Powermatic 90 bowl lathe - I want biggerer!

[Lee Alkureishi]

Hi Dick,

Thanks for the advice, and for the link.

I'm currently running a 2hp Leeson on my "real" PM90, using a shop-brew jackshaft with step pulleys, and it runs great. Granted, I haven't turned anything close to 34" in diameter, but I haven't come close to stalling/slowing it down either.

I'm no mechanical engineer, but the spring on the lower reeves pulley is a pretty hefty one - I had to use my drill press to exert enough downward pressure to get the snap ring off. Hopefully it'll hold up!

Lee

[Mike Cruz]

I ran a 2 hp motor on my PM90 as well without slippage. The largest I turned on that was about 17".

But it is always great to have a good source for pulleys! Hope those work out.

[Dennis Nagle]

+1 what Mike said. You won't be hanging anything off the jack shaft and if it is just as wide as two pulleys and supported on both side, you should be fine.

[Lee Alkureishi]

Hi all,

Just a quick update, as it's going to be a while before I can make any more progress with this project... New baby just around the corner!

Got the headstock all cleaned up and painted, bolted on, and the banjo finished. New bearings in the motor, hooked it up to my VFD and the mounting plate made. The belt cover in the pic is a cast iron original from my other pm90.

Still to do:

- Bolt the motor mount to the frame
- Put together and mount the jackshaft (received all my pulleys in the mail yesterday - 2.5" on the motor, 2.5" and 5.5" on the jackshaft end). I actually bit the bullet and went with a 1" shaft, to match my reeves pulley (which is originally from a PM drill press). Saves messing around with shaft adapters/sleeves and such...
- replace the speed change pin bearing
- Make a lower belt cover for the jackshaft (which will go right under the existing belt cover)
- Make a riser for the tailstock and get everything lined up (the hard part!)
- Paint the riser and repaint the belt cover
- Test!

Thanks for following along with this build - it's a lot of fun, but very slow going with work (and life!) taking priority. I've learned a lot (and worried that my welds weren't good enough - I had a real welder check it out, he said it looks ok!)

Hopefully I'll get the rest of it done sometime soon!

Lee

[Mike Cruz]

Looks great, Lee!!! Make sure you follow up with us on your progress...you know when your child is about 11 or 12...

[Lee Alkureishi]

Got the Wee Beastie up and running

Haven't had time to make her pretty yet, and the Reeves drive needs a little tuning, but... we have a working bowl lathe!

How does she run?

Well... not sure yet. Haven't had time to put some wood on it yet. But, I can say that this headstock and Reeves drive is a good bit smoother and quieter compared with my other pm90.

With the jackshaft setup I rigged up, I get a fairly decent speed range - with the VFD at 100%, it'll give 300-900rpm on the bigger pulley, and 700-2100 on the little pulley. I think the spring on the Reeves pulley is actually shot; once that's replaced, I should get 300-1200rpm and 700-2800rpm on each. Belt changes are quick, as the motor is just on a heavy hinge.

Will start a new post once I get the first project mounted Thanks for looking

Lee

Edit: obviously, I still need to make the riser for the tailstock!

[Mike Cruz]

Lee, that is just too cool! I bet you are proud as heck of that beast. You worked hard (I know!), you planned it all out, and you succeeded. Not something that everyone can attest to and achieve. Fantastic job. I really really hope she's enjoyable to turn on.

The rpms sound just fine the way they are. Honestly, if you are turning big stuff on this thing (as you intend to), say 17 and up blanks, I doubt you'll ever want to be turning at over 2000 rpm. Actually, on all my big stuff, I think 1100 is the fastest I turn...which is my medium "gear". If you can get 300-1200 on the one gear, you may never take the belt off that one or use your VFD for speed control. 300 is probably slow enough for everything from power sanding to your very largest blanks. Though, maybe some of the very largest MIGHT ask to be slowed down just a tad for beginning rough out while unbalanced.

One thing to look out for is belt slippage. You put a 2 hp on this, right? At 2 hp with a jackshaft, you will likely not be able to slow it down much. But your belts just might slip. So, make sure that they are tight enough, or at least you can adjust them to be able to be tightened...the weight of the motor may or may not be enough tension on the belt.

Man, I look forward to your next thread!!!! Congratulations!!!

[Harry Robinette]

Lee
I've been using a Vega 2600 for about 11 years or so and the way your going I think you'll have a nice bowl lathe. At 25" x 14" the 2 Hp with inverter and 3" to 7" and back pulley system it takes all of that to work that size,I think you need to look at your funding for a 3Hp motor. I do like the leg stance your using. The Vega legs are straight down from the corners and it WILL rock,I think Vega relies on the 550# to hold itself steady. Don't get me wrong I completely love my Vega but like everything it has it's own little quirks. Remember a little finesse with the pulleys and the VFD can always get you to a speed for pens.

[Lee Alkureishi]

Mike and Harry, thanks for the comments!

I think I'm going to stick with the 2hp for now. If it turns out too weedy, I'll keep my eye out for a 3hp at the local scrappy. The jackshaft gears everything down fairly heavily (2.5" to 6", then the reeves drive on top of that), so hopefully there'll be plenty of torque at the low end.

Harry, thanks for the input about the Vega - I hadn't seen that model before. I'm not sure how much mine weighs, but I can't lift anything other than the tailstock end. Even sliding it across the concrete floor is a struggle, so I'm guessing around 400lbs. If it's too light still, I'll probably add ballast to the shelves and fill the headstock riser, banjo post and legs with concrete We'll see once I get a big piece of wood on her

Lee

[Harry Robinette]

Lee
Filling the headstock riser well really help with vibration,the Vega is concrete filled and I think it's one of their best ideas. The higher up on the machine you put the weight the better the vibration damping,weight put down low will help but is better to help with a lathe thats moving around.I really want to see and hear about it running, so keep working.

[Lee Alkureishi]

I think I'll go ahead and do that - been putting it off because my welds are not 100% continuous, and it's gonna be a messy affair when I start pouring...

[Harry Robinette]

Lee
I'd seal it with silicon caulk, that should stop the water and the mix from leaking out and will be quick and easy to do.

[Mike Cruz]

Good idea, Harry.

[Lee Alkureishi]

Ok, a little more progress

I wanted to start gently with this puppy, as there were a lot of "firsts" for me in it's making, including the whole welding thing... So, I mounted up a 13" x 3" maple platter blank as the first piece. But, I didn't want to be TOO chicken, so I deliberately mounted it about a 1/2" off centre, just to see how it would handle. Well, here's the results!

The first video shows the lathe in low gear, VFD at 100%, running at top speed of 1300rpm. It's pretty smooth - the only significant vibration was from the motor knocking against the belt cover; it'll need bolted down a little more securely (thanks Mike!).

http://www.youtube.com/watch?v=FCs2-de2Zw0

In the second video, just for curiosity, I wanted to see how the lathe would fare at high speed with the same out-of-balance blank. So, I flipped the belt to the small pulley and hit the switch. There's a delay in coming up to speed, as I had to adjust the belt tension by manually depressing the motor (need to remove a couple of links from the belt). As a result, my hands were both busy so I couldn't show the tach reading - but, it was a little over 2500rpm! Not something I would recommend for roughing this size of blank... The lathe didn't even flinch - minimal vibration, and the legs stayed rooted.

http://www.youtube.com/watch?v=ZY7tUXXMpB4

That's it for now. I'm really pleased with this initial test - it's a lot more stable than I thought. In fact, it's a good deal smoother than my "real" PM90... Now, does anyone have any 34" bowl blanks I can play with?

Lee

[Mike Cruz]

Fantastic, Lee! You did it!!!!!

Looks great. Get that small vibration from the motor settled and you are set!

And who's got 34" blanks? WHO? You have to ask? You might have to drive here, though...