Powermatic 90 bowl lathe - I want biggerer!

[Lee Alkureishi]

Hi all,

So, I was pretty pleased with the old PM90 restoration (http://www.sawmillcreek.org/showthread.php?190195-Restored-Powermatic-90-and-first-bowl-complete!&highlight=), and the addition of riser blocks which brought the wee green beastie up to a 19" swing. After playing with it for a while, though, I kinda sorta wanted something a little bigger, so....

I'm making meself a bowl lathe. Based on a PM90 headstock. It's not quite done, but I'm feeling the need to share it at this stage of development :)

I wanted to make the whole thing from scratch, using scrap/found metal. And, with the exception of a headstock (purchased for a very reasonable price), tailstock (next to nothing on CL) and short bedways (made by Jeff Nicol, bought from Mike Cruz), I think I accomplished that. Well, I guess it's more of a bowl lathe stand, rather than the lathe itself!

The legs are 2" steel fence posts (1/4" thick), welded together with 1/2" thick angle iron and welded to the underside of 1/2" steel plate. Another 1/2" plate is welded to the top of that at the headstock end, and extends behind the lathe for the motor mount. There's a shelf about 8" below the top plate. The headstock riser is made of the same stuff - 1/4" thick steel fence post columns, welded to angle iron top and bottom, and then clad in 1/8" sheet steel. The top half of the legs is clad at the back and sides in 1/8" thick steel siding. The legs are splayed at 25 degrees, and are 24" apart at the bottom. The legs are also 24" tall, and the headstock riser is 14" tall. With the ways in place, the swing over bed will be 34".

Headstock and tailstock are in the mail! Still have to make a riser for the tailstock, but will need to receive it/measure first. The banjo pictured is a prototype, built for my other pm90. Will need to make a new banjo for this little guy too... For the motor, for now it will get the 1hp 3ph motor I took out of my pm90. But, at Arnfest in September I'll be picking up a nice old 3ph 2hp unisaw motor that should work quite nicely... Planning a jackshaft setup to maintain torque at the lower end.

I learned a lot from this build - namely, how to cut and weld metal(!). Probably should have started on something smaller... :) I also learned that metal warps (a lot!) when welding... Nothing a little grinding won't fix, but frustrating anyway!

This new beastie is heavy, even before the headstock, tailstock and ballast are added - no idea how much, but I can barely move/drag it. Can't even get close to lifting it. It's sitting on some levelling feet made from 5/8" bolts and hockey pucks. If the lathe rocks/walks with heavy/unbalanced pieces, I'll probably bolt it to the floor.

I'm no mechanical engineer, but I'm hoping the shape/stance of this lathe will be sufficient for its capacity. If not, it'll be hooked up to a VFD, so I can always turn at 4rpm if need be!

[Lee Alkureishi]

Some pics of the build:

[Lee Alkureishi]

More pics:

[Mike Cruz]

OMG! I'm laughing hysterically, here, dude! I can't believe you. You are TOTALLY nuts. I envy the crap out of you, but you are NUTS.

PM90 green, huh? Didn't want to stray and go "different"?

YES, get a VFD. You'll be SO thankful you did. Of course, that means you'll want to make a remote switchbox with all your controls with magnets so you can place it anywhere. You certainly want to be able to put is somewhere to your right so you don't have to reach across a spinning chunk of wood when something is going wrong to slow it down or turn it off. I can send you pics if you want.

When you get your motor, get a 3 hp if you can. A 34" blank may need it. Especially since you might be roughing that puppy at 250 rpm. That means your VFD will be turned way down, which means robbed power. So, as much as reasonable... I've used a bunch of TECO FM50s and have been happy with them. For my last lathe, I got some kind of EBay for cheaper. It has actually worked quite nicely. But it does have a fan that runs all the time. A little annoying unless you are okay with either unplugging it, or putting in a power switch between the VFD and the wall outlet. I'm thinking of installing one of those...

Lee, it is looking great. It really is. I'm very impressed. I'm waiting to see what you do about the speed control dial. Since you won't be needing it, will you just unscrew the handle and let it just stay on there, or are you going to weld up a plate to screw on? Don't forget to leave that accessible for future access to the spindle.

I'm looking forward to the rest of the build. Trudge on, my friend, trudge on.

[Reed Gray]

You did a good job on the base. I am wondering though if you should reconsider the headstock. Mostly, the P90 isn't made (both shaft and bearings) for the big loads you will be putting on it. Might want to step that up as well.

robo hippy

[Mike Cruz]

Reed, I'm not sure about the bearings, because I'm no expert, but that spindle shaft is quite beefy! Now, I don't know what kind of steel it is made of, and what the parameters of the cast iron in the headstock are. But that thing was built back when they made stuff heavier than they needed to. I guess time will tell...

[Lee Alkureishi]

Thanks for the encouragement :)

Mike - why would I go anything other than my hammered green? I know you did for your behemoth, but I'm a little partial to it, and it'll look nicer next to my pm90 :) The VFD is a definite (in fact, it'll be plugged into the same VFD my pm90 uses), but I'm planning on keeping the speed dial and reeves mechanism too. I've found I use it more than I thought on the pm90 - it's just nice to quickly change the useable speed range for the vfd's pot. As for the remote switchbox, I already have one! It's not quite as fancy as yours, but it does the job nicely on my pm90's tailstock. I'll need a little ingenious positioning of the new lathe to be able to use it easily on both, but it'll do nicely otherwise...

I would love to get a 3hp motor for this, but the unisaw motor came up on BOYD for $40, so I had to jump! Hoping the older design and 3-phasiness will give it enough torque. I'm also thinking about really jackshafting it down to the low speed range, so that'll increase torque too. We'll see! I did put a switch between my VFD and the wall, for the same reason you stated. It's so nice, just being able to flip the switch instead of having to unplug a twistlock every time.

Robo - thanks for the input about the headstock. I hadn't heard that about the pm90 headstock before - I thought that the spindle size was not far off the 3520's? (1 1/8" vs 1 1/4"). The main negative I've read about the pm90 headstock is that the reeves pulley is located a ways behind the outboard bearing (rather than centered between the bearings), which may not be ideal for heavy outboard turnings.

Either way, it's on its way to me now :) I'll give it a go, and feed back on my experiences... If it's no good for the big pieces, I'll still have a second, slightly weird looking, and very sturdy pen lathe :)

Edit: just found out the headstock winging its way to me is pea-green, not hammered green... Ah well, looks like a trip to the paint shop again :)

[Mike Cruz]

Lee, I can understand the green...no worries. Keeping the color scheme will ad a bit of uniformity to the shop, too.

Glad you are going with the VFD. But not sure about sharing. Not saying you can't, but not sure about it. And if you are, you might want to seriously think about a remote switch (one that is truly remote) that you can bring to whatever machine you are using. You do want those controls close and accessible. Not sure how turning one machine on at a time would work with sharing the VFD...other than having some sort of transfer switch. But then certainly only one machine could be used at a time. Granted it is only you there now, but you might (as I've done) end up with a bunch of turning buddies that meet regularly, and it is nice to be able to have multiple lathes going at once.

Agreed on how nice it is to use the speed control. I found that visitors using the PM90 got easily confused, but I was very used to it.

I didn't realize that you had already bought a motor. That makes sense now... As you likely already know, the Unisaw motor is probably a 3450 rpm motor, so you will most certainly need to match up your pulleys to give you a full torque range of 200 (for when roughing out the really really big blanks) to whatever you want your top speed to be. On my lathe, about 1500 is tops. Personally, for a bowl lathe, I don't think you need to go faster than that...but that is up to you.

Best of luck to you with this build, Lee!

[Richard Coers]

I'm not sure I like the position of the legs. Consider how you stand to work on both sides of the bowl. I like the Oneway because the head is so narrow, and when I need to work around the chuck, I tuck in pretty tight to the lathe, near the headstock. Now consider the length of the chuck with a 10" deep bowl on it. That makes the tailstock leg position a consideration. I would have been tempted to keep the legs on the work side more vertical, but keep the back side legs out like you did. Since you made it though, should be easy to change if you need to.

[Lee Alkureishi]

Hi Richard,

Thanks for the feedback, but I don't think the legs will be a problem. I've played with standing all around the base, and they don't seem to get in the way.

I actually based the set of the legs on the dimensions of the robust american beauty (loosely). They're roughly at the same angle, only the bed is shorter. The lower shelf only comes about halfway forward, and I didn't clad the front of the base. Both of these decisions were made to allow me to stand in closer.

Again, I'm no mechanical engineer, but it seems to me that if the front legs were vertical the whole base would be a lot less stable - the riser + headstock assembly will be a full 20" above the top of the legs!

[Mike Cruz]

Of course, only time will tell with whether or not the legs might be in the way, but for stability purposes, I like them splayed, too, Lee. If the fronts were straight down, I would be concerned that an out of balance 30"+ blank might get the lathe rocking. And if the front legs were straight and it was going to topple over, there is only one way it would go...right at you. So, design wise, I say you did right. Now, again, time (and use) will tell whether they are in the way of your turning...though I think you'll be fine.

[Reed Gray]

As some one who always stands at the tailstock end of the lathe to turn bowls, I am used to straddling the legs. They are always a bit in the way, but it is far easier than bending over, or reaching out away from my body. I do hope the lathe was made to your height. One of the things I love about the Robust is the way the legs telescope out from the body and you can adjust the height. Better than my old PM which I had to put up on a 4 X 4.

robo hippy

[Mike Cruz]

Hehe, Reed, my spindle is a little on the high side for some who visit. I've been tempted to make them a "platform". :D

[Lee Alkureishi]

Hi Reed,

Like Mike, my pm90 spindle is a little higher than most as a result of the risers - 46" from the ground. That's a pretty comfortable height for me (i'm 6ft), so I designed the bowl lathe to be the same height. Hopefully should be just as comfortable, though I have read that some like their bowl lathes a bit higher than a single lathe.

Like everything else with this lathe - we'll see!

[Lee Alkureishi]

Got a few goodies in the mail today :)

The speed dial is from my pm90 headstock, which is in a separate package, still to arrive. Looks like the same style as my 1970 beastie.

The tailstock is not a Powermatic - it's actually from a Sebastian metal lathe, but it's easily a match for the pm90 tailstock in heft. #3 Morse taper, but for $25 I can't really complain :) also has about 6"of quill travel, which is kinda nice...

Lastly, the Reeves pulley is a Powermatic but not from a pm90 - it has a 1" bore. Anyone know of a good'n' cheap supplier of arbor bushings?

:)

[Olaf Vogel]

Very nice work there Lee. I applaud your desire to build something rather than buy off the rack by plunking down the ole' Visa card.

I agree that the stance of the legs should be as wide as possible, especially if you're working with wet, raw logs. There's substantial forces you'll deal with at 32" of swing. You might even want to consider a set of horizontal tubes, welding to legs, so you can bolt them to the floor. I've had mine bounce up and down, even though its about 2000 lbs.

3 hp is plenty, IF you can gear down the speed so that your motor is running close to the rated speed.

I like your idea of using a metal lathe tailstock, they are generally very high quality and should work well. That will give you lots of torque. The VFD will be great for speed control. and most importantly, for running large blanks up to speed, SLOWLY. I've had an 80 lbs block fly off the ceiling and far wall, without such a feature.

You asked about bushings? Do you mean bearings? the BigBearingStore.com has a good selection at decent price. i'm assuming you'll use 4 bolt, flat mount bearings and bold a set on each side? I'd go for a large spindle diameter. 1.25 or 1.5 would be awesome.

Looks like a great project!

[Lee Alkureishi]

Hi Olaf,

Thanks for the suggestions. For the headstock, I'll be using a stock pm90 headstock, bearings and spindle. The spindle thread is 1.5" x 8tpi, and the rest of the spindle is bigger - something like 2".

The bushings I was asking about are for the reeves pulley, which has a bore of 1". My motor's shaft is 3/4", and my jackshaft is 5/8". So, I'd need a bushing for the pulley (inside diameter 5/8", outside diameter 1").

On a related note, does anyone see a problem with using a 5/8" shaft for the jackshaft? I'd like to use what I have already, but I'm not sure if the jackshaft would need to be beefier to match the rest of the lathe?

Thanks again,

Lee

[Mike Cruz]

Lee, I'm sure that depends on how long the jack shaft is. I mean, if it is supported in two spots directly on each side of the pulley, I can't see how it wouldn't be strong enough! But I think it all depends on how long of an overhang you have. Your motor has a 3/4" shaft for a reason. I would like to say that you ought to at least match that. You'll have to weigh a bunch of things, mainly total costs: You already have the 5/8" jackshaft. What do you need else? Just the bushing? If you buy a 3/4" jackshaft, you'd still have to buy a bushing. If you buy a 1" jackshaft, you don't have to buy a bushing. How much can you get a 1" jackshaft for? You've seemed fairly thrift thus far...

[Lee Alkureishi]

Hey Mike,

The jackshaft would just be part of the cost - I'd have to factor in new pillow block bearings as well. As it stands, I'd just need a bushing and a large pulley.

Gonna have to play with this -i think I could have the pillow blocks fairly close either side of the big pulley, with the reeves pulley hanging off the back by a small amount.

How much of a pulley reduction do you think I'd need for a 3450rpm motor? The Reeves drive is throwing me off a bit...

Lee

[Mike Cruz]

Well, a two to one would bring your high speed down to 1725. It depends what you want your high speed to be. My thought is that that is plenty fast for a large bowl lathe. But there are plenty of turners that will turn large items at over 2000...just not my thing.

[Lee Alkureishi]

But, doesn't the reeves drive kinda mess that calculation up? Because, at top speed on the reeves drive, the motor-side reeves pulley is much bigger than the spindle-side reeves pulley, which would bring the top speed up again (top speed on my pm90 without a jackshaft was 4000rpm, using a 1725rpm motor). So, I'm wondering if I need to use a much bigger pulley reduction on the jackshaft (say, 1" or 2" pulley on the motor, maybe 8" or bigger on the jackshaft...) to keep the low end speed down. Or, just use a 1:2 or 1:3 reduction and see how the torque is using the reeves for the rest of the speed reduction (and the vfd for the really low end...).

Ah, choices!

Lee

[Mike Cruz]

My PM90 had a 1725 rpm motor. It had a jackshaft. The top speed was somewhere around 2500 rpm (IIRC). I think with simple calculations, you'll be able to figure it out.

Your motor will run at 3450 rpm. If you have a 4" pulley on it, and a 2" pulley on the jackshaft, the jackshaft will spin at 1725 rpm. Now, you need to do the math on the next two pulleys. So, if in the fastest position, your lower Reeves drive pulley is at 4" and your upper Reeves drive pulley is at 2", you'll have a top speed of 3450. And if in the slowest position, your lower Reeves drive pulley is at 2" and your upper Reeves drive pulley is at 4", then you'll have a slowest speed of 867 rpm...with the Reeves drive control. Bottom line is what do you want your highest speed to be? In this scenario, you can go from 867-3450 with full torque. As you start to use your pot to slow down the rpms, you also lose hp and torque.

So, if you instead went from an 8" on the motor and a 2" pulley on the jackshaft, you'd have a range of 1/2 of the above and have a range of 433-1725 rpm. BUT, BUT, BUT...this is all based on the numbers I just gave you for the Reeves drive pulleys and those were pulled out of my butt. I don't know what they are. Again, you'll have to do the math.

And also, you may not have to be so drastic with the pulleys sizes from the motor to the jackshaft if the numbers from the Reeves drive will put you where you want to be.

Hope that was helpful, and not confusing.

[Lee Alkureishi]

Mike, thanks for the info. I think the "big" end of the reeves is 6" and the small end is 2". Will need to wait until I'm back home later in the week to measure for sure. That being the case, I think I can go with my currently available step pulleys on the motor and jackshaft (2-3-4-5, 5-4-3-2). At the lowest end, that'll give a 2:5 speed reduction at the jackshaft, bringing the motor's 3450rpm down to 1380rpm. Then, the lowest end on the reeves pulley should give a 1:3 speed reduction for a low speed of 460rpm - without the VFD. That should allow me to keep the VFD at or above 50% for the most part. From my experience with the pm90, the motor's oomph (hp, torque, or whatever it is...) drops off significantly at about 30% or so. We'll see how it works with the bigger pieces... If it's not cutting it at 50% (30Hz), then I'll swap out the jackshaft's pulley for a bigger bugger to drop the absolute rpm more.

Then again, my reeves pulley sizes are just from memory (or my butt, as you put it...) - if the small end is less than 2", all the better :)

Lee

[Mike Cruz]

If your memory serves you correctly, the math works out, and you ought to be just fine. Just remember that all you need is for the slowest speed to have full torque at around 400 rpm and you ought to be fine. From there, you'll be able to use your Reeves drive to get up to 1200 rpm without changing the belt. And honestly, if you are turning big bowls on it (18" and bigger), you probably won't ever need to change that belt from that position (in my opinion).

[Olaf Vogel]

Lee,

5/8's is a little small for a long shaft, but if the pulley cones fit tight on the shaft, that will prevent flex as well. (assuming the cones take up most of the unsupported length which they should.)
A lot of the time more powerful motors have larger shafts, not to prevent flex, but rather to provide a larger diameter for transmitting torque.

I've made my own counter shaft pulleys before:
- laminate up multiple layers of birch ply (other material works too)
- drill a hole through the layers and pound in the shaft, nice and tight.
- I used split taper bushing like this http://www.princessauto.com/pal/Split-Taper/1-2-in-Bore-Split-Tapered-Bushing/8069494.p to provide torque transfer.
- Bolt on the wood and then turn it. I cut in v-groves for the belts: took an old chisel and ground it to the shape/depth of the v-grove

Cheap and easy, and you have an infinite speed selections. Normally you duplicate your main shaft, so your belt length is constant.
But that's not a limiting factor if your countershaft has lot of room to move.
For a large bowl lathe, I'd want a large (mechanical speed range) AND a VFD. :)

Olaf

[Lee Alkureishi]

Just a quick update on the build... Slowly progressing - dang job keeps getting in the way!

I received my headstock a couple of weeks ago. It was a rusty mess, but actually in great condition otherwise. It's the same style as my other pm90, so I'm guessing it's from the 70s. Pea green paint, though - egh! I tore it down, derusted and repainted. Just waiting for my new bearings before puting it all back together :)

I also took the Sebastian lathe tailstock apart, stripped the paint and rust, and painted it to match. Nobody will ever know it's not a powermatic! Now I just have to figure out the riser for the tailstock... that's going to be fun... If anyone has any suggestions, I'd love to hear them. It'll need to be 11" tall, and at least 7" wide. The ways are 10" across, so I'm toying with the idea of a wider base, making the riser trapezoidal rather than square. But, that does complicate the design considerably! Pondering...

This weekend, I finished building my new banjo. I think it's an improvement on my other design - it's modelled roughly on a pm3520 banjo, with dimensions to suit the 34" swing of my beastie. It's 19" long, and stands 15" tall. It's heavy, but not quite as heavy as my previous design, which was made solely from angle iron. This one is mostly from pipe, with some angle for the base. I'll see how it is in use - if I'm getting much vibration, I'm thinking of pouring concrete in from the bottom of the vertical section. Isn't it purdy?

Lastly, I had a nice breakthrough on the motor situation last weekend... Rooting around the local scrappie, I happened upon a very nice Baldor 3ph 1870rpm motor. It's still a 2hp, but everything else about it is perfect - inverter duty, and "explosion proof"! Tested and runs nicely. Bearings are in the mail. Looked it up online, and it retails for $900-$1500. Not bad, for the $12 I paid for it!

Last few things left to do:
1) Put the headstock back together
2) Level the headstock riser
3) Build a tailstock riser
4) Install the tailstock and line everything up
5) Mount the motor and jackshaft
6) Turn!

Hope someone finds this stuff as interesting as I do!

Lee

[Mike Cruz]

You're doing a great job, Lee. Thanks for the updates. And I'm waiting on baited breath to see how it turns!

[Lee Alkureishi]

Thanks Mike :)

When I temporarily installed the headstock (before the restore), it now looks like a mighty tall and narrow structure... Hopefully the 2 foot wide stance is enough to keep it stable, and I THINK I welded on enough iron and steel to prevent the base from racking - we'll see!

[Mike Cruz]

Lee, if you need to, you can always weld on cross braces and diagonals...if you need to. Also, You could weld extra "legs" to the outsides of the existing legs with a wider "stance". The beauty of your design and doing this yourself...you can always add or modify without worrying about messing up a "brand name" lathe. Keep at it!

[Dick Strauss]

Lee,
The reeves drives are made for a set amount of hp. So, if you increase the hp on the belts, the belt may pull hard enough so that the spring (forcing the two halves of the reeves together) cannot keep the reeves halves at a set spacing. In the situation where you are taking a heavy cut or you are turning a large diameter piece where lots of torque is needed, you may reach the point where the belt slips using a 2hp motor instead of the stock 3/4-1hp version.

Jack shaft systems usually consist of three pulley groupings with one pulley on the motor, one or two pulleys on the jackshaft, and one pulley on the spindle. I would suggest stepped pulleys for versatility purposes at all three positions. Avoid the cheap Chicago cast zinc/al pulleys. I would suggest Maska or Browning cast iron pulleys. Here is a link to the cheapest source of good pulleys I've found (take out the space)... http:// www.electricmotorsite.com/mm5/merchant.mvc?Screen=CTGY&Store_Code=EMS&Category_Code=pul_step_a (http://%20www.electricmotorsite.com/mm5/merchant.mvc?Screen=CTGY&Store_Code=EMS&Category_Code=pul_step_a) . You can also check ebay but it is hard to find the right quality, step sizes, number of steps, and bores all in one item. Grizzly is a good source for single cast iron pulleys but didn't have step pulleys the last time I checked their site.

I have no relationship and have never done business with Electric Motor Site so do so at your own risk but I would probably give them a try.

I wish you well! I can tell how excited you are about the turning possibilities after the modification/creation is complete.

[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...;)

[Roy Wall]

Lee,

Just saw your thread and tremendous CONGRATS! The lathe looks and runs great. Heavy duty built at a fraction of retail cost - love it! Now that you've conquered PM90 clone, I say go for the Oneway version. Excellent!

[Mike Cruz]

Yeah, Roy, good idea...in concept. But finding a Oneway or Robust headstock for anything that wouldn't break the bank would be near impossible.

[Harry Robinette]

Lee
That's outstanding so glad to see it run and with minimal vibration, I think you got a WINNER there. Congrates.

[Lee Alkureishi]

Thanks for all the positive comments :)

I really enjoyed this build. I learned a lot too, and developed a few new skills in the process. I'm looking forward to turning on it even more!

I'm hoping to make another at some point - may take some of the design features from the other big lathes - but, as with everything - it's all on hold for the foreseeable future!

Lee