NOT a whizzing contest

[Bill]

Gents (and ladies, too) I have had the terribly brilliant and incredibly original idea of laying a router on its side in a table to cut mortices. This was brought on by a lack of a dedicated mortising machine, the fact that Woodcraft will not let me borrow theirs (no one else I know owns one) and a healthy respect for a dollar that will not let me buy top-end equipment for isolated or even single uses.

I found a couple sets of plans already and have made the adjustments to match the available stock and even cut the wood. I'm good to go on that score.

What I need now is the opinion of others as to the sizes and styles and manufacturers of bits for mortising with a horizontal router. The router in question is a single speed HF 2.5hp - 1/2" collet machine that I bought too quickly (I was ticked at Woodcraft for advertising the PC 7518 on sale but not having even one I could hold to get a sense of it. Dummy me, I wasn't sceptical enough. I just assumed that any router with that much hp would have some way of varying the speed. [Note to self: Bill, READ the steenkin' box!] Nope. Not this one.) clocking in at a claimed 23,000 rpm. WAAAY too fast for the raised panel bits I had in mind for it. WAAAY too fast.

(C=pi x D)x 23,000 x 60 / 5,280 = suicide

... it is going to become my official mortise & tenon router. But I am in desperate need of a clue.

What I THINK I need is a straight cut up-spiral bit (to pull the wood toward the router fence) that comes on a 1/2" shank in a few sizes (1/4,

5/16, 3/8, 7/16, 1/2) with the greatest depth of cut I can buy through normal channels. Probably carbide inserts or brazed carbide faced.

But then, I THOUGHT I needed that HF router, too.

Sign me:

Clueless in Detroit.

[Morris Dovey]

| What I need now is the opinion of others as to the sizes and styles | and manufacturers of bits for mortising with a horizontal router. | The router in question is a single speed HF 2.5hp - 1/2" collet | machine that I bought too quickly (I was ticked at Woodcraft for | advertising the PC 7518 on sale but not having even one I could | hold to get a sense of it. Dummy me, I wasn't sceptical enough. I | just assumed that any router with that much hp would have some way | of varying the speed. [Note to self: | Bill, READ the steenkin' box!] Nope. Not this one.) clocking in at a | claimed 23,000 rpm. WAAAY too fast for the raised panel bits I had | in mind for it. WAAAY too fast.

I don't think you did as badly as you think. HF also sells a router speed control that /may/ work with that router - I bought a pair of 'em on sale at $20 each and mine work with the routers I bought 'em for. Try the speed control out with your router at HF before you buy it.

| What I THINK I need is a straight cut up-spiral bit (to pull the | wood toward the router fence) that comes on a 1/2" shank in a few | sizes (1/4, 5/16, 3/8, 7/16, 1/2) with the greatest depth of cut I | can buy through normal channels. Probably carbide inserts or brazed | carbide faced.

Check prices on solid carbide end mills. I favor 3-fluted end mills from KBC Tools (because they're sharp, they hold up well, and they're less expensive than router bts) - which might be of interest to you because KBC's primary location is in the Detroit area. End mill shanks are normally the same diameter as the cutting edges, so you may need to shell out for router bits for sizes that don't match your collets.

The spiral up-cut is the bit you're after.

-- Morris Dovey DeSoto Solar DeSoto, Iowa USA

[Earl Creel]

(SNIP)

clearance angle do you use? Can you provide a link to the specific endmills or a stock number of a KBC Tool endmill you find works well? Earl Creel

[alexy]

Make sure to express D in feet rather than inches so you stay subsonic.

[Bill]

Good suggestion, Morris. I have a Production Tool within walking distance. I probably have one of their catalogs around. A couple miles further away is a J & L Industrial. And I KNOW I have their catalog!

Bill

[Bill]

Like this?

with a shallower spiral? This one is meant for aluminum ... but then, I really don't expect to find an end mill specced for wood. It seems like the standard lead angle is about 15 degrees but I'm too long from the trade to remember for certain.

Also, what sort of chip load do you aim for?

I may have to wander up to Production or J & L to bend the ear of the counterman.

Bill

[Morris Dovey]

| On Fri, 20 Oct 2006 23:17:37 -0500, Morris Dovey wrote: | || The spiral up-cut is the bit you're after. | | Like this? |

usually look for plain-shanked bits. That bit would probably cut well; but I'd worry about the effects of inbalance on my bearings at wood-routing spindle speeds.

| Or with a shallower spiral? This one is meant for aluminum ... but | then, I really don't expect to find an end mill specced for wood. | It seems like the standard lead angle is about 15 degrees but I'm | too long from the trade to remember for certain.

I would suspect that the high-angle aluminum bits might clear chips a little faster at the cost of increased tear-out at the top of the cut. I doubt they're worth the extra cost unless you're cutting aluminum. Too much heat when routing is a signal to increase feed rate, not to buy more expensive bits...

| Also, what sort of chip load do you aim for?

I haven't done chip load calculations. Most of my routing has been in wood; and there's so much variation in hardness/density that I tend to set feed and spindle speeds by listening to the bit and looking at the cut. My usual starting point is 14k RPM and 1.5 in/sec horizontal with

3/4 in/sec plunge feeds with a 3-flute center-cutting end mill. With a 2-flute end mill I usually start out at 18-24k RPM and same feeds.

-- Morris Dovey DeSoto Solar DeSoto, Iowa USA

[Prometheus]

Yeah, hard to forget a catalog that takes up a whole shelf by itself. :)

[Bill]

Kind of like the IRS tax codes ... and just about as expensive. However, with J & L you get to keep the tool. ;-)

(That, by the way, was my justification for buying the tools needed to hand-build some needed cabinets for our house. "Cost about the same but keep the tools".

It's also how I justify most of my 'working on the car' tools.)

Bill