Truing a Unisaw arbor

[Jack Hoying]

Hello again,
I have my Unisaw project pretty far along. I painted the cabinet today and reassembled the arbor with new bearings. I checked the face of the blade bushing and found it to be almost .009 off. I know that the right thing to do would be to take everything back apart and have a machine shop true up the arbor face. However, I don't have a handy local machine shop that would do this and I always try to fix things myself. I was wondering if anyone has tried to true up the face while it's on the saw, using an disc grinder or something similar while the arbor is turning. I've done a similar fix on a lathe faceplate and that turned out pretty good. I guess as long as I don't get too agressive, I can always have it done professionally later on if my work doesn't pan out.
Here's a photo of the saw in my spray room this afternoon with it's second coat of primer. I added the dust collection tube, using a 4" metal duct (about 2" long). I used thickened epoxy to make a fillet on each side of the duct to fasten it securely in place.

[Bart Leetch]

Take the time right now to have it done right by a machine shop. You have the saw apart & trying to do it your self will only make the job harder for the machine shop. Waiting just a little longer will be worth the time spent. don't be in a hurry. I got my Unisaw Dec 18 2004 & didn't get it in the shop until sometime in Feb. If I had to take more time I would have its worth it.

"Remember I'm pulling for you we're all in this together."

Red Green

[Dev Emch]

Oh Boy, now where using quotes off the Red Green show. Since when did high quality television such as the Red Green show and Mr. Bean become relevent on this forum? I think this is great!

According to Mr. Bean, the quickest way to paint your saw would be to leave an open container of gray paint in your paint booth with the unisaw. Then insert about 20 or 30 M-80s with a concurrent fuse, light the fuse and run. Make sure the door is closed.

Humor aside. The trueing of this item is best done with a metal lathe. Your off by the thickness of three human hairs. Best bet is to find a machine shop in your area. Start by looking up machine shops in your phone book and call about. Electric motor repair shops often have metal lathes and milling machines as well. So this is another avenue. Lastly, if you can find a home shop machinist with the skills, you may be able to get him to do it. But be careful here. Just because some fellow has a metal lathe does not mean he actually knows how to use it. If you wish to post a machinist wanted advertisement, check out the machine board at www.chaski.com and mouse on over to the bulletin boards. You may have to join but its free.

Best of luck...

[David Eisan]

Hello there,

Because of the design of a Unisaw arbor, it can be turned in the bracket.

Loosen the bolt that holds the arbor bracket onto the raise lower shaft and take that assembly to a machine shop. They should be able to chuck the arbor between centres while it is still in the arbour bracket. Because of the design of the arbor, turning it place is the best thing to do. Pressing the shaft in with the bearings can sometimes distort the arbor and this ensures the runout is >0.001. I had one of my Unisaws done this way.

David.

[Roger Everett]

I would certainly have it done at a machine shop. Don't forget any untrueness in the flange is increased by 5 X at the edge of a 10" blade.
Roger

[Bruce Page]

Jack, with the face flange out .009, the first thing that I would want to know is if the arbor shaft is somehow bent (I suspect that it is). The best way to check this is between centers on a lathe using a test indicator. The shaft can also be checked by rolling it on a known flat surface and checking with a feeler gauge or in a pair of matched V-blocks using a test indicator. I have successfully straightened shafts by applying heat with a torch to draw the material back, but it is a hit or miss process. As already mentioned, trying to flatten the face with a die or right angle grinder won’t work because you will follow the existing out of tolerance flange face and will likely make things worse, we’re talking thousandths here, and the flange face needs to be perpendicular to the shaft within .001 on an inch. In any case, the shaft needs to be reworked with the proper equipment and machine shops don’t work cheap. At around $90 for a right tilt, you might be better off just replacing the shaft

[Dev Emch]

Bruce.....

I agree with you on this! Have any of you ever "BENT" a unisaw arbor shaft? If so, how?

Dave, that is an interesting process of turning the thing insitue on the lathe. I will remember that. Your right about possibly picking up some error from the bearings.

Concentricity errors are a very complex subject and a real pain in the posterior for woodworkers. Spindles look very easy to make on a lathe..... I can assure you, they are not! And it boils down to manageing your concentricty issues. Whole books can be written on this topic alone.

[David Fried]

Jack,

There is a place in Springfield, MA. that does Unisaws and does arbors by mail. (Just to give you more options and a base price)

From their web site (www.sawcenter.com):

"Delta Unisaw Arbor Rebuilding

The Saw Center offers a special service to owners of the Delta Unisaw. Send us your arbor assembly and we will rebuild it for a special low price of $89.95 plus shipping. This price includes the following items:

Disassemble & cleaning of all components
Replacement of ball bearings with a matched set of new bearings
New bearing spacers , and key, as needed.
Refacing of arbor flange, if needed.
If other parts are needed, we will notify you first.

Turn-around is usually 2-3 days."


Good Luck and keep posting pictures!



Dave Fried

[Jack Hoying]

Thanks to everyone who replied to my question about the arbor. While I do think that a machine shop is the best option, I couldn't resist trying to true it up myself. Since I don't have a motor for the saw yet, I clamped the whole tilting assemble to the legs of my band saw and took the belt from it to power up the arbor. As the arbor spun I ever so lightly used the disc grinder on the face (having the grinder firmly braced). I would grind a little, check the progress with a dial indicator, then grind a little more. Within 5 minutes, I had the face within .001. I polished the edge up with some sandpaper that was glued to a piece of metal. Later, I reassembled the saw and checked it out with a blade in place. I realize that I may of just gotten lucky, but I think that I have a very true machine.
Jack

[Bruce Page]

Jack, that's great! Did you take pics? I'd love to see that setup.

[Russ Massery]

I know for a fact the the arbor flange was cut at the factory while it was in the saw. They had a fixture that cut it after the saw was assembled. They used to put it in there ads years ago. The machine shop I work for was bidding on the contract to machine them. They wanted to do away with this process.

[Ken Shoemaker]

Jack,
You are my hero. Even if it's just having the sack to attempt such an operation. Now you have saved the cash to spend on somthing REALLY cool.

My hat is off to you.... Ken

[Jack Hoying]

Jack, that's great! Did you take pics? I'd love to see that setup.

I have been taking photos all along, but that's one I didn't do. The setup looked so much like a hillbilly's dream that I wouldn't of been too proud of it anyways.
Jack

[Andrew Ault]

The setup looked so much like a hillbilly's dream that I wouldn't of been too proud of it anyways.

BUT, it worked. Good going!

[Ken Fitzgerald]

Jack.....becareful what you say about hillbillies!