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Re: ROUTER BITS 1/2" vs 1/4"
By:Charles Cooper
Date: 11/5/1999, 1:05 pm
In Response To: Re: ROUTER BITS 1/2" vs 1/4" (Jack Sanderson)

> On this same topic. I have a craftsman 1-1/2hp router that I want to mount
> in a router table to do, among other things, cove and bead strips and
> raised panel doors for kitchen cabinets.

> The guy at the local woodworkers warehouse was selling me hard that I want
> a router with more horse power and 1/2 bits vs 1/4" shanks for the
> door bits. Does anyone have an opinion on this. The raised pannel and b&C
> bits are a long term (hopefully lifetime) investments and I am trying to
> do some cost benefit thinking.

If you are going to be buying a router, get one with the 1/2" collet. You can always get an adapter to use 1/4" shank bits if you need to. Most 1/2" routers are shipped with an adapter anyway.

> Some assumptions I'm making

> 1. 1/2 bits cut smoother than 1/4" because they are stiffer and have
> more mass. I assume that this is more important on hardword and cuts that
> take out more material like the raised panel cutters than cutting a cove
> in 1/4" soft cedar strip.

It depends on the quality of the bit. A cheap 1/2" bit will run rougher than an expensive 1/4" bit.

I once purchased a large bit (2.5 inch raised panel cutter)at a local discount tool house because my regular supplier was closed on Saturday afternoon. Went home, cleaned the gunk off the it, inserted it into the router, set the speed control to the correct speed and turned it on. The rattle and chatter of the unbalanced bit in the collet scared me to death. I immediately hit the deck and punched the OFF button on the way down. I set the speed control to 0 and restarted the router. Carefully bringing the speed up caused chatter at about 20% of the required cutting speed. Unfortunately the distributor won't take the bit back, and I now have a really sharp plumb bob weight... On Monday I went to my regular shop and purchased a good bit (at twice the price) and it runs fine. You get what you pay for.

The larger bits do have more mass, but it doesn't have much real effect on the cutting. If you are experiencing chatter or the wood is burning with a 1/4" bit, it's not due to lack of mass. It's more likely due to a low quality or dull bit or the feed rate into the wood is too fast.

The mass does become an issue when you are using really large bits as the start up torque of a large bit can cause a bit or wear on the bearings. This is only really a problem in a production environment, but see my last comment re solving this.

> 2. 1/2 bits need a 2-3 hp moter to drive them effectivly. Conversly I
> assume I won't find a router that accepts 1/2" bits that doesn't have
> a bigger motor.

Yup.

> 3. The woodworking warehouse guy was telling me that you can get these
> bits in 1/4" but then relayed horror stories of bits breaking off
> when over loaded. Part of me felt it was a sell job and part of me
> couldn't help imagining grizzley scenes of what would happen if one of
> these bits broke off at the kind of RPM they go at....flying metal chasing
> me around the shop ahhhhhhhh!!!

Once again, if you get into that sort of thing, you're not really using the tool correctly. Of course it's too late once the bit breaks...

> Things I'm confused about

> 1. Is a router with a plunge base easier or harder to mount in a router
> table. I think I have heard arguments for both sides (i.e. a plunge is
> easier to adjust vs you have to take off the plunge attachment to mount on
> a router table).

I have a plunge base router in a table. It works great. It adjusts easily, and have not had to "take off the plunge attachment" to mount it. Most plunge routers have some sort of handle (really a knob on a long shaft) that is used to set the plunge level. You can use this handle when the router is mounted under the table or replace it (as I did) with a slightly larger handle that is easier to find/use when the router is mounted upside down. I don't have to change back to the standard handle when I use the router out of the table...

> 2. I have heard that a speed control is helpful. In what situations do you
> want to slow down a bit.

If you are using a C&B bit set you don't need it. These bits are fairly small in diameter and can be run at full speed in the router. Larger bits such as the ones you will be using for the kitchen cabinets need to be slowed down. What you have to remember is that the larger bits have a faster "rim speed". That is, the tip of the bit (being farther away fom the centre of the bit) is travelling a greater "distance" with each bit revolution. In order to "keep up" with the rest of the bit, it effectively travels faster...

These big bits (anything over 2" diameter) are designed to be run at lower speeds. This keeps the stresses at the tips down and reduces chances of the bit (or you) being damaged. Any inbalance in the bit will be enhanced by the speed and can cause problems.

Think back to those spinning platforms that are in many playgrounds. As you move from the centre of the platform, the forces get stronger and the likelyhood of you being thrown from the platform increases. Slowing the bit down is a really good idea, and is often mentioned as a "requirement" on the bit package.

> Thanks for the info. My tendency with tool purchases is to buy things
> better that what I need vs things that will just get by for this job. In
> the long term I have been glad I spent the money but it is hard to shell
> out this kind of dough.

You might want to look at a router that has an electronic speed control built right in, it only adds a few dollars, and saves you buying an extra speed control later. Routers with these usually have a "soft start" feature that tends to reduce wear and tear on the bearings when large bits.

I hope this helps.

> Regards,

> Jack

Messages In This Thread

ROUTER BITS
DAN MOSLANDER -- 11/5/1999, 12:28 am
Re: ROUTER BITS
Rehd -- 11/5/1999, 9:46 pm
Re: ROUTER BITS
Bart Castleberry -- 11/5/1999, 8:32 pm
Another source
Mike Scarborough -- 11/5/1999, 2:34 pm
Re: ROUTER BITS
Charles Cooper -- 11/5/1999, 1:29 pm
Re: ROUTER BITS 1/2" vs 1/4"
Jack Sanderson -- 11/5/1999, 9:32 am
Re: ROUTER BITS 1/2" vs 1/4"
Charles Cooper -- 11/5/1999, 1:05 pm
Re: ROUTER BITS 1/2" vs 1/4"
Tom Kurth -- 11/5/1999, 8:53 pm
Re: ROUTER BITS
Greg Hicks -- 11/5/1999, 8:52 am
Re: ROUTER BITS
Dave Houser -- 11/5/1999, 1:40 am
Re: ROUTER BITS
Tig (and Tink) -- 11/6/1999, 3:11 am