Cracked Delta Unifence

Hi Everyone! Been Lurking for a while, and find a lot of solutions here for projects I am working on =)

I just picked up a Delta Unifence and contractor saw and was not thorough enough when checking it out.

It has a hairline crack in the body of the fence. Everything still seems to be square and straight. I drilled a hole to prevent it from spreading, but was wondering if I should attempt to repair the crack?

I believe it is cast out of Aluminum. Any recommendations on the best approach to take? Should I just leave it? I am worried that any heat will warp it.

Thanks!

Only you can tell if the crack is weakening the fence support enough to cause deflection?
If it is deflecting somewhat, it is often possible to screw a patch on one side, which would probably be strong enough.

Personally, I'd be more inclined to clean paint off the area, Vee out the crack (with burrs, not abrasives), fixture the part, clean scrupulously with a stainless brush & products made for the process, and TIG weld it. Do it well from both sides and the top surface can be filed to blend and become completely invisible under paint.

There are also aluminum solders that work astoundingly well, don't require melting the base metal, and might cause less distortion. Sold for refrigeration apps and repair. I have never fixed a casing with such, but did weld a former GF's aluminum car radiator with success.

How much does a new part cost?

smt

I don't have a tig setup but could take it to get tig welded somewhere. I am worried the heat will warp it, which is where I was hoping for some insight.

I was thinking about v-ing it out like you said and using some alumiweld/solder. Not sure if even that amount of heat would cause problems.

A bolted or riveted patch may be a good approach.

The part is no longer made and is not even available as new old stock anywhere.

I've used aluminum solder only a couple times, but it worked well, though not in a wicking situation like this. Methinks any distortion would be minimal with either of Stephen's suggested processes, esp TIG, since the contraction of the weld will pull the two pieces back together.

FWIW, Plaza Machinery has a Unifence listed for $300 at www.plazamachinery.com. Scroll to woodworking machinery list, then under "for tablesaws". Wouldn't be surprised if Joe had a casting somewhere, too, but repair does seem a more attractive option.

neil

OOPs-

Neil - I did not actually edit anything. Still forget my super-dooper-editor-moderator powers and hit "edit" with my thick fingers instead of "reply". Sorry to everyone.


To the OP: If they are that rare and expensive, I would probably not trust it to the local welding shop unless I had made the fixtture, mounted the part, prepped it, and carried it in. Not saying they can't do a perfect job - most can. But for some reason, machinists and weldors seem to think "ah, it's just for woodworking, does not really matter and they don't want to pay much anyway". You would probably get a good weld. But you need to really sound out the guy doing the work to be sure he wants to make you a solid, stress-free repair with minimal warping. If he is willing to explain in a non-condescending or hurried manner how he will weld it and fixture it, or steps he will take if not fixtured to minimize warping, you should be ok.

But it sounds like a screwed on aluminum or bronze patch might be the best option, & certainly cheap. Suitable thickness, good contour and contact, JB weld under it when assembled, and screw it together with say a couple/3 #6 or #8 machine screws on each side spaced so as not to create another line of potential cracking. You could make it look quite attractive in a steam-punk way, too. Or as an alternative, maybe engrave your name and logo on the patch with some filigree and a border, on a Gorton before assembling, etc.

smt

I have a complete unifence takeoff from a 10" cabinet saw available. $75 plus crating and shipping, but I would rather local pickup. Shipping company or method will strictly be your choice.

whhjr

neilho said:

I've used aluminum solder only a couple times, but it worked well, though not in a wicking situation like this. Methinks any distortion would be minimal with either of Stephen's suggested processes, esp TIG, since the contraction of the weld will pull the two pieces back together.

FWIW, Plaza Machinery has a Unifence listed for $300 at www.plazamachinery.com. Scroll to woodworking machinery list, then under "for tablesaws". Wouldn't be surprised if Joe had a casting somewhere, too, but repair does seem a more attractive option.

neil

Click to expand...

I read on another forum that Joe from Plaza Machinery passed away. The website advises they are closed until further notice. Sad news as Joe was nice man...

Thanks for the update.

Agreed- so sad, such a nice guy, good friend and good resource that struggled (gracefully) with so much cancer in his family. Not quite sure where to inquire for more news since I don't have contact info for the rest of his family.

Neil

Buy the used one. If I remember correctly there is almost no room for an applied patch. Underside of pic has a machined surface and exposed side that shows the crack has scant clearance over the rail. Nothing short of a V weld will work. And my guess is that the casting may need to be heated too.

WHHJR: I think that just might work. I wasn't planning on buying anything lol, but that is a good price for sure. How long is the main rail? Can you email me a few photos?

stephen thomas: A lot of good points to mull over, especially about how to approach finding the right person for the repair.

Plaza machinery sounds like an awesome place to walk around and waste a day. Sorry to hear the owner has passed away.

If it were mine I would reinforce it with a metal "splint" held on with epoxy and flathead screws in tapped holes. The metal patch would have to be shaped to fit but that is a matter of bend and test fit.

Here's what I would do.

Lightly V out the crack, mainly to get a better look. Remove all paint where the patch will go. Degrease everything with a non oily solvent making sure to flush the crack with solvent.

Get a clear, non-filled rigid epoxy such as sold in packets by McMaster and others. Put some on the crack and heat it with a heat gun until it thins and runs in the crack. Wipe off excess and leave it alone for a while.

After the first epoxy has hardened clean the area again, sanding if necessary. You want a good cross hatch for the next step. Using J-B Weld or other filled epoxy lightly clamp the repair patch and wait for it to harden.

Now come back and drill/tap/countersink for some flathead screws and install them with epoxy to be permanent.

While I agree that a skilled TIG welder can weld it without warping the typical weld shop will just weld away to get it done quickly. Since the method I described is plenty strong enough for a saw fence and it seems usable without repair I think my method is the least likely to cause problems.

Post # 6 is the easiest option and probably not more expensive than skilled TIG welding when you count your time, travel, and the possibility some machining might be required after welding.

When you look at the forces in play you will see that only a solid and perfect weld will work. Maybe not in this world. There is maybe a space for an 1/8 thick splint to run under the entire width of the base, full left to full right. Bridge the opening in the middle. Every time the fence is clamped that crack is pulled open. Adjust clamp for tighter grip, open it more.
In this case airplane glue and clothes pins ain't gonna work. Crack is there because that area is a stress riser, and the fence clamp was adjuster to tight and something bad happened.

I would bet this has been cracked for a while. The nice thing about the Unifence is you don't need a lot of clamping force. I see some guys just push down as far as they can on the handle. You don't need to do that just a light clamp and it will not move. If you can't get it tigged up then use as is for a while and see if it gets worse. Look for a used one at the same time.
Cheers
Martin