Resurrecting an old #2 Cincinnati cutter grinder

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Harold_V
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Resurrecting an old #2 Cincinnati cutter grinder

Post by Harold_V »

When I was in training, I was assigned to a #2 Cincinnati Cutter Grinder for a brief period. Not nearly long enough to acquire any usable skill, however, as I was quickly promoted to precision grinding, where I remained until I left that job. It became obvious to me that a tool and cutter grinder would be a rather nice machine to add to one's shop, a thought I have entertained since my retirement, although I had little hope of doing so.

Fast forward to a few years ago, when Russ Hanscom (a close friend and member of this board) paid a visit to Washington State. He announced that he intended to pay a visit to a used machinery dealer north of me, and I was invited to go. The time and date was set, and Susan and I made the drive north, meeting Russ and Patty at the dealership, where I was pleasantly surprised to find three old #2 cutter grinders. The owner suggested that they had been on hand for quite some time, with little interest being shown by his customers. I made what I thought was an unreasonable offer for one of them, but I left without a deal that day. Russ had another visit scheduled in the near future, at which time he concluded the deal for me. I drove up to pay for and load the machine.

We were still building when the machine was purchased, with the shop overflowing with not only my machine tools, but our living space as well. The shop was our home until we finished construction of the house. I stored the grinder, which was sitting on a pallet, in the garage attached to the house, where it remained until we completed the house and moved in. With our furniture now removed from the shop, space for the grinder was created, so it was moved to the shop. It was placed where it will live, and ignored while I pursued other projects.

I recently turned my attention to the machine. It appeared to have been used in conjunction with spray mist, and was, without a doubt, the dirtiest machine I have ever encountered. That, more or less, gave me reason to do some dismantling, if for no other reason, to clean areas that otherwise would not be accessible. In that process I discovered a few hard facts. One of them was that the screw and nut assembly were in need of attention, as were the two rapid traverse levers, which were worn enough to be sloppy.

Buying parts for this machine is not in the cards. It was built in 1943, a war machine. Very little is available, although I did manage to find a new nut on Ebay. It was priced well over $400, and would not really address my problem, as the screw itself was worn. After some thought, I decided I could repair the existing nut, re-cut the screw, and re-bush the housings for the rapid traverse handles.

I started the process by re-cutting the original screw. The major diameter was reduced by .030", then the thread (5 pitch Acme, 1" diameter originally) was re-cut until the screw had a uniform pitch diameter full length. The screw was now a bastard, but that didn't matter as I would fit the nut to the screw, which would still be of proper lead so the dials would read faithfully.

The nut was bored out, with a pair of shouldered bushing pressed in. By providing a shoulder on each one, the nut could accept thrust in both directions without fear of the bushings moving. The nut was then bored to size and threaded. The shank had to be a right angle to the thread in order for the screw to not bind, so I made a face-plate setup using a V block to ensure the angle, and single point threaded the bushings. I am well satisfied with the results, as the dial displays only four thou backlash. I suspect the nut/screw assembly will serve perfectly well.

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The rapid traverse levers are used to propel the table for longitudinal grinding. Fast movement is desirable when grinding, as it limits over-heating (burning) the work. That's quite important with tool and cutter grinders that run without coolant. As I wanted to restore the fit to eliminate the slop that was apparent, I decided I'd regrind the two shafts, then bore, bush, then bore to size according to the resulting diameters of each shaft. My Overbeck grinder is a rather small machine, and it barely accommodated the shafts, but they turned out quite nicely and would serve their purpose perfectly. Each had a different amount of wear, so they did not end up the same diameter, which, again, is of no consequence because I would bush and bore accordingly.

The nut for this machine is made of cast iron, as are the bushings for the rapid traverse levers. I chose to use some commercially purchased ductile iron to repair them. Ductile offers the same degree of lubricity and wear characteristics as does gray iron, with the added benefit of greater tensile strength. I set about boring the original bushings, which are about 6" in length, so I could fit bushings that would provide a reduced diameter, to match the two shafts. Once pressed in place, the units were held in soft jaws (to guarantee concentrictiy) and bored near the desired finish size. I used the Sunnen hone to fit each shaft. It's nothing short of amazing how one can achieve such nice fits when the proper equipment is at hand.

The machine, being a war machine, never had what might be considered an outstanding finish. It had been repainted at least three times, and was filthy dirty and chipped in random places. Small divots were never filled when the machine was made, and I wanted it to look a little better, so I decided to hand strip the entire machine. Not as bad a job as it may sound. Using a variety of narrow scrapers, I chipped the paint off down to the original primer, which was rather robust, and released the attached paint readily. I used a little Bondo in a half dozen places, and filed it smooth. A once-over with some sand paper and files and the machine was ready to be masked for painting.

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When I acquired the machine, it came with several accessories, but only the centers were complete. The indexing head, which is necessary for sharpening the faces of end mills, lacked the indexing pawl and bracket. The air spindle lacks the required bushings. No adjustable finger was included, which I will make, along with the missing parts for the indexing head and air spindle.

The table can be locked in position by two means. One of them is the spring loaded stops at the front of the table. The other is a set of locks on the spindles of the rapid traverse levers. The left hand spring loaded stop was missing, as were the two locks. I have already made replacements, pictured here.

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New bearings were installed in the motor and spindle, with a new belt and dust cover on the column. The ways were found to be in quite good condition, so they were simply stoned well. All bare surfaces were hand sanded to restore some of the original luster. I have yet to re-machine the motor pulley, which will require me to wire and install my tracer. The pulley has two diameters, each with a crown which serves to keep the flat belt running on location.

I didn't take any pictures of the machine before I started dismantling. How I wish I would have! It would have been invaluable to have at least one, to represent the mess with which I started. I did have presence of mind to take a picture of the indexing head while positioned on the painted machine, however. It will have to serve as a representation of how dirty the machine was.

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At this point I have dismantled the indexing head for cleaning and painting. It will get painted, along with the power panel, and then I'll address the balance of the needed parts.

H
Wise people talk because they have something to say. Fools talk because they have to say something.
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liveaboard
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Re: Resurrecting an old #2 Cincinnati cutter grinder

Post by liveaboard »

Fantastic work Harold; I wish you many years of happy grinding with that machine after you finish the renovation.
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NP317
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Re: Resurrecting an old #2 Cincinnati cutter grinder

Post by NP317 »

I really enjoy seeing a machine restored and returned to service.
Nice work Harold, as always.
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BadDog
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Re: Resurrecting an old #2 Cincinnati cutter grinder

Post by BadDog »

Very nice. Far nicer than my typical refits (the term restoration is too generous). I'm also finishing a much less ambitious war machine refit on my G8. I had it just barely functional quite some time ago (mainly just to verify what worked and what needed) but then it got put aside until this summer. Sadly, I'm now awaiting custom abrasive belts to put it into full rotation.
Russ
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Harold_V
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Re: Resurrecting an old #2 Cincinnati cutter grinder

Post by Harold_V »

I have been slowly working on getting the cutter grinder operational. I have yet to place the machine and wire it, as I'm going to remove the screw and recut some locating surfaces so I can eliminate unwanted clearance on dials and handles, the result of wear from years of use. I want to do that before placing the machine where it will live, as there's a heavy cabinet that would make removing the screw difficult, if not impossible. Mean time, I have the controls painted and installed and have addressed the indexing head. It had been abused to some degree, as the indexing ring has experienced deep grinding on both sides, around its periphery, likely in an effort to create clearance for some grinding operations. The grinding of which I speak can be seen in the last photo, with similar, but smaller, grinding on the opposite face. I'm not happy with how it looks, so I'm going to make a new one, plus I must make the bracket and pawl for the indexing pin, as it was missing from the head.

I think it turned out quite nicely.

H
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Wise people talk because they have something to say. Fools talk because they have to say something.
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liveaboard
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Re: Resurrecting an old #2 Cincinnati cutter grinder

Post by liveaboard »

Wow, art meets machine!
Beautiful.
Patio
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Re: Resurrecting an old #2 Cincinnati cutter grinder

Post by Patio »

Nice job Harold!
Live for the moment!
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Forgive the past!
Patio
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Re: Resurrecting an old #2 Cincinnati cutter grinder

Post by Patio »

I got a chance to go see Harold this weekend. His cutter grinder looks better in real life than the pictures. Here are a couple more, that I took while I was there.
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Live for the moment!
Prepare for tomorrow!
Forgive the past!
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neanderman
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Re: Resurrecting an old #2 Cincinnati cutter grinder

Post by neanderman »

Stunning, as always, Harold!

We are truly blessed to have you here.
Ed

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