Powermatic 90 mods, can I make it work for what I need?

Did the search and am not finding what I am looking for. Sold a John Nichols lathe last year, hadn't used it in 12 years but stupid. Need to turn about 30 pieces 20-26" in diameter x24 tall. have a 3.5 horse leason motor that could be used. Idea is to build a new base and gap bed or dedicated bowl lathe. Will that headstock hold up to that with the proper base or am I better off building from scratch? Trying to get something quick and on a budget, the PM90 is attractive because I have a overabundance of purple heart and I can do a trade. I would be trading 100 board ft of purpleheart for the lathe, basing that on wholesale about $420 for the base PM90. Thoughts? I have tons of lumber and no cash. Kicking myself for letting that lathe loos, didn't realize what I had.

Cheers, Chris

Just from memory, which may be faulty here, but I'm not sure that the PM90 has a swing that will allow for 26" diameter pieces. You are correct it is a workhorse of a lathe, and you could consider putting riser blocks underneath the headstock and tailstock to allow for the large diameter. I have seen pics of metal riser blocks and wooden riser blocks.

Another consideration....if you are going to have 24" length in a heavy piece, cantilevered off the spindle, you will need tailstock support, IMO, so as to be able to steady things, unless you build a steady rest and have the room on the bed of the lathe to place it where it needs to be.

Even if you could turn it outboard, I do not think the speed could be lowered enough for the pieces you have in mind. IIRC it has a 1.25 spindle. I visited a guy last Sunday who turns large items, wooden patterns for old industrial flywheels, up to 4 ft in diameter. He uses a massive old gap bed engine lathe with a huge 440 volt motor. (motor is bigger than my v-8 truck engine) I am not sure how he arranged the extremely low rpms he needs. The spindle on that lathe was about 4 inches in diameter. I have seen special lathes made from I beams welded together into a lathe bed and a heavy armature with pillow blocks for the spindle and a home made tail stock made of a similar armature. Old industrial engine lathe head stocks come up on ebay, costing more for shipping than the item.

Have you considered a vertical lathe? anchor the work to a face plate turn table that turns on a horizontal plane. Use gravity to work for you and cut from a vertical tool rest or even a machine rest

If I understand your question correctly, my answer is "it might."

I owned a PM90 circa 1958 for about 10 years and got it to original condition. It was a beaut. Very, very stout. The problem I see just using the headstock and fabricating a custom bed/base for it, will be twofold: what condition are the bearings in? And what do you plan to do with the reeves drive?

the reeves drive will only let you get down to about 700rpm... maybe too fast for a 24" piece? If you are going to go the VfD route, then the point is moot.

the bearings are typical to replace but make sure you get the best quality you can. I wouldn't bet against the pm90 doing just about anything asked of it...

26" X 24" is a big chunk, what exactly are you trying to turn? Is this a one time project or something you're going to do regularly? Is it just a cylinder or is it some other from? Don’t get me wrong, far be form me to dissuade you from buying/building a big honk'n lathe, but this might be a situation were a router lathe might be the better option. Something like this link. While its showing hollow columns, you could do the same idea with a solid block between points.

http://woodarchivist.com/2035-router-cut-columns/

Mike