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New Diamond M-20. Learning the basics.

bonemech

Plastic
Joined
Jan 18, 2019
I just picked up a Diamond M-20 horizontal mill. Seemed like a good deal and was about 10 minutes from home - hard to beat! Excited to get started and have read all the posts I can find on this site and others. Ordered a set of B&S #9 collets which should arrive soon. Machine seems sound. All looks stock except the Baldor 1hp motor. Also the mounting of the motor looks like it has put undue stress on the pivot arm and bent it slightly. Would welcome any thoughts on how to restore to full function from those here who have the machine. Also, have seen a few posts that mention a vertical head attachment made by Diamond as well as Rotex options. I'd love to find a way to have both horizontal and vertical capability.

First mill and brand new to the group, so if I seem green, please guide me. Mostly will be used for making parts for older autos - currently an old jeep. Sorry for the sideways pics, took a bit to get them to show correctly and couldn't find a way to delete the sideways ones.

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Well, the motor had a bent shaft, so new one on the way. So far, mostly in good shape. Bearings in the primary drive shaft (not the main shaft) are bad and have worn into the shaft. Appears to be a dual sized, keyed shaft. Have not been able to find anything similar locally. Thoughts on building up vs having one made? Looks like it will be a bit more work to get up and running than originally anticipated.
 
Well, the motor had a bent shaft, so new one on the way. So far, mostly in good shape. Bearings in the primary drive shaft (not the main shaft) are bad and have worn into the shaft. Appears to be a dual sized, keyed shaft. Have not been able to find anything similar locally. Thoughts on building up vs having one made? Looks like it will be a bit more work to get up and running than originally anticipated.

Just get a lathe :)

allan
 
Agreed with Allan: Make a new shaft. If you try building up the worn shaft, you will likely wind up chasing your tail as welding will cause the shaft to bend or wind up with a bow (or two), or a dogleg if you build up close to one end. Sometimes, a bent shaft can be reasonably straightened using "flame straightening". This requires an oxyacetylene torch with a brazing tip to put a concentrated heat (usually to a dull red heat in dim light) in one area and using either water or compressed air to cool the area that had been heated. This shrinks the area which had been heated and can draw a bent area back to straightness. It requires a bit of instinct or a gut sense, a good eye, and patience. For something like the shaft on your Diamond milling machine, I would just get a piece of something like Stressproof 1141 shafting steel and make a new shaft. Stressproof is quite strong, machines beautifully, and is manufactured with a drawing process to create a grain structure that allows all manner of machining without distortion. Cold Rolled Steel is not what I'd use. If you machine "assymetrical" parts from cold rolled (such as milling long keyways), cold rolled will "self relieve" and distort. Make a new shaft, make sure to put fillets (radius's) where the shaft changes from a larger diameter to a smaller one, and the mill will be fine.

The weight of the Baldor motor was unlikely to cause the bending. In the era that your milling machine was manufactured and first used, electric motors were considerably heavier than that Baldor motor. Someone mis-handled that mill in moving it: could have ran into it with a forklift, or rigged it improperly to lift it. Bent shafts such as you describe do not happen due to an overly-heavy motor.

John Oder is correct: when you own and work with old machine tools, you can expect to "reverse engineer" and make parts for those old machine tools. If you do not have a working milling machine, make two shafts instead of one. Install the first shaft using shallow drillings in the shaft for setscrews in the pulleys to seat into. Use the mill to machine the keyways in the second shaft. Then, swap out the shafts so the one with the keyways gets used in the milling machine permanently. Use the original shaft as a model to take measurements off of to make the new shafts. It all plays into developing skills in machine shop work, and these include what we call "reverse engineering", designing a new part to fit where the original is either damaged beyond repair or simply missing. Setting up a milling machine to cut a keyway in a shaft is a basic exercise and will teach you quite a bit in the process. Plenty of keyways were cut on horizontal milling machines before vertical milling machines became commonplace.
 
Thanks

Thanks for the insight! Looks like I'll be "easing into" making parts. Sounds like an adventure!
 
Well, been tearing it down and finding plenty to fix. The "drive shaft" is definitely not stock. Bearings are/were metric 5203Z 17mm ID x 40mm OD x 17mm height. Shaft appears to be 13/16 where the variable pulley sits, 5/8 on the end where the large pulley goes and was probably 17mm initially where the bearings were, but now really worn down there. Does anyone know the original bearing size for these? Seems like I could make a shaft 13/16 almost the whole length except the last 3 inches at 5/8 for the large pulley. However, finding bearings with 13/16 inside diameter that fit inside the bearing covers (measure about 1 9/16) may be tough.

Looks like the "main shaft" is in good shape. Bearings have been cleaned and with some new grease will be fine.

Attached are pics of the "drive shaft" and one bearing that is less worn out. The other one is in pieces. I'll post more as I get it cleaned up a bit. 70 years of oil and grease isn't exactly just wiping off.

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I would have thought that a machine built in Los Angeles in the 40s would be all standard sizes. Not the case?
 
Ball bearings were originally a European design/product so normally made in metric dimensions ,unlike taper roller bearings ie Timken which were made to USA inch standards.
 
Wow! Would not have expected that. Makes it easier to find the bearings though. The new shaft will be a mix/match then. 17mm -> 13/16 keyed -> 17mm -> 5/8 keyed. Shouldn't be too tricky.
 
Just get a lathe :)

allan

Found a couple smaller lathes locally. Logan 1875, Vintage 1936 Southbend 9"x4', and a Craftsman 12/36. Searching around looks like Craftsman is not best/stiffest lathe nor most durable, but he has it listed for $500. Southbend is even more vintage than my mill, but looks solid. Sounds like they were/are well built. No tooling. Wants $1100. Logan looks to be in best shape and comes with some tooling, but wants $3950.
 
bonemech, I'd be happy to help you out if you're not too far in the hinterlands of Utah. I live in North Utah County and work in the Salt Lake Valley. I've got a working lathe and another undergoing restoration as well as a mill. Good deals on lathes here can take a while.

Craig
 
bonemech, I'd be happy to help you out if you're not too far in the hinterlands of Utah. I live in North Utah County and work in the Salt Lake Valley. I've got a working lathe and another undergoing restoration as well as a mill. Good deals on lathes here can take a while.

Craig

I live in bountiful. Craig, do you work at LDS Hospital? If so, we already know each other.
 
I'm a geologist out at the big hole on the west side of the valley. I took up machining about 10 years ago to support a drilling business I had. Now, thoroughly infected with Old Iron Disease, I constantly scan ksl.com for old machines to fix up. I'd be happy to help with a shaft unless your able to get your own lathe soon. Send me a private message and I'll get you my phone number.

If you look up clemwyo on YouTube, there are some videos of work I've done on my lathes and K&T mill.

Craig
 
Progress?

Well, made a shaft that seems OK after two attempts. Probably will make a nicer one later. Decided while I was fixing things I would tear the whole thing apart and clean it up. Nice restoration project. Can’t seem to post pictures from the phone so I will post them from the PC in a bit.

Any recommendations for a good gray paint that will look nice?
 








 
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