Support for PM90

KEW · Feb 3, 2007

I have really come to appreciate my old PM90. Despite only offering 12" swing, the lack of EVS, and no sliding headstock; the sheer mass and structural integrity of this beast make it a good, smooth machine to turn on.
However it has one critical failing - The old sheet metal stand is fairly quick to wobble if I am turning a heavier, out-of-balance blank.
I am looking for ideas on how to better stabilize the lathe.
My wife has plans for us to move to a different house before too much longer, so I would rather not pour a concrete pad.
Happily, the lathe is too short for me so this offers the opportunity to raise the lathe while adding to the footprint.
Does anyone have any ideas or experiences improving one of these older sheet metal style stands?

odie · Feb 3, 2007

KEW.....

Since you're planning on moving anyway, you might want to try using some sandbags. It would be a quick and cheap way to add some stability.

I'm assuming your lathe doesn't now sit on concrete. If it did, I'd suggest bolting it to the floor. That's what I did with my Woodfast lathe.

With all these new lathes coming out in 20" to 24" capacity, my old 16" Woodfast seems small, too!.....but, when you consider that you seldom run across good turning prospects that are big enough to make 20 or 24 inch pieces a realistic objective....my lathe doesn't seem inadequate at all. The huge capacities now available seem great, but I have little desire to upgrade.

.....odie

GeorgeH · Feb 3, 2007

I haven't seen a PM90 so I don't know how much bulk you're faced with but I do use one of those sheet metal bolt together lathe stands for my Delta LA200 and it works great. I stiffed it up by bolting a full length/width "one by" on the top and further stiffened it with a plywood shelf about mid point between the floor and the top of the stand. That was enough to take care of my needs. But, if I needed to stiffen it further, I could bolt on sheets of plywood between the splayed legs. I don't think my stiffening pieces would help much if the stand didn't have splayed legs. Straight leg stands don't seem to want to behave themselves, regardless of how much help they are offered.

MichaelMouse · Feb 4, 2007

Stiffening is the answer. You can set a 1" pole in concrete, but it's still a 1" pole, and can't take the strain 4' up on the other end any better than before. Put a brace or two at the proper angle and even it will do, however.

I advocate sheet goods for lathe stands. Glued and screwed and braced properly, they can stand up to the out-of-balance condition of spinning wood by geometry alone. You're trying to avoid flexible collisions, not "dampen" them. Turned for years on the image of the PM 90, and a wide footprint fully gusseted was all that was required.

You really want to see some cheese, you should compare the old heavy gage Delta/Rockwell equipment sands to the Grizzly interpretation. Jointer stand would twist if you had a heavy 2x8 on it.

KEW · Feb 4, 2007

I probably should have provided more background info on this lathe for those unfamiliar with Powermatic's older models. This was a common lathe in industrial and school shops for many years. The lathe manual gives a shipping weight of 700lbs. I got lucky and came across one with a jack shaft and a low speed of ~280RPM (400 to 600 was more typical).
The base is enclosed sheet metal with a cabinet under the headstock. Unfortunately the stance from front to back of the base is only 17" and either the bottom of the base, or my garage floor is not so flat as it ideally might be.

Thanks for the input, I can probably use sheet goods to broaden the stance and elevate the lathe while bolting it down.
How would you bolt it into the concrete? Would tap-cons do the job, or would I need to go with red heads? One concern I have is not knowing how thick my pad is. My house quality is not as good as I am used to - reflective of the housing boom where contractors make it look good (no oversight from a homeowner or understaffed building inspectors) and move on to crank out the next house. I don't know much about bolting into concrete and would appreciate what direction you might offer.

odie · Feb 4, 2007

KEW said:
I probably should have provided more background info on this lathe for those unfamiliar with Powermatic's older models. This was a common lathe in industrial and school shops for many years. The lathe manual gives a shipping weight of 700lbs. I got lucky and came across one with a jack shaft and a low speed of ~280RPM (400 to 600 was more typical).
The base is enclosed sheet metal with a cabinet under the headstock. Unfortunately the stance from front to back of the base is only 17" and either the bottom of the base, or my garage floor is not so flat as it ideally might be.

Thanks for the input, I can probably use sheet goods to broaden the stance and elevate the lathe while bolting it down.
How would you bolt it into the concrete? Would tap-cons do the job, or would I need to go with red heads? One concern I have is not knowing how thick my pad is. My house quality is not as good as I am used to - reflective of the housing boom where contractors make it look good (no oversight from a homeowner or understaffed building inspectors) and move on to crank out the next house. I don't know much about bolting into concrete and would appreciate what direction you might offer.

I've bolted my equipment to the floor a couple of times (moved once). I probably don't know the proper names for these things, but what you'll need is a hammer-drill and some cement anchors. You can drill a hole in cement by hammer and your muscle, but that's the hard way! I did that once.....never again! If you don't have a hammer-drill, most rental yards have them.

Make a hole in the cement to the proper size. Drop in the anchor and a standard bolt will screw into it......nice and solid.

Just about any hardware outlet has the cement drill bits and anchors.

....odie

KEW · Feb 6, 2007

Thanks. I know the hardware you refer to. Maybe called wedge-anchors or something like that.

odie · Feb 7, 2007

KEW said:
Thanks. I know the hardware you refer to. Maybe called wedge-anchors or something like that.

KEW....

Yeah, I think you know what I mean. I think they're made out of some sort of lead alloy.....they are cast from fairly soft metal. Anyway, they have a split down the center and when the bolt is screwed into them, they expand into the hole in the cement.

good luck

....odie