Miters on the Bosch 4410L

[Chris Jenkins]

I'm gonna be building a nice maple box as a gift. I was planning to do miters reinforced with dovetail keys.

So last night I break out the 4410L for the first time since the move and check it for accuracy. Blade is square to the table. DO a test cut, flip the ends to double the error and everything is good. Rotate the head over to 45 degrees. It was off just a bit, so I used the micro adjust and get it corrected. SO then I do another test cut and here is the problem, now that the miters are 45, the cut is not square!

I fooled with it to the point that I was just enraged. Walked away for a bit and then came back to it thinking lets try a bevel instead of a miter.

I cut the bevel and it was properly cutting 45, but there is a hollow in the cut, so if you were to put to miters together you get a 90 degree angle that the ends coming together at the top and bottom, but are coved out in the middle something like this ().

I took them to the block plane and this will fix the problem, but should I have to do this?

I would have tried this on the TS, but I really don't like taking my saw out of square and the lumber is taller than the height of the blade max.

Any suggestions would be great.

Thanks,

Chris

[Peter Pedisich]

could it be a thin-kerf blade flexing?

my dewalt came with a thin kerf and when i replaced it with a full kerf with a thicker plate the bevel cuts in particular were more accurate.

[glenn bradley]

The 90 v.s. 45 sounds like some fine tuning of the stops is required. The coving sounds like blade flex. Try soft v.s. hard wood, if the symptoms are worse on hardwood this would increase my suspicion of blade flex. If you are using a full kerf blade I would try the cut very slowly to make sure the problem is not being amplified by the rate of feed.

Don't you wish we could just say "flip the straight switch" and make everything OK?