Auxiliary Table Saw Fence

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Project by onecarwallace posted 10-23-2013 12:41 AM 3749 views 0 times favorited 5 comments Add to Favorites Watch

A little backstory:

I’ve been learning to woodwork for a little over a year now and I’m just discovering my table saw’s limitations on my first real project. I’m building a shaker style nightstand and I’ve been having problems where I measure the distance from the fence to the blade and then the cut comes out too small. My table saw is a Bosch 4100. Yes, I know, it’s less than ideal for woodworking. Unfortunately it’s all I have room for in my 1 car garage. I’ll make the workshop a priority when I buy a new house some time down the road.

Anyway, I took a square to the fence and I found out that it is slightly off from perpendicular to the table. With the back of a square pressed against the fence, it rises 1/8” off the table surface at a distance of 6 inches from the fence. I guess that gives it an angle of 91.2 degrees. The other side is correspondingly 88.8 degrees off the table.

I called Bosch customer support and was amused to hear the guy tell me that if I want better accuracy than that, I should buy a Delta Unisaw. I appreciate his honesty but I was really hoping for them to send me a new fence. Anyway, I decided to fix the problem by building an auxiliary fence with set screws to correct the angle.

The fence:

The fence has a t-track in it for 1/4-20 bolts, which I used two of to attach a piece of melamine. Next to each bolt I put two threaded inserts, which accepted set screws. The instructions for the threaded inserts said to drill a 9/32 hole. I don’t have that bit so I went one bigger with 5/16, and that still ended up tearing out the surface a little. That tear-out shouldn’t make a difference. Maybe I wouldn’t have gotten it with hardwood. Anyway, the last picture shows that I corrected the problem.

I’ve read about lots of problems with the Bosch 4100 TS fence alignment, both with being perpendicular to the table and parallel to the miter slots. Luckily I don’t seem to be having an issue with parallelism, but this fence can fix both problems. I think my next task will be to build one of these for the other side of the fence, and then make a new tenon jig since my current one won’t fit anymore.

Hopefully the next project I’ll be putting up here will be my shaker table.

5 comments so far

View Jpedi's profile


100 posts in 2973 days

#1 posted 10-23-2013 01:37 AM

My guess is, unless you have DEEP pockets, you are going to have this scenario: pretty decent equipment for a reasonable price, PLUS some of your own ingenuity to get it working for you closer to perfect—which would have cost you a bundle if you wanted to start off closer to perfect. Does that make sense? ????

View onecarwallace's profile


19 posts in 2632 days

#2 posted 10-23-2013 01:56 AM

Yeah, makes complete sense. Of course the other limitation I’m finding is the motor. It has some trouble getting through 4/4 maple.

One day SawStop, one day…

View Jokker78's profile


148 posts in 2612 days

#3 posted 10-23-2013 04:03 AM

Check your blade. 4/4 is only an inch thick right. Could also be related to the fence issue too.

-- Measure once, cut , measure again, cut and damn its still to short

View kurtb's profile


10 posts in 3535 days

#4 posted 10-23-2013 12:57 PM

1-Car: That’s a clever way to address the inaccuracy of your fence. Good job!

I use that model of saw. On mine, it was difficult getting a good angled rip. After making lots of expensive firewood, I realized that the cheesy red clearance insert was the culprit. After I replaced it with a hardwood zero-clearance insert, the angled rips were much better.

Thx for sharing your fence innovation!

View onecarwallace's profile


19 posts in 2632 days

#5 posted 10-23-2013 01:24 PM

Kurtb, thanks.

I’m going to have to build a sled very soon since I’m building a table top for my shaker table. This should be a good opportunity to make sure the blade’s parallel to the miter slots. I’ve adjusted it before but it’s been awhile and it might need a tuneup.

I think my winter project might just be tuning up all my tools for the spring.

Also, I had the angles wrong in my initial post. The fence was off by 1.2 degrees, not 0.12. It seemed a little low when I posted it.

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