Apex 20" sander rebuild

[Jonathan Jung]

I would like to put this disc sander back together. It's a 20" Apex 20-S serial 5600 (Rankin / Pal Industries) and the gentleman who gave it to me said it was a ~1990s model. It looks like everything is there, except the electronics and motor. I'm waiting for a call back from the Apex service tech, will see if they are helpful.

1 - is it worth putting back together with a new motor? There's an ugly blue machine on eBay, asking $1300, but it has nicer rack/pinion handwheel adjustments. Mine will need a motor, dust collection port, starter, and wiring. I haven't checked for disc runout.

2 - the base needs rotation about 180degrees, but I don't want to mess up the internal table lift balancer, or have the spring come flying out. Can I just remove the bolt/nut at the bottom to remove the base, or do I need to disconnect the cable or spring first?

3 - what size motor should I use? Similar units have a 2-3hp motor 1725rpm, and I'd use 3ph with a VFD for speed and directional control.

4 - where were these made?

5 - is the direct drive, bolting the disc on with a woodruff key, ever an issue with runout?

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[Jonathan Jung]

I reached out to ApexMachineGroup, but they are a different Apex. Is Rankin/Pal Industries/Apex still around? Would be great to get a manual or a parts diagram.

[Barry W. Larson]

Hi Jonathon.
It's been a few years (maybe 10 or more) since I sourced information/parts for my sander. Apex parts are/were handled by Davis and Wells, but I don't know if they are in business anymore. You might try the following (from the OWWM website):

Davis and Wells
310-767-6800 (Dan Malouin's cell number)
Davis & Wells machinery parts as well as used machines.

Hope this helps. Be safe and stay well.
Barry W. Larson
Calgary, Alberta, Canada eh!

[Maurice Mcmurry]

It looks much older than the 1990s to me. The potential is very intriguing. I think you will be on your own as far as support goes (I hope I am wrong about support). Is the the disc present?

This Dayton on eBay looks like the same machine more or less.

Dayton 20" Disk Sande 2XTG* Variable Speed VFD Single Phase 190735237427 | eBay (https://www.ebay.com/itm/352636725311?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&itemid=352636725311&targetid=1262749492222&device=c&mktype=&googleloc=1016367&poi=&campaignid=14859008593&mkgroupid=130497710760&rlsatarget=pla-1262749492222&abcId=9300678&merchantid=114176489&gclid=CjwKCAjwtIaVBhBkEiwAsr7-c9mjA3jkEs__dxXsy_kf40F7LjTITZAUpAiY2G6kei_4iVDCES IY3xoCUywQAvD_BwE)

[Jonathan Jung]

Thank you Barry, that is very helpful. I called Dan and he was the guy to talk to! He's still in the business. He is looking for a dust chute in his inventory and also helped with info on the machine. He recommends a 3hp motor if I want to use a VFD at slow speeds.

Answer to my 2nd question, I got it sorted out. Base is not straight, springs internally are aligned, and the table moves up and down nicely.

Answer to my 5th question, Dan said the motor shaft and disc flange and disc itself were all turned together at the factory. So with a new motor I may have to get it turned for proper runout.

All in all, it's a simple machine and since all the main components and castings are in good shape, I think it will be worth putting back together.

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[Barry W. Larson]

Hi Jonathon.
Glad to be of help. I should add that my Apex sander came with a replacement motor (I doubt Apex ever used WEG motors) which I replaced with a Baldor single phase - I should have gone with 3 phase and a VFD! The sander runs true with the Baldor motor, so I'd test it first before getting the assembly tried up or balanced. One thing I did do was mark the position of the disk on the hub so I can put it back in the same orientation each time (I remove it to replace the sanding disks). I assumed it was correct when I got the machine and as I said it runs true in that orientation. You might have to experiment a bit with yours if similar care hasn't been taken with the disk/hub in the past. Enjoy your sander, they are great units!

Be safe and stay well.

Barry W. Larson
Calgary, Alberta, Canada eh!

[Bill Dufour]

I made a simple disk sander from a pulley with a piece of solid core door screwed on. Rough cut rough the circle then turned it as it spun like a sander. That is probably how they did your machine just using metal cutting tools.
I would be tempted to do it on a lathe at the tailstock end. Bolt the motor up above the bed on a block carefully squared to the carriage.
Don't have a metal working lathe? A die grinder can do limited metal removal. See "tool post grinder" for ideas.
Bill D

[Jonathan Jung]

Anyone know what motor mount I need to look for? Since the disc is direct mount, the motor and it's support need to be very sturdy. It seems that 140 series mounts use 7/8" shaft, which I need, whereas higher number mounts use 1-1/8" shafts. I just want to ensure it's a stiff mounting option. I think it would need something like these, but I'm not 100% sure what frame to look for:

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Or will a more standard frame mount, such as 145 be sufficient, like this?

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[Mike Kees]

Jonathan, congrats on that machine. You are on quite a roll here. I just read your bandsaw thread where you found the Felder . Think about keeping your 17'' saw if you have the room. I sold a 18'' Steel City when I bought my Centauro 24'',wish I would have kept it. Anyhow a couple real nice additions to your shop.

[Bill Dufour]

Probably just a standard NEMA mount. Just match the mounting holes The shaft diameter is not fixed to frame size. The disk can be bored out to take a larger more solid shaft. On my Rockwell 12" disk sander the disk mount can be separated from the disk and easily bored out on a lathe. making a new keyway is the only issue.
Bill D.

https://www.engineeringtoolbox.com/nema-electrical-motor-frame-dimensions-d_1504.html

[Bill Dufour]

Looks like you have several choices for motor mount slots. I would go as long and wide as possible. I would guess the shaft height can go up a 1/4" with no problem.
BillD

[Jonathan Jung]

Bill, thank you for the link, that's very helpful! I'll do just that. I know a guy that can bore it out. 7/8" diameter shaft seems small for a 20" disc, and I see that newer machines use 1-1/8" shafts, and there must be a reason, so I'll look into taking it to a machinist who's done work for me before.

Mike, thank you. Yes, I'll be keeping 2 bandsaws - I have 3 right now - a smaller machine for curves and the 24" for ripping.

[Ben Grefe]

Jonathan,

Before you spend a bunch of money refurbishing this thing and buying new parts, I suggest you watch the local auction here (I'm in Seattle, so not very far from you). I bought a 1990s era Wilton 20 inch disc sander fully working for $375 bucks a few years ago. I see the 20 inch sanders go for sale almost every month and they're *way less* than $1000. If you really want this Apex to work, then just source all the parts off of an auction buy - or just use that one instead.

[Jonathan Jung]

Ben, which auction? I used to watch Murphy Auction but the prices bidders are going to are sometimes more than new, so I stopped checking. I'm thinking if I can get a used motor for a couple hundred, then I'll have a working machine.

[Ben Grefe]

Yeah, murphyauctions.com. That's where I got mine and I've seen at least 10 more show up over the past year. Right now it looks like they have a disc sander going up, but it's a more substantial model. I know the auctions get bid up furiously in the last minutes, but I know I saw one go for $500 last year when I was still paying close attention.

[Bill Dufour]

I would get a three phase TEFC motor and a vfd to run it. The variable speed is nice I suppose but the soft start is worth it. No need for braking that I can see. Let it coast to a stop.
Bill D

[Bill Dufour]

On a big disk sander like that is there any advantage for having reverse? A three phase motor and a VFd can run in either direction with the flip of a switch. No fancy wiring needed. best to let it stop before reversing direction.
Bill D.

[Robert Hayward]

I find the brake useful on my 20" Powermatic disc sander. The disc will spin a little over 18 minutes on power off with no brake applied. The brake on the Powermatic is a small puck about 1 1/4" in diameter rubbing against the back of the sanding disc and activated by a hand lever. Not very effective with the disc at near full speed though. My model of the Powermatic does not have reverse. There are times I would like to use the opposite side of the disc and miss not having reverse.

The centrifugal switch on the motor starts making a ticking noise at about 100 RPM's. Takes almost five minutes for the disc to stop spinning once the ticking starts. Really annoying to listen to the ticking slowly wind down to nothing. When the ticking starts is when I am most likely to use the brake.