Restored Powermatic 90, and first bowl complete!

[Lee Alkureishi]

Hi everyone,

It's been a long while since my last project post - I've been latheless for a time after selling my Harbor Freight 34706. In the meantime, I've been working on getting my new lathe up and running - a nice old 1970 Powermatic 90. All told, it didn't need much done to it - new headstock bearings, a new machine key for the reeves pulley, new belt, and a VFD for variable speed. The original paint job was in excellent condition, as was the rest of the machine. It's now running quite nicely, except for an annoying persistent clunking from the headstock - I have a friend coming to help me troubleshoot that next week..

Meantime, I completed my first project on the new beastie - an unknown wood crotch piece that I originally cut from the log several months ago, then realized it was too big, heavy and out of balance to turn on my old lathe. It sat on the shelf until the PM90 was ready. So, here's the result!

As always, C&C welcome :)

Lee

[Lee Alkureishi]

Crotch bowl, unknown wood picked up from the tree feller's yard...
Please ignore the pink bit on the bottom - an experiment gone wrong! It'll be replaced with a little signed disk in the near future...

[Rodney Walker]

Nice job on both. I really like the figure in the bowl.
Rodney

[Russell Eaton]

Great job on the bowl and the lathe. The old PM looks great to be 42 years old.

[Roger Chandler]

Nice restoration on vintage iron.........that holds a lot of potential........I like your VFD and the fact you put it towards the tailstock end.......helps to keep dust to a minimum that might affect electronics.........hopefully the unit is a sealed one. Nice work Lee!

[Ken Glass]

You have to love old iron.... Lee, excellent job restoring a great old lathe and nice work on the crotch dunno wood. Its got great figure and colour. Well done.

[Dick Strauss]

Lee,
You did a great job on the lathe and the bowl.

The clunking sound might be a kink in the new belt or mis-aligned pulleys (where the belt jumps to re-align itself). Also, the reeves drive springs are sized to handle specific motors (let's say 1hp). If you put a bigger motor on it (say 2hp), the reeves drive might buck from not being able to handle the extra power.

You may want to install something to divert the shavings away from the top of the VFD. It should be high enough to allow air flow but low enough to clear the bed/tailstock, etc.

[Bernie Weishapl]

Great job. The lathe looks great as does the bowl.

[Lee Alkureishi]

Thanks!

Roger, the VFd is actually in the cabinet directly under the motor - it seemed like a good idea when I was doing it, but the chips do unfortunately find their way in there... I plugged the hole where the cabling exits the cabinet (directly under the headstock end of the ways), but the chips are tenacious buggers, and still find their way in.

Dick, I'm very interested to hear more on where to install the chip diverter - under the ways? In the cabinet?

Failing that, I'll extend the plywood bracket I used to mount the VFD and create a more enclosed "box" to protect from the majority of the chips. The dust, though, is another thing... At some point, I'll need to move it out of the cabinet onto the wall. But, that's a LOT of finicky wiring to undo then redo!

Thanks for the tips on the clunking - i'll take another look at it when I get home! I kept the existing motor (1hp), and it seems like it is plenty strong for anything up to the lathe's capacity. I haven't been able to slow the lathe down much, even with the VFD running at 10hz (1/6 speed!, giving a nominal low speed of 160rpm, but I'm sure it's actually lower; still waiting for my tachometer to arrive). If I get around to installing risers, I'll likely also install the 2hp 3phase motor I got for that purpose. The VFD is rated up to 2hp, and a quick test showed that it would happily run the motor. For now, though, it's just sitting on the shelf looking angry.

Thanks again,

Lee

[Mike Cruz]

Lee, funny that Dick mentioned the belt. I was thinking the same thing just now. Try running the lathe without the belt cover on. See if A) that cures the noise, or B) you can get a better idea of where the cluncking is coming from.

I would recommend taking the VFD out of the cabinet. Way too much dust (and chips) find their way in there. Mine is about 7 feet off the ground mounted on the wall above the headstock...close enough to reach the controls if I need to (never do), but far enough away that dust and chips aren't directly sucked into it.

Nice figure in that wood, too!

[Lee Alkureishi]

Hi Mike,

Thanks for the pointer. I ordered the extra cabling so I can move the VFD away from the mess :)

Without the belt cover, the noise persists. I don't think it's the belt, as both the new and old belts result in the same noise and they both seem in good condition.

I actually had a new machine key made for the spindle reeves pulley, as the old one was pretty worn and there was significant slop in the pulley. When I installed the new key, it was slightly too tall, preventing the movable "shroud" (not sure how better to describe it) that the outboard bearing fits into from sliding all the way out. I filed the new key down enough that it allowed that full range of movement, but I think I may have been too aggressive. There's still a little slop on the outboard side, and I'm pretty sure it's between the spindle, the key and the reeves pulley. The bearing has no slop whatsoever, and the shroud seems to be firmly seated in the headstock with no play.

As it turned out, once the reeves pulley was reinstalled, I realized that that shroud doesn't NEED to move all the way out; I probably could have left the key as is. I'm wondering if that would have fixed the problem... I'll attempt to shim the key with some electrical tape today, to see if that improves things... If so, I'll need to have a new key made... My friend who made the first one will be most disappointed that I butchered his first one!!

Thanks,

Lee

[Mike Cruz]

As someone pointed out to me, after I did my restoration... The good news about all this is that, in the end, you will know your lathe better than most people know theirs. ;)

[Dave Mcintire]

I had the same machine with a clinking noise in the headstock that turned out to be the squqre key in the headstock spindle was worn and loose. Its been a while and i forget all the details, but you might want to look there.

[jim f taylor]

Nice job Lee. Did you ever find a solution to the clunking sound?

Tr

[Marc Himes]

Well done on the lathe and bowl. I am at a loss when repairing machinery, so I tip my hat to you sir.

[Lee Alkureishi]

I found a temporary solution...

After much fiddling, i realized that the spindle is worn where the movable pulley / shroud slides. There's about 8/1000" of play between the spindle and the moveable assembly (including the outboard bearing). I'm convinced that's the source of the noise...]

I also realized that the old oil seal was still embedded in the headstock - i'd missed replacing that the first time around. It was in bad shape. After about an hour of futzing, i got the old seal out and installed a new seal. It was a snug fit, and took up all the slop between the spindle and the bearing. Voila! The noise and vibration disappeared!

Unfortunately, after my first catch i realized that the oil seal is not designed to be a structural support - the noise came back with a vengeance. I'm guessing the force of the catch deformed the thin metal of the seal, allowing the slop to return. But, the whole process at least showed me that the noise is related to the wear pattern on the spindle, and one of the kind pm90 owners over ar owwm has sold me a spare spindle of his for a very reasonable price - just waiting for it to arrive in the mail :)]

On another note, yesterday i managed to retrofit my 1970 pm90 with a homemade jackshaft - it's a little ugly, but should do the job nicely. It was a lot easier than i thought it would be, and the next step will be to slide my 2hp motor into the cabinet. The main reason for the jackshaft was because the bigger motor has a 7/8" shaft, and the lower reeves drive is bored for 5/8". The jackshaft solves that problem, and has the added advantage of allowing adjustments in the speed range for better torque.

I'm having fun with this, but looking forward to getting back to turning!

[Mike Cruz]

Looking good, Lee! Keep us updated on the progress. BTW, did you get the pic I sent you of the brace I had made for securing the lathe to the wall?

[charlie knighton]

great job Lee, enjoy

[Lee Alkureishi]

I did, thanks! It's a lot simpler than I thought :)

The risers are next :)

[Bill Summerlin]

Did you replace the bearings in your restoration, and if so, where did you find them?