Delta Milwaukee Toolmaker Grinder owners

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earlgo
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Delta Milwaukee Toolmaker Grinder owners

Post by earlgo »

Unfortunately I have an OOOPs, OH _____! to report. I have had a DM TM Model 24-105 since 1988 and who knows how old it was before I got it. Yesterday when I was using it, the head/motor/wheel assembly crashed down on the mag chuck totally unexpectedly. Fortunately I was just adjusting the head height and did not have the wheel running.
wheel crash
wheel crash
It turned out that the Raising nut had worn so much that the id threads were sheared off by the weight of the head. One can see from this pic that there are thread remnants in the raising screw (10TPI Acme).
Acme Rod
Acme Rod
Pic of the Nut Thread remains.
Raising Nut
Raising Nut
I don't know if the spindle bearings were damaged or not, but the head didn't fall more than 3 or so inches, so I am guessing not.
This is just a warning to those of you who have an older machine. It 'might' be good maintenance to look at the nut every few years to fend of a crash like this. No fingers were hurt but it would have been very painful if they had been in the way.
--earlgo
P.S. Now I have to make a new nut before I continue with my project, but first I have to grind an Acme internal threading tool, but first I have to buy material, etc, etc per Washington's principle.
Before you do anything, you must do something else first. - Washington's principle.
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Harold_V
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Re: Delta Milwaukee Toolmaker Grinder owners

Post by Harold_V »

That's interesting.
I recently restored an early Cincinnati #1 cutter grinder. The screw/nut assembly for the cross slide was worn badly, with the nut pretty much trashed, although it did still function.

It stands to reason that if there was enough wear on the nut to fail, the screw, too, had issues. A new one was not an option, so I made a setup and chased the existing Acme thread until it was of uniform, although now bastard, pitch diameter. I then made a new nut to fit the thread form. It is now unique, but who cares? They match and work exceedingly well, with almost no backlash. Considering the amount of use the machine will get in my hobby shop, it should last for decades.

I made mention because you may wish to do something similar before making the new nut. I suspect the screw in your grinder isn't without similar issues. It took a little more then ten thou for mine to clean up.

H
Wise people talk because they have something to say. Fools talk because they have to say something.
Russ Hanscom
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Re: Delta Milwaukee Toolmaker Grinder owners

Post by Russ Hanscom »

Got the same problem with my Delta Toolmaker. I noticed the acme threads were more saw toothed in shape than acme. The correct size acme threaded rod is available and I have a piece ready to go. Might have even procured the tap via ebay. One of those projects I need to dust off before the failure happens,

Thanks for the reminder.
earlgo
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Re: Delta Milwaukee Toolmaker Grinder owners

Post by earlgo »

For those of you interested, here is a drawing of the Model 24-105 Toolmaker Grinder Raising Nut, part # SGC-54. I made it to accurately reflect the dimensions of the part taken from the machine.
I looked up the corresponding part on the Delta website for the Model 24-150 and 24-151. The part no is 408-01-017-5004 and price listed is $600.80. (I hope this is a typo.)
SCG-54 RAISING NUT.pdf
(98.3 KiB) Downloaded 167 times
I hope this may help someone.
Regards,
--earlgo
Before you do anything, you must do something else first. - Washington's principle.
Russ Hanscom
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Re: Delta Milwaukee Toolmaker Grinder owners

Post by Russ Hanscom »

So, I just saved a bundle! I managed the repairs as simply as possible.

The raising screw has 4" of full diameter, 3/4", unthreaded shaft, there is a key way and two taper pins retaining shaft collars, in that area. I cut off the unthreaded portion, put it in the lathe, and drilled and reamed a 7/16" dia by 1"+ deep recess in the bottom end. Having a piece of the correct acme all thread, I turned one end down to 7/16" dia by 1"+ long and pressed that into the recess in the unthreaded portion. Redrilling and tapering reaming the lower taper pin hole holds the two pieces together.

For the nut, I had a nub of brass almost the correct size required. Next drill a 5/8" dia through hole and press the nub onto a mandrel. The exterior got turned and threaded to match the original nut, then the mandrel was pressed out, and the exterior was gripped in the chuck. A bit of 3/16" square HSS tool bit was ground with the approximate acme tooth profile and then the thread was rough cut. I have a new 3/4-10 acme tap which was used for the finishing pass. The fit was a bit snug so the raising screw was gripped in the chuck and the nut was run back and forth half a dozen times until it felt free.

Now starting the reassembly; not bad for maybe three hours effort.

DSC02272.JPG
earlgo
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Re: Delta Milwaukee Toolmaker Grinder owners

Post by earlgo »

Good job Russ. I haven't been able to find a section of 3/4-10 Acme rod. Neither McM or MSC has it listed, so I am going to use the original rod and fit a new nut to it. It will last longer than I will.
--earlgo
Before you do anything, you must do something else first. - Washington's principle.
Russ Hanscom
Posts: 1955
Joined: Wed Mar 15, 2006 11:10 pm
Location: Farmington, NM

Re: Delta Milwaukee Toolmaker Grinder owners

Post by Russ Hanscom »

I bought a six ft piece of rod, used less than two ft. You can have a piece for shipping costs.
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Harold_V
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Re: Delta Milwaukee Toolmaker Grinder owners

Post by Harold_V »

Nice repair, Russ.

H
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Steggy
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Re: Delta Milwaukee Toolmaker Grinder owners

Post by Steggy »

Russ Hanscom wrote: Sat Jul 24, 2021 4:55 pm So, I just saved a bundle! I managed the repairs as simply as possible...Now starting the reassembly; not bad for maybe three hours effort.
Sure beats parting company with 600 smackers!
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earlgo
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Re: Delta Milwaukee Toolmaker Grinder owners

Post by earlgo »

Russ:
Sent a PM to get this started if you are willing, I am very grateful.
Regards,
--earlgo
P.S. I see it is still stuck in the Outbox as are two other messages I tried to send. ????
Before you do anything, you must do something else first. - Washington's principle.
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Harold_V
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Re: Delta Milwaukee Toolmaker Grinder owners

Post by Harold_V »

earlgo wrote: Sun Jul 25, 2021 2:13 pm P.S. I see it is still stuck in the Outbox as are two other messages I tried to send. ????
While most readers understand how the PM feature works, some don't.

Folks, check your Private Messages occasionally, if not daily. The way the sender knows they have been read is that they remain in one's Out Box until they are opened, at which time they then display in the Sent Box.

H
Wise people talk because they have something to say. Fools talk because they have to say something.
earlgo
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Joined: Sat Jan 29, 2011 11:38 am
Location: NE Ohio

Re: Delta Milwaukee Toolmaker Grinder owners

Post by earlgo »

Thank you Russ, for the threaded rod. A $56 chunk of 936 Bearing Bronze rod from McMaster-Carr and I will be back in business. But first, I need an Acme inside threading bit for my boring bar. :idea: No problem, I'll set up the grinder and do it.... oh, wait.. never mind. :roll:
Wonder what my friend with the shop full of working machines is doing this afternoon...
--earlgo
Before you do anything, you must do something else first. - Washington's principle.
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