question about routers and flushcut bits

AntCaps

AntCaps

Joined
May 6, 2009
Messages
924
hey guys,
I was at my local hardware store yesterday and i say that they had these little routers on sale, it got me thinking. using a router with a flush cut bit (one of the bits withe the bearings on it) could i trim up the scale material to fit perfectly. it would be cutting 1/4" g10 now im sure it would be hard on the tooling but is it possible? have any of you done this? i know the immediate response is to use a bandsaw or a belt grinder but i have neither and the router is the cheapest option that also has other uses around my house.
 
I don't see why not. It won't be perfectly flush more than likely but close enough to hand sand. I've used a router and corner rounding bits to radius tomahawk scales evenly all the way around.
 
anything to make it easier lol iv been burning threw jigsaw blades than having to file or sand my scales to shape and it just takes forever. even if it got it within a 16th id be happy. I think im going to give it a shot i can get a router the bit and build a makeshift router table for under 200 canaidan.
 
In this particular case I believe a 1/4" radius.
 
Yes, I've done it and it works.

The trick is getting the guide bearing set to the right depth so it rides along the spine properly.
 
I have wanted to try this for a while. I often see inexpensive router tables with and without the router on craiglist.
 
I've watched G10 being routed to fit handles on youtube and figured I'd try it as well. Looked like a quick way to fit them.

I have a full size router table that I plan on using for handles but I'm in the process of building a smaller router table to cut jimping on blades and to clean up the inside of drilled holes for things like karambits. I'm using a 15"x15"x1/4" plate for the top, 2x4's that I cut down to 1 1/2"x1 1/2" pieces for the frame and 1/4" sheets for sides. I built it to match my portaband. Right now I'm just waiting on the electrical boxes to get here later this week so I can wire it up and get it finished.

The door in the rear is for changing bits and adjusting the bit height. The switch will be wired into an outlet to power the router and a magnetic lamp I'm gonna mount on it. Then I'm going to use a 1/4" x 1 1/2" x 15" flat bar that will be slotted on both ends for a fence. I'll drill and tap the top plate and use threaded knobs to allow for adjustment. I'll cut a horseshoe of different sizes on the front and back of the fence for the 1/8", 1/4" and 1/2" bits that I'll be using for it so I can be exact with the depth of cut.

Here is what I have done so far.

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It will work, as has been mentioned adjusting the bit to the right height so the bearing rides on the knife tang will be one challenge, and the scale will need to be a consistent thickness with parallel surfaces. You will probably need to build some jigs to use trim bits to trim knife scales safely and efficiently.

If you use the flush trim bit in a laminate trimmer (small router) you will have to deal with clamping the knife down to a surface, while leaving space below the knife for the bearing and retaining screw or nut to clear the surface. You need to be careful not to tip the router sideways while trimming, which may require blocking up one side of the router base with something the same height as the knife handle.

If you use a router table, you need to find a way to hold the knife safely while trimming, and providing a guard over the spinning bit is a good idea. A "start pin" will help with control when starting the cut.

Feed direction and wood grain direction matter with router bits. Cutting around a knife tang will require multiple changes in feed direction. Go the wrong direction and it is possible to tear out or splinter the wood. Long cuts on straight grain can be risky too, with long splinters coming off sometimes. Manufactured materials are usually more forgiving, and you can feed in the usual direction, against the rotation of the bit. Some plastics will melt rather than cut unless the tooling is sharp and the feed rate just right. Trimming would best be done one scale at a time, before gluing up, as the bearing on a flush trim bit is likely to be thicker than most knife tangs.
 
A router is a handy tool in the shop with lots of uses, but your material needs to be very close to the correct profile prior to trimming. I would use it as a "clean-up" pass only, once the rough shape is done, no more than 1/16" for free-hand passes against the pattern. Anything more will require a lot more horse power on 1/4" material to run properly. A 1/2" flush cut bit is most likely your best bet, good carbide flutes & remember to keep the bearing oiled or they will blow out under a load & destroy whatever is near them. Keep your fingers away from the cutter!

I use a 1/8" or 1/4" radius cutter for handles, depending on the thickness of material I have to work on. It's just a simple setup, but saves a lot of time & gives a nice edge to work with when sanding for a finish. A dull cutter will burn the edge as it runs, a sharp one will leave a nicely finished cut.
 
Thanks for all the input guys,
Im planning on using a router table of sorts i watched a video on youtube on how to make one easily. The router im looking at is 3/4 horse power it adjusts height so getting the right depth should be easy enough and id be buying both a 1/4" and 1/2" flush cut bit plus a round over.
 
actually i had a crazy idea... what if i chucked up a carbide cutting tool in the router for rough cutting the scales than swapped to the flush cut for the finishing pass. im aware this wouldn't be the safest thing in the world. Im just wondering if 3/4 horse would be enough to power a bit threw some 1/4" g10.
 
It will do it but it will be hard to control your cut.
 
I think I'm going to give it a shot. I'll keep it in the table I'll get the shortest bit I can find and only have it as high as I need it. I wish I could afford a decent bandsaw but I can't justify buying a tool I won't have other uses for.
 
I would say make a pattern to use for routing but if you had the tools to make a pattern easily you'd be just using them to profile your G10.

FWIW I don't even profile G10 in a saw or anything. I cut the rectangular size I need, pin it to the knife and grind it to shape with a 36 grit belt. It grinds faster than wood or micarta with almost no heat. It's not worth the time and blade damage to bandsaw in my opinion.
 
im totally aware that a belt grinder is a better option but as of now and for the near future at least i cant afford one. Thats why im looking for a cheaper tool with more uses at the moment.
 
I will just point out some things that have been left out of the conversation. If you cut G-10 with a router you will need carbide tooling.

Working G-10 creates fine glass dust and fibers. These will damage your lungs and get in your skin.

If you don't have a bandsaw or a grinder, it is unlikely you have a vacuum system for removing the dust created. G-10 dust MUST be vacuumed up as it is created. It is very bad to breathe, and gets on everything. It can make you itch, too. You MUST wear a good respirator after working it. Also, clean off your clothes and the counters around the work area to get up the very fine glass dust. Long sleeves and full length pants are a good idea when working any glass fiber material.

I don't recommend anyone without a full shop, proper respirator, and a good dust recovery system using G-10. I rarely use it myself unless there is nothing else that will work. Micarta is a better choice if you don't have the proper equipment.
 
I do it with jigs for standardized, waterjetted knife/tomahawk blanks. With one-off tangs, I use spacers to make sure that the bearing rides against the tang but the bit itself cuts the handle material.

https://www.youtube.com/watch?v=I5jUlg0lEBc&t=897s

I use flared tube rivets for several reasons, one of which is that doing so allows me to use machine screws and standoffs to bolt the slabs to the jig to shape on the router. The countersink lets the heads of the machine screws stay below the level of the material and slide across the router table top easily.
 
Most of the things I make use machine screws as handle fastness anyways so I'll be able to bolt them on and rout them. I'm aware of the dangers of G10 I cut concrete almost everyday of my life so I'm well aware of proper PPE and respirators.
 
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