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View Gaffneylumber's profile

Table saw trunnion crack

by Gaffneylumber
posted 12-04-2016 07:42 PM


17 replies so far

View Loren's profile

Loren

10395 posts in 3647 days


#1 posted 12-04-2016 08:57 PM

contractor saw trunnions are often pot metal,
but whether they are that or iron, the trunnion
can be welded by a shop that does such work.

As an alternative you may be able to find a
trunnion from a scrapped saw on ebay.

View crank49's profile

crank49

4030 posts in 2970 days


#2 posted 12-04-2016 09:09 PM

If it’s cast iron the best bet may be to braze it. A good welding shop would know.

View Gaffneylumber's profile

Gaffneylumber

102 posts in 827 days


#3 posted 12-04-2016 09:15 PM

Thanks Loren it may very well be pot metal. What would be your thoughts on using an epoxy like jb weld in the crack? I know that stuff is supposed to be pretty strong and will adhere to metal. I could get complete coverage in the crack with the liquid version. My friend only has $140 in the saw and is trying to get out as cheap as possible.

-- Grayson - South Carolina

View Loren's profile

Loren

10395 posts in 3647 days


#4 posted 12-04-2016 09:18 PM

I’ve had mixed results using JBWeld in stress
areas but it may be worth a try, especially
if you can drill and tap a couple of holes
for a steel mending plate somewhere along
the crack.

View knotscott's profile

knotscott

8014 posts in 3374 days


#5 posted 12-04-2016 10:24 PM

The older Jet contractor saws were made by Mao Shan, and were nearly identical to the older Grizzly, General International, Omega, Ohio Forge, King, Bridgewood, PM, and many others. Maybe you can find an old donor saw on CL.

-- Happiness is like wetting your pants...everyone can see it, but only you can feel the warmth....

View Carloz's profile

Carloz

1147 posts in 590 days


#6 posted 12-04-2016 10:27 PM

I would not advice anyone using a table saw which was glued together.
At least “your friend” learned what craigslist is.

View splatman's profile

splatman

586 posts in 1398 days


#7 posted 12-04-2016 10:31 PM

Mending plates or, if you could drill thru the entire part, (1.) perpendicular to the crack, apply epoxy, then run a bolt thru the hole and tighten it down good.
Might not need to drill through the entire part; (2.) only drill though one 1/2, and an inch or so with a smaller bit into the other 1/2, then thread the smaller-diameter hole.
Apply epoxy to the crack and the repair hardware to make doubly sure this will not come apart again.

View MrUnix's profile

MrUnix

6714 posts in 2198 days


#8 posted 12-04-2016 10:41 PM

Lots of ways to fix cracked parts pretty easily, but before doing anything, you need to figure out what it’s made out of and go from there. Maybe post a picture or two as well :)

If it’s cast iron… it’s easily welded, which is the preferred method.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

View corelz125's profile

corelz125

394 posts in 975 days


#9 posted 12-04-2016 10:41 PM

It’s not going to be cheap to weld it. Cast iron is tough to weld and some people don’t know how to weld cast. My trunion cracked on my saw when I first brought it home but it was brand new and was covered under the warranty.

View MrUnix's profile

MrUnix

6714 posts in 2198 days


#10 posted 12-04-2016 10:53 PM

It’s not going to be cheap to weld it.
- corelz125

Hmmm… around here, a welding shop would charge maybe $25 to braze a small crack. Certainly cheaper than trying to source a new bracket for an old machine like that. I’ve even fixed cast iron a few times using standard ER70S wire in a mig welder, which basically cost me nothing but about a half hour of my time. YMMV.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

View SignWave's profile

SignWave

440 posts in 3034 days


#11 posted 12-05-2016 02:37 AM

I’ll echo that brazing is the best choice for a crack like you describe. Brazing works best when you have a good size surface that mates together properly, and it sounds like you do. It isn’t all that difficult and should end up at least as strong as the original part, and it will be permanent.

If you use adhesives like epoxy, it will probably fail eventually if it works at all, and it will prevent a proper repair later.

Before I had a welder, I had a couple of small jobs done at a local muffler shop (not a chain). The cash price was very reasonable.

-- Barry, http://BarrysWorkshop.com/

View Gaffneylumber's profile

Gaffneylumber

102 posts in 827 days


#12 posted 12-05-2016 02:42 AM

Thanks guys for all the insight and advice. If it were my saw I would probably go the welding route but my buddy sent me this pic and said he decided to epoxy it. Thanks Loren and Splatman for the mending plate idea. He said that he will add one for extra support.

-- Grayson - South Carolina

View bigJohninvegas's profile

bigJohninvegas

448 posts in 1461 days


#13 posted 12-05-2016 03:07 AM



It s not going to be cheap to weld it.
- corelz125

Hmmm… around here, a welding shop would charge maybe $25 to braze a small crack. Certainly cheaper than trying to source a new bracket for an old machine like that. I ve even fixed cast iron a few times using standard ER70S wire in a mig welder, which basically cost me nothing but about a half hour of my time. YMMV.

Cheers,
Brad

- MrUnix

I agree with Brad. $25 at a weld shop for sure. Don’t give up if the JB weld fails.
Scary fix, good luck.

-- John

View corelz125's profile

corelz125

394 posts in 975 days


#14 posted 12-05-2016 03:08 AM

There’s a difference between welding and brazing strength.

View SignWave's profile

SignWave

440 posts in 3034 days


#15 posted 12-05-2016 02:02 PM

Sometimes you have to just choose a path and run with it. I hope it holds well.

-- Barry, http://BarrysWorkshop.com/

View Lazyman's profile

Lazyman

1964 posts in 1386 days


#16 posted 12-05-2016 02:25 PM

Hmm. If there was enough stress there to crack the metal, how likely is it that a JB Weld repair will hold up.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View Gaffneylumber's profile

Gaffneylumber

102 posts in 827 days


#17 posted 12-05-2016 03:31 PM

Lazyman, I see what you mean but hopefully after he adds the mending plate it will give a little more strength. It’s hard for me to see this cracking under normal operation. I wonder what caused this

-- Grayson - South Carolina

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