New spoilboard done

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Okay I just went back to the shop and ran some measurements, Iā€™ll do some futher test cuts later today with interim measurements (measure after the clerance path)

I made measurements of three different boards, one was cut with a router table using a 1/4" clearance and the matchfit bit using the matchfit jig to set heigh, the other two were cut with the altmill, one the test board, one the spoilboard, both clearanced and then cut with the matchfit bit. Mesaurements are the width at the very top (narrowest width) and the depth meaured with the caliper sitting on top of the board and putting the depth gauge in

Router table board: width is 0.344" and depth is 0.3675" the matchfit bit is a fairly snug fit in this board, the bottom of the dovetail (widest bit) is around 0.46"

Test board: width is 0.3675" and depth is 0.3675" and the matchfit bit isnā€™t as snug in this

Wasteboard: width is 0.3690" and depth is 0.376" and the matchfit bit isnā€™t as snug as the router table, the bottom of the dovetail is 0.4925 much wider

Iā€™ll run a test cut with first a single pass of the 1/4" bit and the double pass to depth with it and see if the width of those cuts change, then Iā€™ll run the matchfit again, I canā€™t figure out how I might be getting wobble in the matchfit bit in the spindle itā€™s a 1/2" shaft bit and was snugly in the spindle. I feel the problem has to be with the matchfit bit as the 1/4 couldnā€™t make the dovetail part at allā€¦

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How can the matchfit bit be an issue? I am assuming you use the same bit in the router table as well as the Altmill.
About the only thing left is that you have runout in the spindle or collet. On the assumption that you are using a 1/4" collet for the 1/4" bit, if the resulting slot is 1/4" then the spindle doesnā€™t have excessive runout. I would then take some straight bit with a 1/2" shaft, mount it in the 1/2" collet and run a test pass and measure it.

Make sure the 1/2" collet is clean on the inside. Donā€™t use tape to hold down your test pieces as there could be some sideways shifting.

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Jens Bingo!

I just finished up the tests then came back here and read your message. Got some interesting data, the relief cut was supposed to be 0.375 from the top of the material, measuring with my calipers itā€™s 0.388 so the Z Axis is a touch off (the tool pocket cut was supposed to be 0.38 and itā€™s at 0.4075) , the slot was 0.26" for a 0.25" bit so not bad

The I stuck the 1/2" Collet in and put in the matchfit dovetail bit, all seemed good, snugged it up and then spun the spindle up and boom, I can see a wobble in it. I pulled out the collet and cleaned it up, same, then I took a look at hte collet nut and it had a clump of oil in dust in it which I cleaned out, then I spun up the matchfit and it spun nice and straight, ran the sample dovetail slot, and boom itā€™s all like it outta be, mystery solved!

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