I'll go ahead & check the other bearing P/Ns later on & if they're available I'll replace them regardless. That rear bearing was just the shielded type & I'll probably go with the sealed type to help keep out the dust.


----------



## chips&more (Sep 5, 2014)

When I said a little cleaning and fresh grease, I was referring to saving/reusing the one(s) you have. I have had pretty good luck with removing the seal(s), cleaning and then new grease in the old bearings. The hardest part is trying to save the seal for reuse. I put on an eye loupe and grab a jeweler’s screw driver and ever so carefully find the easiest spot to pry on. You will disfigure the seal a bit, but again with careful attention it can be straightened out. If the seal is too far gone, I have successfully made new ones out of Delrin and put that side of the bearing on the least affected when installing. And I do not clean bearings anymore in my ultrasonic cleaner! I know this sounds kinda screwy! And I could be getting slammed for it. So, maybe read up on the NET first. I ruined a set of no longer available Levin 3C head stock bearings because of it. I will never use an ultrasonic cleaner on bearings again!!!!! I use solvent in a spray can, only!


----------



## darkzero (Sep 5, 2014)

Thanks for the tips, I do have an US cleaner so I'm glad you mentioned that. I never tried removing the metal shields before only the rubber ones. I was thinking to get some replacments with the rubber shields as they should do a better job at keeping grit out.


----------



## chips&more (Sep 6, 2014)

That universal motor spins at a very high speed. Not sure if a “contact” type seal can hold up to the motors RPM? Please double check the bearing specs on max RPM for bearings with the rubber or contact type seals…Good Luck.


----------



## Stonebriar (Sep 6, 2014)

I always look forward to seeing a thread you start. Your pictures and explinations are always excellent.

Rick


----------



## darkzero (Sep 6, 2014)

Stonebriar said:


> I always look forward to seeing a thread you start. Your pictures and explinations are always excellent.
> 
> Rick


Thank you very much Rick!


----------



## maker of things (Sep 6, 2014)

I will be interested to see what this little guy can do.


----------



## darkzero (Sep 7, 2014)

maker of things said:


> I will be interested to see what this little guy can do.



Me too. As soon as I get the chance probably the first thing I'll make is a center for use on the mill. I'll post my results here, curious if the bearings are still good.


----------



## darkzero (Sep 5, 2014)

I have a couple of 2.5" micro chucks that I wanted to grind the jaws on,  also wanted to make some centers. So I tried some tests (OD grinding)  with a Dremel mounted on the tool post. Didn't like the results at all,  no surprise there. I guess I could have mounted it more securely but  didn't bother trying any further. Seems like other people do have luck  with Dremels on small lathes.



(Not actually grinding here, took this pic when I first got the lathe test fitting my Dremel holder from my 8x14)






Then I bought one of these cheap pencil die grinders. Planned on making a  boring bar style tool holder to mount it. Figured it would be less flex  than a plastic Dremel body & would do what I needed.






Luckily I never got around to it. I found a baby Dumore locally for  pretty cheap. It's their smallest model, 1/14 HP! Haha. Should be ok for  what I need though hopefully.






But it needed a little care. Not sure why but someone spliced into the  power cord & added a second switch. Both switches are functional,  need to turn on one to activate the other, perhaps a safety they had in  mind? The cord had seen it's days too, dry rotted & ground pin  broken off.






Disassembled it and found that the original switch had a hole in it.  Thought maybe that was the reason for the second switch but the original  needed to be flipped to power it up. I tested it numerous times &  it works fine but I decided to replace it anyway while I have it open.  Also got a new grommet for the new power cord.











But before putting it back together. Someone had ground down one of the  alignment pins. I pressed the pins out, cleaned them up on the lathe,  & was able to reuse them. Also slightly lapped the spindle assy's  mating surface to remove any high spots just in case.











Pressed the pins back in with my 3 ton arbor press that I got recently.  J/K of course, I no longer have the small one but the pins only required  light taps with a hammer anyway.








Now it's ready to go back together. Got rid of the butt connectors &  soldered the connections. Also added a rubber toggle switch boot for  the heck of it.





Machined a new T-nut for it. (Reminds me of when Barry first did my Dorian one)






It came with 2 belts, extra arbors, extra crowned pulleys & some  wheels. It can do ID & OD. I'll probably end up buying new stones  later anyway. I ordered a couple of new belts from Sopko but haven't  tried them yet, the old belts seem to be ok still. I still need to make a  simple holder for the diamond dresser I picked up. Can't wait to do  some testing with it.


----------



## chips&more (Sep 5, 2014)

Lookin good! Didn’t read or see anything about yah poking around at the bearings at the business end. I would highly recommend the bearings be looked at. That power cord is a sign of its age and grease dries up with age as well. Especially the grease that was made before synthetics showed up. A little cleaning and fresh grease can be a good thing/insurance. And if there is anything left of my memory???? I seem to recall that the motor bearings are hard finding or not available anymore? Hope the bearings in your motor are OK. Again, recalling on my memory??? If you need motor bearings I think you will be finding a smaller bearing and making a bushing?


----------



## darkzero (Sep 5, 2014)

Thanks for the recommendation. I did think about the bearings as I hear that's a common problem on these old grinders. I only took a picture of the real motor bearing since Iit was exposed. It didn't feel gritty nor did the others. I would like to replace them though for good measure. That rear bearing was a ND 77037 (off the top of my head) & I did find replacements, just not sure on the class of bearing required.

I can pull the armature out easily without having to mess with wires so it's easy access later. I'll go ahead & check the other bearing P/Ns later on & if they're available I'll replace them regardless. That rear bearing was just the shielded type & I'll probably go with the sealed type to help keep out the dust.


----------



## chips&more (Sep 5, 2014)

When I said a little cleaning and fresh grease, I was referring to saving/reusing the one(s) you have. I have had pretty good luck with removing the seal(s), cleaning and then new grease in the old bearings. The hardest part is trying to save the seal for reuse. I put on an eye loupe and grab a jeweler’s screw driver and ever so carefully find the easiest spot to pry on. You will disfigure the seal a bit, but again with careful attention it can be straightened out. If the seal is too far gone, I have successfully made new ones out of Delrin and put that side of the bearing on the least affected when installing. And I do not clean bearings anymore in my ultrasonic cleaner! I know this sounds kinda screwy! And I could be getting slammed for it. So, maybe read up on the NET first. I ruined a set of no longer available Levin 3C head stock bearings because of it. I will never use an ultrasonic cleaner on bearings again!!!!! I use solvent in a spray can, only!


----------



## darkzero (Sep 5, 2014)

Thanks for the tips, I do have an US cleaner so I'm glad you mentioned that. I never tried removing the metal shields before only the rubber ones. I was thinking to get some replacments with the rubber shields as they should do a better job at keeping grit out.


----------



## chips&more (Sep 6, 2014)

That universal motor spins at a very high speed. Not sure if a “contact” type seal can hold up to the motors RPM? Please double check the bearing specs on max RPM for bearings with the rubber or contact type seals…Good Luck.


----------



## Stonebriar (Sep 6, 2014)

I always look forward to seeing a thread you start. Your pictures and explinations are always excellent.

Rick


----------



## darkzero (Sep 6, 2014)

Stonebriar said:


> I always look forward to seeing a thread you start. Your pictures and explinations are always excellent.
> 
> Rick


Thank you very much Rick!


----------



## maker of things (Sep 6, 2014)

I will be interested to see what this little guy can do.


----------



## darkzero (Sep 7, 2014)

maker of things said:


> I will be interested to see what this little guy can do.



Me too. As soon as I get the chance probably the first thing I'll make is a center for use on the mill. I'll post my results here, curious if the bearings are still good.


----------

