Blade is not square at 45 tilt

[jrohrssen]

Hello!

I bought a used BT3100 a month or so ago and went through all the recommended setup procedures, but still can't cut 45 degree miters well with the saw. When the blade is set to 90 degrees it's spot on, perpendicular to the table, and perfectly aligned with the miter. When I tilt the blade to 45 degrees to cut miters the cuts are off just a bit as if the blade is not square any longer. If I cut the 45's with the miter instead of tilting the blade, they are perfect, but I can't do that for most of the miters I need to cut (for boxes for example).

Is there an adjustment to true the blade while it's tilted, and would that then affect the 90 settings?

[eddy merckx]

Hi jrohrssen

Are you relying on the calibrated gauge on the front of the saw to get 45 degrees? If so, it may not be set up properly. The stops for 90 degees and 45 degrees are adjustable. If you look under your saw, you can see the stops. Easy to reset.

I think most people use plastic engineering trianges to check the angle, then lock the stop down. That's what I did. Make sure to run some practice cuts to make sure you got it right.

I hope that helps. Eddy.

[Greg.B]

There are set nuts on the 45 side. Its just a matter of turning the nut. Very simple process. Loose nut lock blade, adjust to 45 with a triangle. Tighten nut. Done.

[LCHIEN]

Hi jrohrssen

Are you relying on the calibrated gauge on the front of the saw to get 45 degrees? If so, it may not be set up properly. The stops for 90 degees and 45 degrees are adjustable. If you look under your saw, you can see the stops. Easy to reset.

I think most people use plastic engineering trianges to check the angle, then lock the stop down. That's what I did. Make sure to run some practice cuts to make sure you got it right.

I hope that helps. Eddy.

I agree. The marking on the front is no guarantee.
Check the blade tilt with a good reference. Make sure you check aginst the blade body and not the teeth which may stick out some to the side.

[jrohrssen]

I guess I didn't make the problem clear. The 45 degree angle is not a problem, I used a calibrated triangle to set that, then set the stops. The problem is the blade is off front to back when at 45 degrees, causing the miters to be just a hair off from top to bottom. At 90 degrees the blade is perfectly square to the miter fence. The problem happens when I tilt the blade, then the measurements are off between the front and back of the blade relative to the miter. It's as if the blade and motor unit are twisting slightly when I tilt the blade.

I'm very new to WW and TS's so if I don't have the terminology correct I apologize.

I hope this makes the problem a little clearer for you all.

Jay

[gjat]

Interesting.

I would assume that you are moving the fence on the SMT back to accomodate the tilt of the blade.
Are you moving the SMT fence back and ensuring it's square BEFORE tilting the blade? NEVER trust the 'stop pin' for it to be accurate. Personally, I never use them.

Tilt the blade to 45 and make a pencil mark where you want the SMT fence.
Set the blade at 90, move the SMTfene back and make sure it's square w/ blade.
Tilt the blade to 45 and try cut.

If you still get out of square, then either your work piece is sliding, or the SMT fence is moving a skosh. Try cutting super slow so that you aren't putting any presure against the blade and see what happens.

[jrohrssen]

I'm not using the SMT, I use the miter table with an incra 1000, and at 90 degrees, the blade is perfectly square to the miter jig. Once I tilt the blade, it's off a hair, just enough to make the miters off. The miter table stays where it's at ( it's adjusted just right at 90 ). So the table isn't moving, just the blade assembly.

It's as if the assembly isn't pivoting quite perfectly.

[gjat]

It's possible it's not tilting squarely, but highly un-likely.

When you check square to the blade, are you checking at 1 point on the blade? For instance, check at the front of the blade (closest too you), make a mark, rotate that mark to the back, and check there.

If that's square, it may be techniqe. Check to make sure there is NO movement in the miter slot or miter fence and your workpiece does not slide at all (clamp it to the miter fence).

[Black wallnut]

There is a slight possibility that the "pins" that the Locker Bracket piviot on for bevels are worn since you purchased your saw used. That said I've only ever read of one forum member here or over @ Ryobi's forum in the years that I've been a member. That one person was Jim in Texas. Perhaps you could shoot him a PM and ask if this happened to him about the time he had to replace his pins, assuming he still remembers. Anyway that is where I would look.

[cgallery]

Been there. In my case, it turned out that the wood wasn't planed correctly (one edge was about 1/32" thicker than the other).

If I cut that piece of wood w/ the blade set to 90-degrees, the cuts came out perfectly square.

If I cut the same piece of wood w/ the blade set to 45-degrees, the cuts weren't square.

One way to test this quickly is use your square on the "inside" of the cut (the bottom of the bevel). If that shows square, but the other side isn't square, then the wood isn't true, or it isn't sitting on the table flat enough.

Good luck!

[cgallery]

Oh, and FWIW, I did learn that changing my blade from 90-degrees to 45-degrees does throw the alignment of the blade to my miter slot out by a few thousandths..

That is, if I have my blade set to 90-degrees and use my dial indicator to make my miter slot perfectly parallel to the blade (+/- .0005"--as good as I can get and exceeding the envelope for my digital indicator), and then change the blade to 45-degrees and check w/ the indicator again, I find the alignment to be off just a few (.002-.004) thousandths.

I think this is due to how the bevel mechanism supports the front of the blade/motor bracket, rather than the middle.

But it is close enough. And the blade is toed-out in relation to the left miter slot, which is fine as it prevents burning as I push the wood through.

[jrohrssen]

Thank you all for the replies, as I stated I am very new to woodworking so it may very well be technique. I'll mess with it some and try some of the suggestions posted here to see if it makes a difference. I haven't been clamping the wood to the miter, I'll try that first to make sure it's not just me moving the wood. Not sure about the planing, it seems to be ok, I'll run a board through a few times to check it. Since I have a low end planer, that could be an issue as well. Again, thanks for all the replies, I'll report back if I figure it out (it's probably just me, lol).

Jay

[eezlock]

angle cuts......

Sounds as if the motor is asqued...not remaining squarely mouted at the rear
when it is tilted from vertical (90 deg.) to bevel position. Check the motor mounts an see if they have loosened somewhat, may need realignment here.
eezlock

[jrohrssen]

You'll all be very surprised to learn that the problem was....me! After clamping the work to the miter and running it through, it's off very slightly, but much better now. Thanks for everyone's input.

Jay