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Powermatic PM66 Cracked Trunnion

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Forum topic by Jim Y posted 12-27-2014 10:26 PM 1306 views 0 times favorited 5 replies Add to Favorites Watch
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Jim Y

8 posts in 1418 days


12-27-2014 10:26 PM

Topic tags/keywords: tablesaw question

Hello all,
The tilt and elevation on my PM66 have always been difficult to turn so I thought I would pull the top off and clean up the gears and lube it back up. When I got in there, I discovered that the trunnion support near the motor mount was cracked.

Needless to say I was pretty bummed. I called Powermatic and they suggested that I pull the trunnion out and get it welded. They were concerned with the crack being near the motor that most of the stress from the weight of the motor would be born on that area, so not repairing would be a bad idea.
My question is, is it safe to run like this? Were talking home use, not industrial. If not, can this be done without warping the frame? I’ve called 5 different places and most have been less than enthusiastic about the possibilities of success. Anyone have some experience with this? Not looking for pretty, just need to make sure this thing will be safe to run. I’m in Phoenix, AZ if anyone has a name to suggest.
Thanks
JY


5 replies so far

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Deycart

444 posts in 1724 days


#1 posted 12-27-2014 11:02 PM

Here is a crazy idea. You can excavate a bit and use JB weld to fill in the space.
http://www.jbweld.com/product/j-b-weld/

It’s rated at about 4000 PSI and its a completely cold process so warping to worry about. I have used this stuff to repair all kinds of stuff and I have NEVER had the original repair fail on me. Just be sure to clean the area thoroughly and make sure its dry.

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MrUnix

4234 posts in 1665 days


#2 posted 12-27-2014 11:34 PM

Even more crazy of an idea.. Marine-Tex. I’ve used it to repair cracked engine blocks and other cast iron parts. I tried JB-weld once on a cracked tractor exhaust manifold and it failed in pretty short order, but Marine-Tex worked and has been holding tight for over 10 years now. If you have some JB-weld handy, give it a try.. if it doesn’t work or you don’t have any, give Marine-Tex a whirl. Best repair would be to weld it, but it won’t hurt anything to give either of the two epoxies a try first.

Cheers,
Brad

-- Brad in FL - To be old and wise, you must first be young and stupid

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Jim Y

8 posts in 1418 days


#3 posted 12-27-2014 11:51 PM

Wow. Brilliant. I’ve been so focused on the weld/braze repair that I completely forgot about epoxy. I’ve got a couple of tubes of JB weld around the house. I’m going to look into the Marine-tex. Just got a quote from a company willing to braze it. $150+shipping (they’re in CA). This would be much cheaper.

So if I’m understanding you right, just grind out the area around the crack to expose fresh metal, then lay a bead. Do I need to worry about working it into the crack itself or will it pull in? Also, I may have gotten some WD-40 down in it when I was trying to loosen the dried, caked up lube on the trunnion ends. Maybe some brake cleaner or denatured alcohol to make sure it’s clean?

I think I have my afternoon tomorrow planned out!
JY

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Deycart

444 posts in 1724 days


#4 posted 12-28-2014 12:00 AM

I would use a general de-greaser and then some alcohol to make sure its clean. The JB failed probably because the manifold get really hot. It’s not rated for high heat.

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REO

889 posts in 1540 days


#5 posted 12-28-2014 02:56 PM

brazing and slow cool will most likely not distort your casting to the point of being unuseable. welding is dificult but not impossible. again preheat (900-1100) and cool very slowly.
on a peice that size keep it hot and throw it in the oven preheated to the highest possible setting (550) and then turn it down 100 degrees an hour.

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