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I'm slotting fingerboard on a table saw. Something seems to have changed but I can't figure out what. Without going into details, here's the bottom line:

To get square, 90 degree cuts from the right side of the blade, the saw needs to be aligned perfectly straight.

From the left side of the blade, the jig needs to be slightly misaligned.

I've been cutting and adjusting for the last 4 hours and can't figure out what's going on. My jig runs in both miter slots. I put an indicator on it and the slots are aligned to the blade within .001", if you can believe that.

The front of my jig is dead flat...checked that.

I can not for the life of me figure out what possible difference it could make what side of the blade I'm cutting from.

Has anyone ever run into something like this? I can't imagine the blade's dull. I think this one only has maybe 10 fingerboard on it.



Anyhow, just looking for ideas and things to check, This is really driving me nuts.

Well, never mind. I figured it out. Time to dump the old Delta...probably replace it with a nice old radial arm saw. The arbor's got so much play in it as to be laughable. It's just wobbling around. From the right side, it wobbles away from the cut, leaving the nice straight line of the cut alone. From the left side, it wobbles INTO the cut and knocks everything offline. It also explains why my last two guitars needed glue to keep the frets nice and tight. I thought I was just doing something stupid, but the wobble was randomly widening the slots.

So there you go.

My dad has rebuilt the trunnion in several old table saws. Couple new bearings and your off and running.

I hear what you're saying, but I already sink too much time into adjusting machinery. I've fiddled with this one on and off for years trying to get it to tighten up and stay that way. I just have too much going on to be doing that anymore. Hey, 15 years isn't bad out of a cheap, abused contractor saw.

I have a lot more faith in the accuracy of a good table saw than any radial arm saw.

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John

Yo, John,
Your jig face is dead flat...but to what? The jig floor? The miter slot? Is the miter slot dead parallel to the blade path? Does the blade spin true in thin air, or does it wobble in thin air? (Blades can warp if they ever overheat. If so, they will wobble. It has happened to me, but not in a while.) It's pretty easy to adjust a saw table so the miter slot is parallel to the blade path. I've done it. It's not all that hard to change out arbor bearings. I've done that, too.

Don't freak out just yet. Address these things one at a time and start with the basics. Make sure the blade runs true and doesn't wobble when it's spinning in thin air. Then go to your miter slot (table alignment). Then go to your bearings last of all.

I think you can figure this out without changing saws. Unless, of course, you are just looking for an excuse to buy a new saw. In that case, go for a new saw! Who wouldn't want a new saw?!

Pat

I use a Dewalt portable table saw. It's accurate enough for me to slot 6 string bass necks perfectly. I haven't slotted anything wider.

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Old growth, shmold growth!

In the interest of at least seeing what was going on (but I knew it was bad because it wasn't just loose....it was "click - click" loose), I flipped it over to have a look.

This is an old, crappy direct drive saw. There is a big bracket that come off the trunion. The motor/arbor assembly sits on another bracket, and it attaches with a pin. The whole thing pivots on the pin for height adjustment. It's this pinned joint here that is loose. There's no way to tighten it...it's just a hole and a pin. Parts aren't even available anymore.

I suppose I could take it all apart, ream the holes, have a close tolerance pin made, reassemble it, and go looking for what else is wrong once this is tightened up, but it just doesn't make any sense.

I was thinking the same thing. A well set up RAS should be precise enough for most things, but I don't think that includes fret slots.

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Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

Builders have been using radial arm saws on fingerboards forever. If your RAS isn't more precise and repeatable on crosscuts than your tablesaw and sled, there's something wrong with your RAS or it's cheaply made.