How parallel should TS blade be to miter slot?

[lawhoo]

Based in part on the suggestion of several FOG members, I recently bought a Bosch 4100 table saw.  My primary purpose was to do repetitive rip cuts, such as for face frames.  I need the portability of a benchtop saw, because I'm having to share the garage with two cars, and I love the Gravity-Rise stand and the riving knife/blade guard.

In the course of setting up the saw, however, I measured the blade to ensure that it was parallel to the miter gauge slots.  To my surprise, it turned out to be about 0.025" out of alignment.  I followed the manual's directions for adjusting the blade's alignment, but the alignment brackets seemed designed to prevent adjustment, because the holes for their bolts aren't slotted.  The result is that retightening the bolts simply returns the blade more or less to its original misalignment.  I called Bosch and was told that a misalignment of 0.010" was within their specs, because the saw is considered a contractor's saw.  They also confirmed that, unlike the 4000 saw, the 4100 is not designed to allow such adjustments.  I hate the idea of disassembling and packing up the saw, but this bothers me.

Should this be a big enough concern to return the saw, or should I just adjust the fence and miter gauge to be parallel/square to the blade?  If you advise returning the saw, should I take my chances with another one or look elsewhere?  Thanks for any feedback.

 

[Michael Kellough]

You'll never get clean (burn free) cuts cross cuts with an out of parallel miter slot.

On the other hand, even if it was perfectly parallel cross cuts on the table saw won't be as good as with the Festool CS and MFT.

You could just consider the TS a ripping machine and forget about the miter slot, just use it to lock a feather board in place.

Or, ream out the bolt holes and make it adjustable, or return it. I'd probably return it.

 

[Daviddubya]

Most of the time when this question is asked, the answer I see is that the blade should be within a few thousandths of parallel with the miter slot - .025 is certainly way out of alignment.  On my cabinet saw it is within .002.  If Bosch says .010 is their spec, then I guess that is your answer for this saw.  Personally, I would not be happy with that answer, but that's me.  I suppose you could adjust your miter gauge to square with the blade and your fence to parallel with the blade and use it that way.  Or as Michael suggested, ream out the bolt holes to get the adjustment you need.  If you like the saw, that's what I would do.

 

[Michael Kellough]

....I suppose you could adjust your miter gauge to square with the blade and your fence to parallel with the blade and use it that way....

This only works if the alignment error is less than the set of the teeth (with a carbide blade the thickness of the teeth compared to the thickness of the body divided by 2) and the wood is narrow enough that the cut is finished before you get to the back teeth. Otherwise, you get burning at minimum, or, additional undesired cutting. Not even a crosscut sled will solve the problem.

I have a just barely tolerable problem of this kind with my old TS. If the capacitor replacement doesn't get the motor going again and I have to drop the motor I guess I'll go ahead and take it appart to fix the alignment too, which in my case means enlarging the key slots the trunnions fit into.

 

[lawhoo]

Thanks for the advice.  I'm pretty much set, as I was originally inclined, to return the saw.  I like several features of the saw, but I don't think I should have to make such fundamental changes to a brand new saw just to make it cut accurately--assuming my changes would work.  I'll probably end up biting the bullet and getting a decent contractor's saw (e.g., Ridgid 3650), even though it will take up more space and be less mobile than the 4100.  I know there are other benchtop saws out there, but I prefer the greater accuracy and adjustability of a "stationary" saw.  Since I have the TS55 and a miter saw for most crosscuts, I doubt I'll spring for the extra cost of a hybrid.

I will say that Bosch has been decent to deal with.  Apart from the problem itself and the hassle of having to repack everything into the original box (don't ask me how I'm going to do that), they've said they'll let me return the saw for a refund, even though I didn't open it and discover this problem until more than 30 days had passed.

 

[Michael Kellough]

Since I have the TS55 and a miter saw for most crosscuts, I doubt I'll spring for the extra cost of a hybrid.

Not sure what a "hybrid" is but you've got a lot of functionality already. You pretty much only need repeatable narrow ripping function so (if I were in your position) I'd take another chance on a small TS. A lot of people like the Rigid and Dewalt saw and if you get a good sample, the Bosch would be fine too.

 

[Loren Hedahl]

I have found that for almost everything power tool related, except for Festool, I end up in the re-manufacturing mode to get the accuracy I want.

My Ridgid contractor saw (earlier model than the one presently being sold) had an arbor flange that caused a 10 inch blade to wobble about 0.035".  A day of measuring with a dial indicator and filing got it down to nearly 0.001"

I also had to elongate holes to get the needed adjustment for making the blade run true to the miter gage slot.

The fence wouldn't stay in adjustment, so I roughened up the mating surfaces with coarse sandpaper and glued them with epoxy while making an accurate adjustment.

The table wasn't flat, so I ground it flat with a large disc sander.

With Festool stuff, it's a different story.  You pay more, but you get a product that works as it should right out of the box, in my experience.  I can also say the same about Lie Nielsen and Veritas planes and even a Harbor Freight 3/8 inch drill that I bought for around twelve dollars plus tax.

Now it makes a beautiful smooth cut, either ripping or cross cutting.

 

[brandon.nickel]

I've got a Jet table saw which I've managed to get within about 0.005" of parallel.  It came about 0.025" out.  It's not designed for precision adjustment (with lead screws on the trunnion), so it's a case of loosening three bolts, tweak, re-tighten, measure, loosen, etc, repeat until tired.  I've never hit it closer than 0.005" though I've hit that in both toe-in and out.  That just varies which side of the wood burns.  I generally choose to burn the left side of the blade because I only use the saw for ripping and that makes the burn on my cut-off.  A quick pass over the jointer (0.025") and I can make another rip.  Parallel would be better.  That's why I'm saving up for the SawStop (yes, you've heard it before).