Wednesday, June 13, 2012

Fixing a Tablesaw Fence

This post might be really boring to you, if you're not into tools. Wait - what are you doing reading this blog if you're not into tools? Seriously!

The fence on my SawStop has been giving me headaches. It had more dips and valleys than - well, fill in the blank here. When I would try to cut a board, you could literally see all the humps on the fence, and the cuts weren't all that accurate.

Here's the offender - so I removed that white laminated piece on the left, to see what the actual fence frame looked like.


When I put a straightedge up against it - I could see daylight. It's bent? Really?


A feeler gauge slips right into that gap


and determines that the fence is bowed .018 of an inch.

Now I'll say this - SawStop is very good about covering their saws. VERY. I've had three different models in my school, and their technicians have never failed to get me the parts I need to fix things.


But - this repair was a little different. First - this saw is out of warranty, and second - I suspect that the fence was bent through some sort of user error. When you have 20 or 30 people using your tools each week, things are bound to take some abuse.

One of the things I really preach to my students is about learning to fix things yourself. Channel your inner McGuyver, it will save you money, and you'll actually learn how your tool works, from the inside out.

In this case, I knew I needed to shim out the fence a little bit. I tried to use a couple of small pieces of plastic laminate, but they ended up being too thick, so it sent the fence bowing too much in the opposite direction.

Then - of course - Danny to the rescue!

He suggested using some plastic laminate backer paper, which is thin and strong. He even had a piece of it that I could use.


I cut a few small strips,


and marked the hollow spots on the fence with a couple of dots of blue tape. That indicates the area that needs shimming.


As I located the low areas with a dial indicator (thanks for the loan, Eric!), I placed a shim of the backer paper between the metal frame and the fence, thus bringing the fence into a flat plane.


If I put the dial indicator against the fence and zero it out,


and then move it to a different position, it will show me where there is a hollow spot, or a bulge.


In this case - those shims really did the trick! The indicator proved that the fence was flat all along the face of it, within just a few thousandths of an inch. Sweet.






Now toward the back end of your fence, you'll want to adjust it so that it is very slightly tapering away from your blade. You do that so the wood doesn't get bound between the fence and the blade. There is a very simple adjustment on all fences that allow that - so if your wood is burning toward the end of your cuts, you may want to check that out and make an adjustment. I tweaked mine with an allen wrench, and all was right in the (woodworking) world again.

All this fence manipulation can sometimes ruin the calibration on your fence, so the last thing to do was re-set it. It couldn't be more simple!

Just bring the fence right up against the blade - as close as you can get it. (It's not turned on, by the way.)


Then look down at the fence ruler - it should read absolute 0. You can see here that the calibration is off by about 1/16th of an inch.


No problema, chica! Loosen the screws, and readjust your pointer until it reads a perfect 0. And that's it - you've just flattened your fence and calibrated everything, in a matter of minutes.


Don't hurt yourself patting yourself on the back! Get back to work!

2 comments:

Michael Paxton said...

Jamie,

Your Mom's crazy, this post is awesome!

Chloe said...

I bought Dewalt DW175 miter saw two months ago. I have problem with cutting board 90 degree. Do you think I use table miter saw improve cutting boar? I want to d├ęcor crib for my daughter