Delta Milwaukee Surface Grinder Rebuild Questions
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  1. #1
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    Default Delta Milwaukee Surface Grinder Rebuild Questions

    I picked up a "free" surface grinder a few weeks ago. I was buying a different machine and the guy had a pile of parts that was going to go to the scrap yard. It looked like it was all there, so I decided to take a stab at it.

    It's an old Delta Milwaukee surface grinder. I don't think it's the "Toolmaker" version as it doesn't have any of the table taper features or tooling. Once I got it all sorted out, I found it was missing some simple stuff, but otherwise could be a functional grinder again. I decided to take it on mainly as practice scraping. The ways aren't too bad, but they're all simple flat ways so it's going quickly.

    So my questions are about the motor/spindle set-up. It was missing the OEM motor and pulleys. I have another 1/2 HP sealed frame 110v Delta/Rockwell motor that would fit nicely with the machine, but I've also read that the spindle and motor need to be dynamically balanced. Is that something only the pro's can do or where would I start?

    I was able to find an OEM spindle pulley (2 speed), but am still missing the motor pulley. Short term, I'm thinking I'll use a single groove pulley and pick a speed, but to replace the 2 speed motor pulley, I think I'll need to make one. Can someone measure the diameters of the steps for me? Otherwise I can do some math and figure approximate diameters, but the original dimensions would help.

    I'm thinking about putting it together with what I have and taking some test cuts. If I get a lot of chatter, then I'll know that it needs balancing.

    As a side note: I'm fairly certain this machine was a Hurricane Harvey victim. Random places have been full of water, but 90% of the machine is rust free thanks to it not being kept very clean of grease and grime. The other 10% of exposed surfaces were heavily pitted. This included some areas of the spindle, but thankfully all of the bearing seats and the front taper bearing are damage free. But perhaps the pitting will have a play in how balanced the spindle is now.

  2. #2
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    It's the grinder itself that carries the "Toolmaker" name, whether or not it has the optional swivel table, centers, Unihead, etc. The Vintage Machinery website has most of the available literature, or you can find a bound copy on eBay.

    Mine has the OEM motor, but a replacement single groove pulley. I doubt that they were balanced together. Would I get a better finish with a balanced setup? Probably, but it is good enough for most of what I do. A good motor shop should be able to handle the balancing. Delta says the motor pulley was 5-15/32" diameter - large step, I assume - and shows speeds of 3200 and 4200 RPM with a 1725 RPM motor. As you have an original spindle pulley, the math should be easy. My motor pulley is 5". Not sure why they had the two speeds, presume it was either to keep larger wheels under their rated max, or maybe to allow you to tweak for the best finish.

    I did see an original motor pulley on eBay recently, but with a 1/2" bore. My motor is 5/8". Delta shows 1/2" in a 1956 catalog, I think mine may be older.

    There is a newsgroup just for this machine. It's a Yahoo group, but not very active.

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  4. #3
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    My understanding is that the motor and pulley were balanced together.

    Since you're starting from scratch, you might consider getting a decent (good bearings) 3 phase motor and a VFD (cheap for under 1hp). Could be handy. I suspect you could sort-of static balance the motor and pulley by seeing where it stopped. If it always stops one place down, you might lighten drill the pulley there to get it a bit closer to balanced?

    These use a non-standard wheel adapter. If yours came with more than one, count yourself lucky. None? Last I looked replacements were around $150.

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    I've got one hub for 3/4"+ wheels, It would be handy to have a smaller one for 3/8"-1/2" wheels. I've been wanting to buy a wheel balancer for our shop, but in general I try to keep hubs and wheels (on our other surface grinders) together once they're running well.


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