# Need Help Mounting A Dumore Tool Post Grinder To Colchester Lathe



## Techie1961 (May 14, 2016)

I have a series 57 Dumore tool post grinder that I picked up recently and also fixed up a bit. Now comes the task of mounting it to my lathe. The bore in the main housing of the Dumore is 1.5". My lathe has the original rotating tool holder with cam lever on top and four positions. You can see the style in the photo of the lathe. I tried taking it apart to see if by chance, the post was the right size but it's a bit larger at 1.75". It was a pain to take apart and worse to put back so I'm kind of glad that it didn't fit.

Anyone have any ideas on how to mount this thing? Maybe I have to remove the tool slide and build something that can bring it to the correct height.

On a side note, how do you put a QCTP on this lathe? Does it go right over the post that's in the middle of the original tool post?


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## Bob Korves (May 15, 2016)

Do you have the tool post that comes with the Dumore grinder?  If so, make a t-nut for the bottom of it to fit your lathe compound if the supplied t-nut does not fit.  If you are missing the post, they are available from Dumore ($$$), or you can make one to fit.  Dumore has the parts catalogs on their web site where you can get the part number to order one or just look at the drawing, measure up the Dumore, and just make one.  Your existing four position tool post needs to be removed when using the Dumore.


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## Techie1961 (May 15, 2016)

Thanks for the reply Bob. The post is missing from the package that I bought but making something isn't the problem. The Colchester seems to not be friendly to change. I should have taken some pictures with the four position off but it seems that it's center post is integral to the tool slide upper. There isn't a T slot at all otherwise it would be fairly simple.

With the four position off, the tool slide is completely flat on top other than a 1.75" solid steel post sticking up. Have a look at the photo from my manual.


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## Chipper5783 (May 15, 2016)

That there is no T-slot is pretty common.  Perhaps you can make an adapter,  sleeve or custom nut.   Or just pull it apart again, figure out how it all goes together and make up a center bolt that works for the equipment you will mount on the compound.

I have two lathes, neither has a T-slot.  I have added a QCTP to each - in both examples I had to completely take the slide apart.  On the first lathe, I probably took the compound apart several times to check the fit.  After all I was using the lathe to make the new center bolt.


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## Techie1961 (May 15, 2016)

Thanks Chipper, I'm kind of leaning towards removing the tool slide completely (two 5/16 nuts) and making something to go on the cross slide. I won't be able to do any angles with it though. The post on the square turret is larger than the hole in the grinder base so I can't really adapt anything up there.


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## petertha (May 15, 2016)

Probably not much direct help to your grinder/lathe combination, more of an FYI. This is how I mounted my Themac. The tool post is removed, grinder clamped with a plate in the T-slot. The Themac spindle can adjustably slide on its T-slot rails attached to the motor housing to locate relative to lathe center height. I've seen some people with bigger grinders / smaller lathes remove the compound altogether & make an adapter plate that matches the compound bolt pattern. This limits you to XY-axis movement only vs. angular movement tough, as I think you've indicated.


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## Wreck™Wreck (May 15, 2016)

Mount it by any method that works, you may spend the rest of your life trying to do it "by the book" which was published in 1939.

I am constantly entertained by hobbyists that consider 60 year old books on machine shop practice as the "proper way" .

This is not to disparage but to encourage methods outside of the norm, in other words do whatever it requires to make it work even if it is contrary to conventional practice, close the old book and kick it aside.


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## Techie1961 (May 16, 2016)

Thanks for the comments wreck. I suppose that if you knew me, you would know that I am about as much NOT by the book as anyone can be.  I live and play outside the box. I'm also a tool and die maker rather than a hobbyist.

I don't have a lot of time on lathes but instead on mills, surface grinders, etc. I was hoping that I was missing something on how these usually mount up since I haven't ever used one. I think that that tool slide must be a special for Colchester only and even if I want to put a QCTP on it, I'll need something custom. Thanks again for taking the time to respond.


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## f350ca (May 16, 2016)

Is there enough material around the bore on the tool post grinder to bore it out to fit the tool post? 
The Colchester Student I had looks identical but had a conventional compound with T-slot.
Removing the compound should work but you loose the ability to swing the compound to 5.74 degrees from axial and get a fine in-feed of 10:1, nice feature I've used the few times I've needed the grinder.

Greg


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## Bob Korves (May 16, 2016)

If you are a tool and die maker, maybe make a compound top to replace the top half of the Colchester one completely when you want to use the grinder, using the Colchester bottom half for the slide, gib, swivel, and ways.  Kind of overkill, though, and it might be slow to change from the grinder to the normal compound top, but it would leave the lathe in original condition and you could use the modified compound motion to grind tapers.


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## kd4gij (May 17, 2016)

I would bet a compound from a different model like the student would fit. Some one here may have one that could take measurements for you.


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## Mark_f (May 17, 2016)

I don't know what your cross slide looks like without the compound, but I am building a tool post grinder. ( a thread on here somewhere). I remove my compound, mount the post and it will turn to any angle.


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## TommyD (May 18, 2016)

Make a "Z' plate to mount on the bung for the tool holder, keeping the center post mounted on the compound. Bore a hole in the Z plate to mount over the bung, and make a spacer and use the center post nut and washers to mount the plate onto the compound. The Z offset should be enough to put the grinder spindle on center with the lathe spindle. The Z plate and butt against the compound either on the side or front. You will need to fabricate something to mount the grinder to the Z plate.


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## Techie1961 (May 18, 2016)

Thanks guys, some good feedback on here. I don't want to bore out the tool post as I like to keep things original or at least able to return to original and that would be past the point of no return.

I like the idea of trying to find or possibly make a top slide. I think that it will come off when you feed it in all the way but not sure. The Z plate/adapter, if I am understanding the idea, would likely not work. With the post sticking up off the top of the tool slide, I can't see how I could put this on and not either be way too far back, way too far forward or too far on either side of the slide.

Does anyone know if there are slides that are mountable/universal? I was just thinking that with the tool slide off, I could put a different universal slide on it and mount the grinder to that.


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## middle.road (May 22, 2016)

Wouldn't it be possible to use the Tee Nut Slot that is on the left of the compound (chuck side)?
Or does the #57 not use a post and thru bolt like mine?
Can't tell what size that slot is though...


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## Holt (May 29, 2016)

I have a lathe like yours, I made my own QCTP, and here is how i altered the compound to accept the turret from my new system.
http://www.hobby-machinist.com/threads/home-made-qctp.44801/#post-382095


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## Techie1961 (May 29, 2016)

middle.road said:


> Wouldn't it be possible to use the Tee Nut Slot that is on the left of the compound (chuck side)?
> Or does the #57 not use a post and thru bolt like mine?
> Can't tell what size that slot is though...


Interesting idea but there would be too much to remove to make that useful. So much shaft, pulleys, etc. on the grinder. Thanks!



Holt said:


> I have a lathe like yours, I made my own QCTP, and here is how i altered the compound to accept the turret from my new system.
> http://www.hobby-machinist.com/threads/home-made-qctp.44801/#post-382095


You did an awesome job on that QCTP. Very nice work! Thanks for sharing.


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## Holt (May 30, 2016)

Thank you for that, if you haven't seen it, there is a tread about how I got and restored it to working order, in the CLAUSING-COLCHESTER & LEBLOND section. http://www.hobby-machinist.com/threads/colchester-triumph-1958-restoration.44684/


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