Compound angles!

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414
Location
Seguin, TX
Jeezopete...

When I was working for the mesquite outfit, I built probably 200 simple, 'library looking' dining chairs. Nice straight frame... no splay from the rear to the front. When I started selling chairs on my own, I made the front a couple inches wide than the rear. Makes a better looking chair, especially when an upholstered seat is used. Buuuut, I haven't made any chairs in over a year. So I forgot my tricks. Long story short... I've always struggled with the compound miters and cutting tenons. Blade at an angle, miter gauge or sled at an angle as well... and then the mirror piece for the other side is upside down and backwards. So I use both miter slots. Today it dawned on me that the blade isn't parallel to the slots. :eek: I've got the sleds/gauges set up to cut square from the left slot, so I don't normally have any issues... but when I have to cut the dreaded compound angles, 3degrees from the left slot isn't the same as -3degrees from the right. :doh: It's soooo close that it's even more irritating than if it was way bad.

I'll be moving the saw in a couple months (hear that Norm??), so I'm not gonna spend any time on it now... but I'll be back for instructions later.
 
Jeezopete...

When I was working for the mesquite outfit, I built probably 200 simple, 'library looking' dining chairs. Nice straight frame... no splay from the rear to the front. When I started selling chairs on my own, I made the front a couple inches wide than the rear. Makes a better looking chair, especially when an upholstered seat is used. Buuuut, I haven't made any chairs in over a year. So I forgot my tricks. Long story short... I've always struggled with the compound miters and cutting tenons. Blade at an angle, miter gauge or sled at an angle as well... and then the mirror piece for the other side is upside down and backwards. So I use both miter slots. Today it dawned on me that the blade isn't parallel to the slots. :eek: I've got the sleds/gauges set up to cut square from the left slot, so I don't normally have any issues... but when I have to cut the dreaded compound angles, 3degrees from the left slot isn't the same as -3degrees from the right. :doh: It's soooo close that it's even more irritating than if it was way bad.

I'll be moving the saw in a couple months (hear that Norm??), so I'm not gonna spend any time on it now... but I'll be back for instructions later.

Uh....Uh.... I Tink I Heard a little Birdie trying to tell me something,:huh: ........ nah, couldn't be, ........ no pictures.:rofl::rofl::rofl::rofl::rofl:

(Guess who was represented Sunday at the Midland "Home Show" that the LOML drug me to)? I just saw them, there...... didn't stop to visit.;)

Boy, that's the PITS when the mitre slots aren't parallel to each other.:(
 
kirk,
when i need to cut matching angles that oppose one another on the saw i use a 90º sled with an angled wedge placed against the fence of the sled.
switch the wedge from one side of the blade to the other to get exact results.
 
I have a Jointech SmartMiter sled that adjusts 45 to -45... but what do you do when you need the blade tilt the other direction?? That's why I go to the right miter slot.
 
don`t use the sleds features.....by cutting a wedge you can use it against the fence to the left or right of the blade, even put it against the front board of your sled (if it`s 90º too).
 
Still doesn't get me the blade tilted the other direction. What you're saying will work on a single angle with the blade at 90degrees... but when there's a compound, you have to use the tilt of the blade... and I just don't see how you can do that without going to the other slot. The specific cut I'm having trouble with is a 12degree miter on the face of the board, with a 3degree bevel at the end (and the shoulder cut of the tenon).
 
Okay... I think I see you you're saying now that I've looked at a piece. I'd assume to compensate for the blade tilt, the piece being cut would have to sit ON TOP of the wedge... and somehow that seems unsafe to me (unless the wedge was attached to the sled... and maybe then, too). I may give it a try just to see.

Sometimes these things that seem simple to other folks are hard for me to grasp. :eek: Thanks for trying. ;)
 
If you adjust the miter angle of the sled to the runner, and thus to the miter gauge slot, rather than to the blade, your miter angle will be correct even if the blade is not parallel to the slot. The angle of the cut is controlled by the path that the sled or miter gauge takes as it moves in the slot and not the angle of the fence to the blade. The slot and blade not being dead on parallel will manifest itself in the quality of the cut and the width of the kerf made, but the cut itself will be at the angle of the fence to the slot.

If the cut end of the fence on the sled is square to the table, then you can easily mark the angle and location of the bevel on the workpiece, then use a wedge between the workpiece and and sled table at the end away from the blade to align the marked line with the edge of the fence and make the cut with the bevel of the blade set to zero. You could clamp the work to the fence or simply hold it in place as you make the cut.
 
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