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Rebuild/refurb Powermatic 3520b

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Forum topic by TedSherman posted 10-17-2017 10:12 PM 739 views 0 times favorited 13 replies Add to Favorites Watch
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TedSherman

18 posts in 1000 days


10-17-2017 10:12 PM

Topic tags/keywords: powermatic 3520b powermatic 3520b inverter powermatic 3520b motor powermatic 3520b rebuilding

I just got earlier today a Powermatic 3520b, but without the motor and all electronics (switches, cables, control panels, etc), for $400. It’s got the headstock, bed, tailstock. The spindle turns smoothly and the pulleys look good. The electronics were damaged/destroyed from a fire in the other side of the guy’s shop. yea, I know, I could have been suckered, but anyway.

I couldn’t find a discussion here regarding rebuilding a Powermatic, but if there is one could someone point me to it. If not, do any of you have recommendations for non-manufacturer parts and/or where I can get them? Or do any of you have 3520b parts that you’re willing to sell? This’ll probably be a long process. I’m okay with electrical, but no genius at it. I much prefer wood! I talked to Powermatic this morning and the tech guy there thought I could probably replace all the “innards” (my term) for $1200-1500. Part of me says go all original manufacturer parts, but the other part says save $. Also, I’ve heard/read problems about the OEM Delta inverter—that it trips and/or fries rather easily.

I’m open to any/all advice and suggestions. Feel free to contact me privately tedsherman@me.com.

Thanks,

ted

-- Ted


13 replies so far

View Loren's profile

Loren

9633 posts in 3486 days


#1 posted 10-17-2017 10:21 PM

Sign up at http://owwm.org

There’s a buy/sell board there for old machines.

View TedSherman's profile

TedSherman

18 posts in 1000 days


#2 posted 10-17-2017 10:36 PM

Thanks, but this one’s only 2 years old.

-- Ted

View Nubsnstubs's profile

Nubsnstubs

1207 posts in 1569 days


#3 posted 10-17-2017 10:54 PM



Sign up at http://owwm.org

There s a buy/sell board there for old machines.

- Loren


It’s not an old lathe. Doubt it’s 10 years old…..

I got a 3520A a couple years ago. To get it home, I put the headstock, tailstock, and banjo on a platform behind the seats I made for my truck years ago. When I got home, the headstock decided it wanted to roll, and when it did, the VFD face ended up hitting the banjo. Put a crease on the keypad.
I figured it would not work, but to my surprise, it came on and I turned a few small 8” od pieces. When I decided I was ready for the big stuff, over 18”, to check progress, I would shut it off, but it would trip and freewheel to a stop. Aggravating to say the least, and I would reach around to the face of the VFD, and try to reset it. I’m guessing I must have changed the programming because it stopped working after 2 weeks.
Since I already had a 3hp VFD connected to power for my 12” lathe, I just disconnected the PM electronics, and connected the Hitachi VFD to the PM motor. It worked fine, but I still get trips from larger stuff. The PM motor sends a signal to the VFD when I shut it down, and that releases the brake that does work on the smaller stuff. I have learned to live with it.

Hopefully the motor bracket is still on the lathe. If so, just measure the distance between holes, and find yourself an end mount motor that fits the hole pattern. Get a VFD from a number of sources. I got the Hatachi from Drives Warehouse in 2010. It’s a 3 HP 220V 10 amp unit that puts out 3 phase power. I have never had an issue with it until I connected it to the PM motor and get the trips when turning larger stuff.

It sounds like you probably don’t have a belt either. If that’s the case, when you remove the spindle to replace it, check the seals on the bearings, and replace them if you see any burn on the seals. ............. Jerry (in Tucson)

-- Jerry (in Tucson) www.woodturnerstools.com

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TedSherman

18 posts in 1000 days


#4 posted 10-17-2017 11:28 PM

Thanks, Jerry. No, the motor bracket isn’t still there. Oddly, there is a belt. The spindle turns very smoothly.

-- Ted

View Nubsnstubs's profile

Nubsnstubs

1207 posts in 1569 days


#5 posted 10-18-2017 02:34 PM

Ted, track down the guy you bought the lathe from, and find out where the motor went to. You just might save a bunch of money if it’s not too late.

As far as the belt not being burnt, that’s good.

On my lathe, I can see the outside rubber seals on both bearings, so a closer inspection might be in order.

I would think even if the guy was asking $1000 for it, it would still be a decent buy, but at $400, that should be considered robbery. Cast iron doesn’t burn, and I don’t think it warps to any degree, so just the metal is worth much more than you paid. That’s my opinion.

A VFD can be gotten for under $300, a 2 hp 3ph 3450 motor can be had for about 3-400 from Graingers, the switch both forward/reverse, pot, and emergency switch can be gotten for under $200. You’re looking at $900 to get this up and running. I didn’t include the tach as you really don’t need one, but that can be upwards of a couple hundred bucks.

In case you’re wondering, the belt is a J9×26” long.

............... Jerry (in Tucson)

-- Jerry (in Tucson) www.woodturnerstools.com

View JoeK1's profile

JoeK1

6 posts in 253 days


#6 posted 10-18-2017 10:36 PM

The motor is special and has an extended output shaft of over 6” in length. Don’t think you will have any luck finding a replacement other than Powermatic. The Inverter frequency output is 140 HZ at full speed, higher than what is usually recommended for standard or inverter rated motors. Is the original motor still serviceable?

View TedSherman's profile

TedSherman

18 posts in 1000 days


#7 posted 10-19-2017 12:39 AM

No, I can’t get the motor from the guy—he no longer has it. Just the bed, new, is over $1000 and the legs are over $500. I’ve got another guy with a new motor (in the packaging) and some other parts willing to part with it for $500, so I’ll probably do that. I’m a bit leery about having to program a non-PM inverter, but others say it’s very doable. It’d save over $300.

-- Ted

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TedSherman

18 posts in 1000 days


#8 posted 10-20-2017 09:08 PM

Jerry, can a motor with the right length shaft be gotten from Grainger’s?

-- Ted

View Nubsnstubs's profile

Nubsnstubs

1207 posts in 1569 days


#9 posted 10-20-2017 10:17 PM

Ted, I just went to Graingers, and they do have some, but cost more than the 500 your guy will accept. If it’s a PM motor, you can’t go wrong. Hopefully some of those extra goodies is the mounting bracket.

You said the pulleys look good. You actually have both???

I just measured the PM motor. From back of the motor to the end of the motor pulley is 15 3/8-1/2”. It’s probably closer to 15 3/8”. The motor bracket is made from 3/8” steel and has the belt adjustment slot. They are real easy to make if you had to.

My Hitachi VFD was programmed for a Dayton Motor from a Dayton Dust collector I had when my business was active. When I needed a 3 ph 2 hp motor for my lathe, I took the DC apart, and had the VFD programmed for it.

When the PM VFD stopped working almost 2 years ago, all I did was disconnect the PM VFD from the motor, and connected my Hitachi VFD to the PM motor. There was no programming to do as it was done for the other motor. I’m still using it today, and the only problem is it “ERROR” code’s when I shut it down to look at progress. I believe that signal comes from the motor and has nothing to do with the VFD. It did the same thing on the PM VFD also when it did work for me.

When you do find a VFD, don’t try to mount it into the existing holes. That is the dumbest thing PM did on that lathe was to mount the VFD facing a way from the operator. Get your self a piece of 1/4” x 5 1/2+x 15 1/2+ Aluminum plate and match up the existing holes on the headstock to the bottom portion of the plate. Mark new holes for the new VFD, and mount it facing the operator instead of away. It will be above the headstock and take up some of the flat space that’s there, but it’s better than not being able to see if you have an “ERROR” code. I can get you a picture of that what I did if you need to see it.

On this lathe, the PM, I’ve decided I wouldn’t drill any holes into the frame for mounting things, but instead am using existing holes. It’s a challenge to say the least, but I’m making progress. I’ll get some pictures after my next bit if ingenious engineering. It’s going to be over a month before I can complete it, but before Thanksgiving. ....... Jerry (in Tucson)

-- Jerry (in Tucson) www.woodturnerstools.com

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TedSherman

18 posts in 1000 days


#10 posted 10-22-2017 04:34 PM

Jerry, I’ve got the spindle sheave (what the PM manual calls the upper pulley, #63 on the parts diagram), but not the motor sheave (the lower pulley, #28 on the parts diagram). I’ve been trying to remove the quill/lead screw because they appear to be frozen. I followed the advice on the Doc Green website (using a block of wood against the rear of the lead screw and hitting the wood with a hammer), but it’s just not moving at all. Any suggestions ? The Doc Green website has great info on the VFD and how to program a new one (Hitachi I think), with links to purchase, and how to install outside the original install site.

-- Ted

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TedSherman

18 posts in 1000 days


#11 posted 11-28-2017 01:36 AM

Hey all, I decided not to keep the Powermatic, so I’m selling it. I pasted below my Facebook sale ad.

I Have a Powermatic 3420B for sale, that has smoke damage and heat damage from an adjacent room fire. All electronics were destroyed. Lathe bed and headstock are ok with some smoke damage. Pulleys are good, no distortion, belt appears to be good, bearings appear to be good. I was going to rebuild myself, and started purchasing parts, but I just don’t have the time (or mechanical inclination). I have a several new parts: motor (Part 3520b-232), signal cord (JWL1642-170), digital readout and sensor (JWL1642-130A, JWL1642-130S), push-pull switch (6295839), and control pot assembly (6295915).
Price is $1200 firm in person (just want to get out what I put in).
Local pickup in Murfreesboro, TN.
Message me thru this post if you have questions.

-- Ted

View Nubsnstubs's profile

Nubsnstubs

1207 posts in 1569 days


#12 posted 11-28-2017 04:00 AM

You are so close, Ted. It’s a shame to give up. .......... Jerry (in Tucson)

-- Jerry (in Tucson) www.woodturnerstools.com

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TedSherman

18 posts in 1000 days


#13 posted 11-30-2017 02:58 AM

Thanks, Jerry, but I sold it tonight.

-- Ted

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