repair or replacing motor on old Rockwell Delta lathe

[mark ahlenius]

A few questions about my old lathe for the experts here: I have a vintage Rockwell Delta lathe which I believe was made back in the 1950 era - I do not know the model number but have attached pictures of the lathe and the motor. I have not used the lathe for about 6-8 months. Today when I tried to use it there was a loud screeching noise which I isolated to motor. I took off the motor and ran it separately and that is for sure where the noise is from. It sounds like bad bearings to me. The shaft spins ok but after running for 20+ seconds it starts to make this screeching sound. Nothing seems loose on the motor chasis. The motor is an original Rockwell motor (see pix). Its a 1/2 HP, 120VAC, 1725 RPM single phase motor, with a 5-step pulley. Is what is best to try to find a replacement or to have it rebuilt? There is a Dresilker Motor repair facility in the next town over where I could take it later next week. Question 1). Wondering what the wood turner's wisdom is for this older unit. It seems like a good lathe, and I am a very basic amatuer turner. Would you recommend getting the old motor repaired or just buying a new one. Question 2). If I should purchase a new motor, recommendations on where to get one and what kind so it would not be effected from all the dust and shavings? Question 3). There was no real way to tension the belt on this when I got the unit. So to change the belt to another pulley pair, I had to loosen the motor from the bottom plank enough to lift the motor up and release tension on the belt and then move it to another pair of pulleys. There must be a better way. Is it recommended to put the motor on a hinge-plate with some sort of spring tensioner to make speed adjustments easier? thanks very much for your assistance. Looking forward to learning more on this forum. best, 'mark

[Bill Dufour]

Probably just need to replace bearings. Is it ball bearing or sleeve bearings? Lokks easy to repalce those bearings. Get sealed not shielded bearings from the bay. I would use a TEFC motor. I would get one that is same rpm, double the horsepower, but three phase. You can buy a VFD that can take single phase 120 (rare) or 240 and make three phase. Turn the knob and the motor speed will change. Also gives you reverse which is probably not a good thing on a woodlathe. I recommend the extra HP because at lower speeds it will lose HP.
make sure to get the same size output shaft as the pulley and not too hard a change. A lot of older machines have a hinged motor plate and let gravity tension the belt.
Bill D.

[Carroll Courtney]

Welcome Mark,good questions.If your handy you can make those repairs for about 10-12.00,bearing can me had fairly cheap unless you go with one of the top of the line bearing names.But for us guys that play around the cheap ones are good enough.I would think if you had the repairs done,the cost would be just about around the cost of a new motor from Tractor Supply.Going with a new motor gives you more choices such as getting your self TEFC motor which is Totally Enclosed Fan Cool motor which means no more dust to deal with and you could increase the hp if needed.Your right about the belt,I had that lathe at one time had those same issues.If you can do some research looking at Delta band saw manuals of that same vintage as your lathe you will find how belt tension was handle in a band saw which could be done the same on your lathe.If you could find yourself a butt hinge thats kinda on the heavy duty side,half hinge bolted down and the other half with a 1/8 plate bolted or weld to the other half of the hinge that would have the motor mounted on it.Look at some manuals would give better ideals than what I am trying to explain.Those cast iron legs adds alot of value to that lathe.Good luck and lets us know about your repairs-----Carroll

[Jim Barkelew]

+1 on what Bill said if you want to keep the lathe. I looked at the cost of doing it right for my newer version and I was getting up to the cost of a new midi lathe. My tail stock is junk so replacing that and a motor/VFD was not worth it. I just bought a 1HP motor and suffer with the tail stock.

Replacing the bearings is relatively easy but opening up the motor can ruin it if the nuts are frozen and the bolts break.

[mark ahlenius]

Hi

first - thank you for everyone who responded to my questions. All very educational and helpful for me.

Nevermind my pre-edited post, I was able to get the pulley off by heating it with a heat gun and rubber mallet.

Now I just need to try to find a 1 to 1.5 HP motor with a shaft which is at least 2.5" long and 3/4" in diameter.

best

'mark

[Ed Aumiller]

I have an old Powermatic, very similiar to that.. I did what Bill said and it is GREAT..

Highly recommend putting a used 3 phase motor on it with a vfd.. cost should be less than 150-200.

You will then have a true variable speed on a rock solid lathe frame...

The ability to adjust speed so easily makes it equal to or better than some of the newer lathes..
It will make your turning much more enjoyable...

[mark ahlenius]

I have an old Powermatic, very similiar to that.. I did what Bill said and it is GREAT..

Highly recommend putting a used 3 phase motor on it with a vfd.. cost should be less than 150-200.

You will then have a true variable speed on a rock solid lathe frame...

The ability to adjust speed so easily makes it equal to or better than some of the newer lathes..
It will make your turning much more enjoyable...


Hi

where did you find the motor and VFD? The shaft of the current motor with its 5-step pulley is 3/4". That's not something very common from looking at the Tractor sales store nor Grainger.

thanks!

'mark

[Olaf Vogel]

First, try soaking your bearings with WD40 or silicone. Chances are, the lubircant just dried out.

Small motors like this are typically not worth rebuilding, but as others have said, swapping bearings is easy - with a bearing puller.
This is a very standard motor.

If you want speed control:
Look on Craigslist or other used suppliers.
3 PH motors are really cheap, like ~$50. 1 hp should be enough for that lathe.

A new pulley is also easily available so don't bother looking for a 3/4" shaft.
And McMaMaster has EVERYTHING :) https://www.mcmaster.com/#step-pulleys/=1axs7ve

Delta VFDs are available on eBay, used, very cheap. I recently priced a 1 hp at $75, incl shipping, from China.
I personally really like the Delta ones because they have a READABLE manual.

[Jim Barkelew]

I have a single pulley on my motor a built a sliding motor mount to align it with the step pulley on the spindle. Not great but usable for a 40 year old lathe I bought new.

[mark ahlenius]

Thanks Olaf,

I was able to pull off the old pulley by soaking it with white lithium grease and I also soaked the 4 long bolts which hold the motor frame together with the same. I then heated up each of them with a heat gun and they each came off without damage. I'll see what the bearings look like when I pull the chasis apart today. If I can get/replace the bearings for cheap, then its a no brainer, otherwise I'll try to find the 3 phase 1 HP (or 1.5 HP) TEFC motor with a VFD.

Appreciate all the help everyone!

Happy New Year to you all.

'mark

[Dennis Ford]

Check the fan, sometimes they get damaged or loose on the shaft and make loud noises.

[mark ahlenius]

Thanks Dennis,
opened up this little puppy and I think its just time to say goodbye to this Delta Milwaukee motor. Inside the frame housing the wiring appears to be shot, a number of bare spots in the insulation of the wires coming from the connection block. They have the insides packed with fiberglass insulation - most likely to keep the dust out of the rest of the frame.
best
'mark

[mark ahlenius]

<p>
Bill and rest, since I am new to VFD&#39;s - should I only be looking for &quot;inverter-rated&quot; 3-phase motors? Searching around eBay this afternoon, but don&#39;t want to order something which is not going to work. Also been reading up a little on the kinds of VFD units. If any of you have done this (Bill, Jim or others) could you share a little more detail on the kind of motor and VFD model you used? Anything to be aware of as far as brands or specifics? I can easily add a new 220 volt outlet for a VFD unit, if I cannot find 120 VAC unit. thanks again everyone, this help has been great! &#39;mark</p>
<p>
&nbsp;</p>
<p>
p.s. &nbsp;- I attached a pix of my motor&#39;s internal wiring to its terminal block, as can be see the wiring is a bit toasted.</p>

[Olaf Vogel]

I have no idea why insulation would be inside.

eBay is not a good source for motors, typically. Their value is too low to be worth shipping.
And you should be able to source them locally.
3 ph, 208v are typically industrial cast offs - hence cheap.

https://www.ebay.com/itm/ORIGINAL-Delta-Inverter-VFD-004S21A-VFD004S21A-220V-1-Phase-J875/182860721726?hash=item2a93592e3e:g:NSoAAOSwv0tVWs3 d
is an example of a VFD that will work, but almost all will need 220v input.

Look here for the model you want: https://www.deltaacdrives.com/delta-vfd004s21a/
Then search for that model.

I have 5 of these VFDs up to 7.5 kw, none have let me down.

[Bill Dufour]

I would say any fairly modern 3 phase motor can handle a VFD drive. If it is painted any color other then factory black it is probably new enough to have good insulation.
3 phase motors tend to be made to industrial standards so they are not cheapy home owner adequate insides. Plus a three phase motor has no starter switch or capacitors to go bad.
If you are buying a used motor check all three power leads to ground for infinite resistance. then check each pair. Each pair should have the same low resistance. Probably less the 5 ohms.
On my drill press I installed a VFD and have not moved the belts in ten years. If you want you can use the factory switches as low voltage control switches or install new switches where you like.
Bill D

On Ebay many sellers do not list the shaft diameter or key slot size. Most will respond to questions so you have to ask. I like to ask with suggested sizes but a spread like is this 1/2, 5/8 or 3/4 diameter. If I just ask is it 5/8 I figure they may be lazy and just say yes without measuring.

[mark ahlenius]

Its hard to tell if a motor like this one would be "inverter-ready" -

https://www.ebay.com/itm/MARATHON-1-HP-1800-RPM-TEFC-230-460-VOLTS-143JM-WASHDOWN-3-PHASE-MOTOR-N201/362116060393?epid=2271540368&hash=item544fcc94e9:g:QWIAAOSwHIlZzUU9

Was hoping to find something a little more powerful due to the lower torque on lower speeds when using a VFD.

thoughts on a motor like above?

thank you

'mark

[Jim Barkelew]

I bought my VFD for my home-built lathe from Automation Direct. It was easy to set the parameters for the motor. Good documentation. I used a Dayton motor that is about 50 years old and came off my bandsaw. To help with low speed torque I used a small pulley on the motor. Wood lathes are generally intermittent low power use so overheating should not be a problem.

[Curt Harms]

<p>
Bill and rest, since I am new to VFD's - should I only be looking for "inverter-rated" 3-phase motors? Searching around eBay this afternoon, but don't want to order something which is not going to work. Also been reading up a little on the kinds of VFD units. If any of you have done this (Bill, Jim or others) could you share a little more detail on the kind of motor and VFD model you used? Anything to be aware of as far as brands or specifics? I can easily add a new 220 volt outlet for a VFD unit, if I cannot find 120 VAC unit. thanks again everyone, this help has been great! 'mark

I would recommend taking a look at Dealer's Electric for VFDs and 3 phase motors. I just bought a VFD & 1/2 h.p. motor from them for a drill press. I went with an open box VFD & new surplus motor. I went with a 230 volt VFD but Dealer's Electric has several 115 volt VFDs available. Their prices seem competitive and they're sorta local to me. They also offer motors with synchronous speeds of 1200 r.p.m. Using one of those should help with the higher torque at low r.p.m. when using a VFD. Running an 1800 r.p.m. motor at 30 Hz. would yield a motor speed of 900 r.p.m. Running a 1200 r.p.m. motor at 30 Hz. would yield 600 r.p.m. if my understanding and math are correct.

http://dealerselectric.com/115V-single-phase-input.asp

[mark ahlenius]

So I think I'm going down the 230 VAC - 3 ph motor with VFD route. Looking at motors running 1800 RPM which was similar to my old Delta motor at 1725 RPM.

Would it make sense with the VFD to use a 1.5:1 or 2:1 pulley ratio (motor to headstock) so that my highest speed on the lathe at full motor speed on the VFD is 2700 or 3600? I'd normally run my lathe at a lower speed but try to not sacrifice the torque?

I'm assuming that the VFD drive does not spin the motor faster than its nominal RPM and if it does, I was not planning on running the motor faster than what it was designed for. I hope this makes sense.

thanks

[Geoff Crimmins]

You should go over to owwm.org, join the forums, and offer the Delta motor for sale in the classifieds. Someone there would probably like to buy it, fix it, and put it to use. Most lathes that use a VFD have pullies with at least two steps, one for slower speeds and more torque, the other for higher speeds with less torque. Just keep the 4-step pullies that came with the lathe. A VFD can run a motor faster than its nominal RPM, but you're correct that it's not a good idea to do so.

--Geoff

[mark ahlenius]

Great idea. Thanks very much Geoff.

'mark

[Olaf Vogel]

So I think I'm going down the 230 VAC - 3 ph motor with VFD route. Looking at motors running 1800 RPM which was similar to my old Delta motor at 1725 RPM.

Would it make sense with the VFD to use a 1.5:1 or 2:1 pulley ratio (motor to headstock) so that my highest speed on the lathe at full motor speed on the VFD is 2700 or 3600? I'd normally run my lathe at a lower speed but try to not sacrifice the torque?

I'm assuming that the VFD drive does not spin the motor faster than its nominal RPM and if it does, I was not planning on running the motor faster than what it was designed for. I hope this makes sense.

thanks

Assuming you do bowls.....

If you are going 3 PH, then set up your gearing for the lower speeds.
You can use the VFD to raise the hertz above 60 and generate the higher speeds. So a 1800 rpm motor can run at 3600, when the VFD provides 120 Hz.
Yes, 3PH motors will do that. Its just that no utility company delivers electricity at 120 hz...

And you will get better torque at low speeds

How do I know? I have have an 8 pole motor, that runs at 880 rpm, so I get the torgue.
If I want higher speeds, I use my VFD to run at 120 Hz.
:)

[mark ahlenius]

<p>
Hey everyone. Thanks for your help and advice on this project of mine. I purchased a Marathon 1 HP 200 VAC (not a typo) 3 phase motor from Dealer&#39;s Industrial Equipment along with a Teco VFD. THey came as a package (preprogrammed as well) deal which is what I could afford right now. I still need to order a step pulley with a 7/8&quot; bore which does not seem that common. My question is that i want to make a hinge plate type belt tensioner for this motor so I can still adjust between the pulley steps easily. Since I don&#39;t have access to a welder, I was thinking of making it from 2 pieces 3/4 high density baltic birch plywood and use a couple of heavy duty hinges I picked up. The motor hinges I see online are metal for the most part but not seeing any for sale. I may cover the motor side of one of the pieces of wood with ~12 ga steel from an electrical box cover. &nbsp;I could also make the wood plates which extend the hinge out of hard maple. &nbsp; Wondering your thoughts on this approach. &#39;mark</p>

[Olaf Vogel]

I've used door hinges without issues. Its a fairly light motor
Baltic birch works well. Did that on a 5 hp motor.

The hinge idea is good, you just need to figure out the pivot point, so that you get the right amount of tension.
2 options I know:
- spreadsheets and some trigonometry, or
- trial and error - I'd use cheap plywood for this route.
:)

The problem with this is that under load, the motor tends to come up and reduce tension. That can be a good thing, if have a catch.
But its really hard to tune.

The other option is a sliding motor mount. With horizontal tension applied by toggle clamps (https://www.homedepot.com/p/BESSEY-450-lb-Auto-Adjusting-Toggle-Clamp-and-Horizontal-Handle-with-Vertical-Flanged-Base-STC-IHA15/206473989)
I like this solution because its really easy to set accurately.

[mark ahlenius]

<p>
ok I was planning on using a couple of springs to apply additional tension on the motor pulling it downwards. Right on the trig for the distance to select for the motor on the hypotenuse of the movable tension arm. Have you or anyone else found a good source for step pulleys with a 7/8 inch bore?</p>
<p>
best &#39;mark</p>

[Curt Harms]

<p>
ok I was planning on using a couple of springs to apply additional tension on the motor pulling it downwards. Right on the trig for the distance to select for the motor on the hypotenuse of the movable tension arm. Have you or anyone else found a good source for step pulleys with a 7/8 inch bore?</p>
best 'mark

Here's a source, don't know how good it is.

http://www.wttool.com/index/page/product/product_id/12140/category_id/15990/product_name/V-Groove+Step+Pulleys

[Perry Hilbert Jr]

nearly every machine in dad's shop that had multiple speed pulleys had a motor mounted on a board and the board on hinges. I did the same for a cement mixer I bought for $15.00. The hotor was on a pice of pywood hanging under the hopper. Only instead of hinges, I just used electric fence wire to wire one end to the frame. It worked fine like that through several "projects" over a span of 12 years. Just don't leave it out in the weather.

Almost every farmer I know, has a box or bin somewhere with spare electric motors for various pieces of equipment. Corn grinders, hay elevators, etc. I am getting low, there are only three out there right now. a half, a 3/4 and a fill hp.

[David L Morse]

ok I was planning on using a couple of springs to apply additional tension on the motor pulling it downwards...

I used a bungee cord for that purpose on a saw I once had. My daughter would always tell me that I should add some duct tape to complete the look.

[mark ahlenius]

or you could probably use duct tape in a pinch for a v-belt.

;-}

[Don Bunce]

I bought that same VFD/motor combo a few months ago for my South Bend lathe. A good source for 7/8" bore pulleys is Amazon.com

[Jim H Bennett]

I have never posted on sawmillcreek, or any other site before (Hope I am doing this post correctly). But I do check here before I make any purchasing or repairing decisions. Thanks to all for all the help I have gotten over the years. I had a similar (almost identical) motor rebuilt recently, new bearings, new capacitor, all new lead wires inside case, cost was $180 and it runs perfect. Patchen Electric in Lawrence KS did the work. They told me this motor will run another 40 years. The motor is from a vintage 1260 Delta lathe I am in the process of restoring. As a side note, I am looking for the four step pulley for the headstock for this lathe. The shaft diameter is 1-1/4 inches. This pulley is hard to find. Delta has this pulley as new old stock, but they want $350 for it. Again, thanks for all you guys for your expertise and advise.

[mark ahlenius]

All,
its been a while since I posted on this project. Per suggestions from this discussion group, I ordered a new 3-phase motor and VFD Dealers Industrial equipment in NY. I was excited when it came back in Jan but then I broke my arm and have been out of commission for a long spell.

Just working on it again now. I've built an adjustable platform so i could adjust the belt tension for the various step-pulley sizes. (see pix) After testing this I realized that the bearings in the headstock were not in good condition. Seems that these are semi-standard bearings from the ~1953 vintage lathe - ND C88505 and I see them available at a few auto parts stores in the area.

My question is about removal. When I opened the outer dust cap - as you face the lathe with the headstock on the left, this would be the leftmost end, the entire bearing was rotating in the machined headstock. This of course means that the bearings are shot but is there anything else I need to do when I replace it to stop the entire bearing from spinning again?

Would anyone know the best way to remove the bearings - do I need a puller for this? Also any pointers for reinstallation would be helpful.
If there's a little longitudinal play in the shaft, should I try to add some shims?

thank you

'mark

381252381250381253

[mark ahlenius]

Hi Jim,

my headstock pulley was in pretty good shape, I just had to carefully straighten a few of the pulley flanges, but now it seems ok. I did have to get a new motor step pulley as my new motor has a 7/8" bore. I found mine on Ebay, for about $40. Gradually I am rebuilding this old beast. i think my Delta lathe is ~1953 vintage based on the serial number. I hope you have been able to find a new pulley. I was told my local motor repair shop would not even touch that old small motor so i just opted for a new one and really like the variable speed drive. learning a lot with this project and hopefully it will all work out.

best

'mark

[Leo Van Der Loo]

All,
its been a while since I posted on this project. Per suggestions from this discussion group, I ordered a new 3-phase motor and VFD Dealers Industrial equipment in NY. I was excited when it came back in Jan but then I broke my arm and have been out of commission for a long spell.

Just working on it again now. I've built an adjustable platform so i could adjust the belt tension for the various step-pulley sizes. (see pix) After testing this I realized that the bearings in the headstock were not in good condition. Seems that these are semi-standard bearings from the ~1953 vintage lathe - ND C88505 and I see them available at a few auto parts stores in the area.

My question is about removal. When I opened the outer dust cap - as you face the lathe with the headstock on the left, this would be the leftmost end, the entire bearing was rotating in the machined headstock. This of course means that the bearings are shot but is there anything else I need to do when I replace it to stop the entire bearing from spinning again?

Would anyone know the best way to remove the bearings - do I need a puller for this? Also any pointers for reinstallation would be helpful.
If there's a little longitudinal play in the shaft, should I try to add some shims?

thank you

'mark

381252381250381253

Got this for you Mark, if you still need it.

381332 381333

[mark ahlenius]

Leo,

thanks very much for your posting. Very helpful.

Have a great day!

'mark