Is this too much for an edge trimming/flush cutter?

[Simon Magennis]

I am trying to make friends with my routers. I have practically no experience using them. I have flush cutter and want to use to to trim the edges on my latest guitar. However the way I have built to date end up with 1 cm to 2cm (1/2" +/-) sticking out at the end. Is this something a router can tackle or is the risk of a big chunk getting ripped out too high? Here is the potential victim. Thanks.

[Bob Gramann]

That looks familiar. I often have big overhangs. Your success depends on you and your router bit. First make sure that the top and back are securely glued everywhere. Any place one of the plates is loose invites tearout. A router bit with some down slant on the cutting edge helps a lot. Always cut from the widest part of the body to the narrow. (Think about the direction of the cutting edge against the grain. You don't want the cutte to be grabbing a grain line that goes into the guitar.) When I have a wide ledge area, I sometimes work it down with several shallow passes of the router. Since you're just getting familiar with the router, it is probably reasonable to pause here and glue up some mockups with scrap wood to practice on and get a feeling for how the router works and cuts. That will take a lot less time than crafting a new top or back.

Even a 2 mm ledge is an invitation for router tearout if you give the router a chance to grab the grain.

[Chuck Tweedy]

You have much less chance of the router ripping out a big splinter if you use a small diameter tool.
A long time ago Mario Proulx posted a method of trimming overhang using Roto-Zip bits - the type used to cut holes in drywall. THIS. I've not used these, but...
That inspired me to use an edge-laminate trimming bit I already had - and still use for this operation. Even though it rubs against the side, it does not leave a mark that is not removed in the normal course of binding.

[Simon Magennis]

Thanks guys. Just the info I needed.

[Bob Gramann]

I saw Mario's video and tried it. Then, I went back to my slant-edged bit. I get them here:
http://www.mlcswoodworking.com/shopsite ... flush.html
Look about halfway down the page.

Every now and then, I touch up the edge with a diamond hone. When things get chippy, I replace the bit. I run the router at low speed when I trim the plates.

[David King]

I'd be climb cutting if that were my guitar and I'd also trim 90% of that overhang off any way I could think of besides a router. A luthier's knife probably or a very sharp rasp maybe.

[Mark Swanson]

If you have a lot to trim off it helps if you do it in several passes, there is no need to try and get all the way flush with the sides at once...easy does it, trim a little at a time.

[Simon Magennis]

Just some info. In the end I just grabbed a chisel and timed if off as if using a knife.

Then I ran it though my new "binding jig" build using the gore and gilet plans but not as pretty and precise. I have a Bosh "colt" (UK version but same thing) and built the "cradle" for the jig around that. The bosch depth adjustment is rubbish hence the question on the other thread regarding the router used in that jig (Hitachi). My "cradle" has no depth adjustment - I have to seat the bit at the required depth. I see why people have one router for each job. Not having to adjust anything certainly has it attractions.

End result was the cleanest binding channels I have ever had. I didn't do anything fancy like mark with a knife before hand or give it a quite shellac coat. Happy trooper. Maybe I will finally get friendly with routers. If only they weren't so loud.

[Clay Schaeffer]

"Maybe I will finally get friendly with routers"

Please remember, tools are not your friends. When you're not looking they can and will bite you. Or rather, you will bite yourself with them. One of the most common mistakes with routers is bottoming out the bit in the collet, which won't allow it to tighten the bit properly. When the bit slips all kinds of satanic imprecations are released.

[Todd Stock]

Trim overhang to no more than 1/2 the diameter of the bit, and use climb cuts. If the router is well controlled, there's not as much chance of a grab.

[Craig Bumgarner]

Probably too late to help the OP, but for cutting plates flush with the sides, I use a Dremel tool with a Stewmac (or Veritas) router base, a 1/8" downcut router bit and the Stewmac edge guide (Item # 4324) . With this setup, it doesn't matter how wide the edge is, the bit is acting more like a saw than a trim bit. Works great, been using it for years.

BTW, the same Stewmac edge guide will fit the Veritas router base which is a much better base. The Veritas has holes drilled and tapped in the right place for the edge guide, but the screws are metric, slightly larger, requires reaming the holes in the guide and new screws of course. The Veritas base is a little wider which can be a problem from trimming tops and backs with a lot of arch and recurve like on an archtop, but for flat or spherical plates, it works great.

[Stephen Neal Saqui]

For future reference:

I have a router permanently mounted under my workbench for this purpose (and others)....but it does really speed things up to begin the habit of trimming the top and back closer to size before glue up.

If you put a good sized scrap sheet of veneer on your bandsaw, make a cut, say 6" in, and clamp the sheet in place then you can saw the top and back almost down to size without any rip-out...a nice clean cut. I keep the veneer next to the bandsaw and use it frequently. It's especially useful for doing other delicate work on the bandsaw as well.

[Bryan Bear]

A word of caution on Stephens bandsaw suggestion above. Note he said trimming the back ans side closer to size BEFORE GLUE UP. I once tried to trim a back a little closer on a closed box. I knew it was a bad idea and totally ignored that little voice telling me not to. Naturally, my close eye on the cut kept me from noticing the that the top of the blade was closer to the edge of the box than the bottom where the cut was happening. I dug right into the side with the side of the blade.

[Stephen Neal Saqui]

Thanks Bryan...good to be clear!!

[Bob Howell]

For future reference:

I have a router permanently mounted under my workbench for this purpose (and others)....but it does really speed things up to begin the habit of trimming the top and back closer to size before glue up.

If you put a good sized scrap sheet of veneer on your bandsaw, make a cut, say 6" in, and clamp the sheet in place then you can saw the top and back almost down to size without any rip-out...a nice clean cut. I keep the veneer next to the bandsaw and use it frequently. It's especially useful for doing other delicate work on the bandsaw as well.

I'm looking for ways to cut thin wood on my band saw and found this comment. I don't see how the veneer helps. The finest blade I have is 6TPI. Can I expect good results ripping 1/8 and 1/4" wood? Its rosewood so I want to avoid the waste of the table saw.

Does the veneer help here.

[Jason Rodgers]

If I'm not mistaken, Stephen is describing a zero-clearance "insert" (in this case, overlay) for the bandsaw to avoid jagged, splintered edges on the down side of the cut.

[David King]

Bob, I have great results using one of the thinner re-sawing blades that's a 3-4 tooth and cuts a .032" kerf.
I order them here: http://www.spectrumsupply.com/kerfmaster-2.aspx
Select the 5/8" x .016" blade stock. I do recommend making a zero clearance insert for that or any blade. These blade seem to gum up quickly and they have to be kept clean to cut at their best but you will hardly need to sand the cut surface most of the time.

[Bob Howell]

I'm using a nylon zero clearance insert. I'll add the veneer. I just got 6 blades from them and a 3/8"x6 tpi x .025 seems to be the best choice.

I also got the 5/8"x .016 you mention. They have finer blades but I did not plan ahead and get, say a 12 tpi x3/8".

I think its time to try out a few of these suggestions and see what works. The old rule of thumb of 3 teeth in the wood is nice but not an absolute.

[Arnt Rian]

This is an old thread, and the OP might not see this but...

I use a 1/4" downcut piloted bit, which seems pretty safe, and the cut is very clean. I prefer to have a much smaller overhang than the picture shows, to cut down that much wood I would use a series of passes. It is a good idea to not extend the bit more than necessary if your router rides on top of the plates, as the bit will cut at an angle relative to the dome of the plates. The longer the bit, the the farther from the sides it will cut. I use a flush cutting bit in my binding jig to make the final pass, as it cuts at an axis that is parallell to the sides, so the plates will be cut very neatly to the profile of the sides.

[Todd Stock]

Try this:

- After the back and top are fitted, mark the plates with the body edge location
- Trim to 1/16"-1/8" outside that line
- Close the box using a top caul (protects edge from clamp and go-bar marks)
- Rout with flush trim bit

I don't know of any reason to leave 3/8" or 1/2" or whatever of excess material, given we have to fit the plates and control alignment...