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I have always bandsawed the greatest part of the overhang and then sanded the sides until the top and the back were flush with the sides.
It is getting rather tedious and I want to try using a flush cut router bit, but I'm scared I might chip out a piece of the top or back.
Does anyone have any suggestions for a flush cut bit.
Does anyone have any technique tips?
Thanks

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Formerly know as Mandodiddle.

Any flush cut bit should be fine. Try to cut it close on the bandsaw or other method if you have excessive overhang.

If you use the SM binding cutter bit it comes with a flush cut bearing. Still follow the same rules regarding direction:



Brad


Sent from my iPhone using Tapatalk Pro

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Insta - https://www.instagram.com/cbcguitars/
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I use a regular binding bit, and cut a .06 deep channel about 3/32 in height. This is more than flush, and means when you’re faring the sides, you don’t have to deal with sanding end grain. Any cut that is less height than your binding, and less depth than your binding. It also means that when you come to route your channels, the heavy lifting is done and the bits have to take off just the tiniest bit, and they last a long time. A Grumpy trick.

You do need to use climb cuts in certain sections. If you go to StewMac’s tips and tricks page or whatever it is, or maybe even on the binding bit page, you’ll find a diagram showing where to use climb cuts…

Yup, that’s the diagram, lol…

Bill I would print out the diagram (StewMac has their Dread kit instructions available free for download) that Brad (thanks man) posted and tape it on the wall above my bench when I used a Laminate trimmer with a flush cut bit to do climb cuts.

I have a memory of someone not using climb cuts on the OLF and posting that they experienced a large chunk of the top being ripped off and they had to retop the instrument. See that once and you always remember to do climb cuts.

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Ann Arbor Guitars

Since I do all overhang and binding routes with the body in my cradle I took a Sharpie and just marked the cut directions on the cradle.

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Steve Smith
"Music is what feelings sound like"

One of my favorite woods (Osage Orange) is a bit chippy when it meets the router. In addition to always cutting on the downslope, I started using this bit: bearing-guided downcut spiral. It’s a little slower than a normal flush cut bit, but it doesn’t throw splinters.

That's the bit to use, alright. Bob mentioned it before I got here.

I fit the top and back and rout them to the final shape with the rim in the mold before gluing them on. Then I do the final 'free' plate tuning. I found that in some cases even a bit of overhang could change things. Also, with the top and back trimmed to shape first it's relatively easy to get things lined up when I'm gluing them on. I use spool clamps, so the rim is no longer in the mold at that point, and it's easy to end up with some twist if you don't have some way to align things. With the plates to the exact shape all (...'all'...) you have to do is line them both up all the way around to end up with everything square.

What diameter of downcut flush bearing bit?
It seems like the larger the diameter the less likely it is to create tearout?

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Formerly know as Mandodiddle.

The one I displayed was 1/4” diameter. I get much less tearout with that than with a 1/2” bit. The part of the bit moving away from the inside of the cut is much smaller with the smaller bit. Also, be cognizant of the cutting tip speed. At the same rotational velocity, the tip of the larger bit is moving much faster.

I use a Whiteside 1/4” down-cut spiral flush-cut bit

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Steve Smith
"Music is what feelings sound like"

"shear angled" flutes work fairly well and are a bit cheaper than spiral bits, and can be touched up with a small diamond hone rather than needing to be sent out:
https://www.woodline.com/products/1-2-s ... with-shear
Many other makers also make this type of bit.

I seem to recall Mario using one of those drywall bits used for cutting outlets for this?

He was using Zip bits although I forget which one. I tried it once and it worked but I’m more comfortable with a down cut flush trim router bit.

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Steve Smith
"Music is what feelings sound like"