chamfering braces

[mac007]

Hi

I'm chamfering 20x10 spruce using 'the book' method of screwing the brace to a rebated fixture and freehand routing on a table against the top bearing.

It all seems a bit hazardous- the 1/2' router is a beast!

Anyone got a better way apart from hand planing?

thanks

mac

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[Taffy Evans]

Hi Mac007, that's an interesting way to do that job, never heard of it before. I prefer a tiny plane and a very sharp chisel for that task. I shape my braces after gluing them to the plates to get a feel of the response and flexibility. By the time I get my router out, fit the bit, secure the brace, do the routing, and put it all away, I will have the job done. Well not completely as that's the part of my build that involves fine tuning. I enjoy hand-working as much as I can. Having said that, I have dozens of jigs and aids that make machine tools easier and safer to use. Have you thought of fixing the router and moving the brace held in a suitable jig?
Not much help, sorry.
Taff

[mac007]

thanks Taffy,

Sorry my explanation isn't clear. The router is fixed to the table and the brace which is attached to a length of rebated timber is fed along the router bit with the top bearing providing depth guidance.
The shaved spruce length then is flipped over and

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the process repeated. This provides a nice even gable section which is glued in place and then scalloped with a chisel as required

[kiwigeo]

I usually cut a bevel on my braces with a 1/4" shaft 22-1/2 degree bevel cutter with bearing on top as per original post....Im using a 1/2" capable router but with a 1/4" chuck. Never had any issues......just do each cut in several passes chumping off a little with each pass. Also make up brace stock with plenty of extra at each end to allow for any bust out.

[mac007]

Thanks Martin

Do you use a fence or just freehand up to the bearing?

Do you find on say a first shallow pass it has a tendency to bite in?

thanks for the reply

[kiwigeo]

Definitely use the fence

[Dave M]

Using this technique like creating the bottom radius it is all bit of a faff but once set up it is very quick. A good reason to do a whole lot of braces in one go. After all we know there are going to be other guitars don't we!

[WJ Guitars]

See photos of router table to make chamfer braces.

Wayne

[TallDad71]

I’ve taken to laminating my braces with 3 ply and then shaping using small planes and chisels. I quite enjoy the process of shaping to be fair and wouldn’t enjoy the advantages that machining would give.

This is a rubbish answer I know.

If you have a bobbin sander that may be less vicious?!

[Trevor Gore]

Hi

I'm chamfering 20x10 spruce using 'the book' method of screwing the brace to a rebated fixture and freehand routing on a table against the top bearing.

It all seems a bit hazardous- the 1/2' router is a beast!

Anyone got a better way apart from hand planing?

thanks

mac

IMG_5081.jpeg

The screw holding the brace should be on the centre line of the brace and penetrate half the height of the brace (~10mm). I use two screws, one at each end, and pick up on the same screw holes when I flip the brace to rout the other side. The screws should end up no where near the cutter blades. My fixture is wider than it is tall, which helps with stability. As drawn, yours appears taller than it is wide. The lower part of the brace in the fixture (which becomes the top of the brace) is stabilised by being in contact with the router table and firm pressure from the bearing holds the spruce against the fixture. Always have the bearing pressed against the spruce or you will likely get chatter.

My fixture is made from a heavy lump of Tas oak, (any other dense hardwood will do). The extra mass stabilises things, and I feel pretty safe doing the cut in one pass, as per Fig. 7-6 in the Build book. If in doubt, make the fixture bigger! Think about the grain direction when you set the piece in the fixture and you should get quite a smooth cut. If you don't get a smooth enough finish for your liking (usually a function of the sharpness of the cutter), rout a little lighter and then finish off with a couple of strokes with a block plane, with the brace still in the fixture. Then flip the brace and repeat for the other side.

[Trevor Gore]

Double post, sorry.

[mac007]

thanks Trevor,

I got some chatter and that's what put me off.

I'm sure your method is OK-I'm going to try the featherboard support suggested earlier so the 20x10 is supported/constrained 3 sides and feed the spruce through progressively using each new piece as a push stick.

And not stand behind the infeed in case it kicks back but the featherboards should trap it OK

Many thanks

MK

[kiwigeo]

And not stand behind the infeed in case it kicks back but the featherboards should trap it OK

Many thanks

MK

If you're feeding the stock into the cutter in the right direction and you have a firm hold on the stock/jig you shouldn't be getting any bad kick back. I have a big black arrow marked on my router table showing correct direction of feed.

What size cutter are you using? 1/2" or 1/4" shank?

[mac007]

I was using a 1/4" with a collet reducer in a Makita 1/2" but seconds after I started the router this happened.
BTW The cutter was fully seated and tightened and the collet was also a 6.35 Carbitool ie a snug fit.

It became airborne and gave me quite a moment!

After the smoke cleared I vowed to not use a reducer and stumped for a 1/2" Carbitool.

I think maybe the 1/4" shaft and top heavy cutter got a little "off concentric" (revised) as it sped up and it bent and released!

Thanks for the input-I'm planning a bulk run this week with the featherboard set-up

Cheers

MK

[Trevor Gore]

Yikes!!!

I gave up using collet reducers many years ago, due to eccentricity issues. I never had an incident, but it always looked like one waiting to happen. I now only use routers where proper interchangeable collet sizes are available (primarily DeWalt (1/4", 6.00mm, 1/8") , Makita (1/4", 1/8"), Triton (1/2", 1/4", 6mm).

If you can, dear readers, please get rid of your reducers ASAP!

[Taffy Evans]

Hi, I had the same problem with the reducing bush in my Makita ½” router. I have converted it to an overhead pin router and only use the ½’’ shank bits. I suppose I could also use it to shape braces, but I enjoy the handwork. But I use it similarly to shape my kerfing strips as I do those in batches.

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Taff

[TallDad71]

I was using a 1/4" with a collet reducer in a Makita 1/2" but seconds after I started the router this happened.
BTW The cutter was fully seated and tightened and the collet was also a 6.35 Carbitool ie a snug fit.
IMG_5086.jpeg

It became airborne and gave me quite a moment!

After the smoke cleared I vowed to not use a reducer and stumped for a 1/2" Carbitool.

I think maybe the 1/4" shaft and top heavy cutter got a little "off concentric" (revised) as it sped up and it bent and released!

Thanks for the input-I'm planning a bulk run this week with the featherboard set-up

Cheers

MK

Jeesh, you really dodged a bullet there MK, congratulations.

I wonder whether the alignment has always been asymmetric and that was the cause of the chattering in the first place?

[mac007]

possibly

Also the router was a "give-away" from a local woodworker group and maybe it's a bit worn and not rotating perfectly true.