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  1. M

    OT trying to understand a very simple DC motor circuit

    I have a little machine which has a DC motor with separate armature and field windings. The machine runs on 120V AC let's call that L1 and L2. L1 goes to one side of the armature and the other side of the armature goes to one side of the field and the other side of the field goes to a 300 ohm...
  2. M

    how about glycerin as a replacement for light grease or oil?

    I read an old book about repairing regulators. Like every such book I've read, it says use no oil. Unlike any other, though, this book says you can use glycerin (aka glycerol aka glycerine) to lubricate regulator handle threads. I cannot argue with that, but I believe some might. I'm actually...
  3. M

    ISO 5hp single phase motor

    Back in the oughts, I converted a Quincy 325 from 3hp to 5hp. I bought a new Leeson single phase motor from a local rep after picking it out on the Leeson website. Now I want to convert a Champion to 5hp single phase. Naively, I thought I'd do the same thing. Not so. No local reps. Web site now...
  4. M

    Milwaukee 8600 tapping gun

    I picked up one of these tools today. It is complete including the chuck wrench and the cord is in good condition. The tool seems to work perfectly. It is a Milwaukee model 8600 but it was made in W. Germany by AEG. Here is a very short video: I know that pricing varies with different markets...
  5. M

    new plate, went all in on cheap plywood cover

    I am no carpenter. I hate buying wood. I recently bought a super clean Precision Granite 24x36x4" surface plate on factory stand. It is in excellent condition, better than any other surface plate I've owned. Anyway, my shop is multipurpose enough so that the dust can be somewhat abrasive. I plan...
  6. M

    15 hp RPC struggles to start 7.5 hp 3 phase air compressor - add cap?

    I have had my RPC up and running for ten years or so without a hitch. Confident, I decided to rebuild a 3 phase air compressor despite persistent rumors they can be hard to start with an RPC. I spun it up today for the first time. It started fine with the tank empty. (There is no pressure gauge...
  7. M

    surface plate cleaner - Windex vs lighter fluid

    I have taken two scraping classes. In one I was taught to use Windex to clean surface plates. In the other I was taught to use lighter fluid. Both teachers were eminent luminaries in their field, loaded with unassailable wisdom and experience. Both ways seem to work. I got what I really hope is...
  8. M

    nobody wants my 36x36" surface plate, what to do?

    I have an old plate with 4 ledges. It's 36x36" and 8" deep. It has some dings less than 1" and not that many, and it is flat to .0005" according to the guys who last relapped it. It's just too big for my shop, and now I've found the 24x36" plate I really want, I want to get rid of this one. It's...
  9. M

    460 only motor question

    This is a pretty dumb question, but for me college was a real long time ago, so here goes. Generally speaking, does a 5 hp motor wound for 460 VAC only have less copper than a 5 hp motor wound for 230 VAC only? Or the same, or more? Why? metalmagpie
  10. M

    lenses in old gas regulators

    A friend gave me some scrap brass yesterday. Included were two old regulators, the kind that screw onto gas cylinders. One is a real nice Victor VTS-400, a two-stage regulator with what looks to be an original green paint job. I'm quite familiar with oxygen cylinders. There doesn't appear to be...
  11. M

    air compressor pipe head to tank, is this copper ACR?

    I am resurrecting an air compressor, putting together parts from various sources. The air pump is a Champion R30A which I did a valve and ring job on. It came to me mounted on a 120 gallon horizontal tank which failed hydrotest. I found an 80 gallon Kellogg-American ASME vertical tank which did...
  12. M

    flood coolant end of life?

    I run flood coolant on my surface grinder. I put fresh coolant in a couple of years ago. I haven't topped it up but since I've read up on it, I will do that from now on, testing with pH strips or my refractometer. The one question I have is how do I know when the coolant needs to be changed...
  13. M

    wiring compressor with HOA switch, magnetic contactor and no-volts release

    I am putting together an air compressor. Its motor is 7.5hp 3 phase 240 volts. I have a size 1 magnetic contactor which has several auxiliary contacts both NO and NC. I also have an HOA switch and a pressure switch for the tank. I have seen diagrams of a normal 3 phase HOA (hand-off-auto)...
  14. M

    hydraulic unit (full) keeps popping the overload on the mag switch

    My grinder is a K.O. Lee S718HG from the late '70s. It gets occasional use. I'm doing a small job right now and right in the middle of it the hydraulic unit shut off like I'd turned off the switch. Eventually I figured out the mag switch and pushed the reset button on one of the heaters and...
  15. M

    sealing new sight gauge in compressor crankcase?

    I am going through a Champion R30 air pump. I haven't found too many issues yet other than general wear. However, it is clear that the oil sight gauge (fill to this line) has been leaking for a long time. Not only was there oil below it, but the paint had been worn away by all the oil trickling...
  16. M

    regulator repair question

    Like others, I have been using an acetylene regulator to run a propane burner. There used to be a torch and regulator repair shop in North Seattle. I knew the owner and had for several decades. He is very experienced and did all of the regulator (and torch) repair work for most of Seattle's...
  17. M

    7.5hp compressor build, am I trying to do too much?

    We all use compressed air. So do I. I've wanted to upgrade my compressor for awhile. I found a donor compressor which was someone else's uncompleted project and bought it. It's got a Champion R30A air pump (4 piston, disc valves, splash lubricated), 7.5hp motor, Square D pressure switch, and a...
  18. M

    horizontal air tank inspection ports how to remove plugs?

    120 gallon tank made in the '70s. Not ASME. It has two 2" inspection ports that are plugged with 2" pipe plugs. I got one loose but the other one will not budge. I'm posting to get help. Normally I use tanks like this to make meat smokers and I just cut out the inspection ports with a plasma...
  19. M

    any way to straighten 2 stage compressor intercooler fins?

    I have this old air pump I'm considering refurbishing. I sure don't want to go buying new intercooler pipes. The fins on these intercooler pipes aren't too bad but lots of fins need straightening. I have seen those combs they use on automotive turbo intercoolers and those aren't going to cut it...
  20. M

    new belts on old machine, very short silent video

    I've been working on this one for about a year and a half in my spare time. Tonight I put on two endless belts I got from Dave Winquist. The belt material is Habasit F-1 and he is selling it for a deep discount because he has a pile of it to get rid of. You can see him talking about his flat...

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