Precision-drilling wood edge

[Ecnerwal]

Stepper motors, gears, a controller box, and a computer. 'cept us old farts with the cables an' pulleys instead of gears, but even I'm considering some new parts. Nothin' to it...

[Morris Dovey]

The same program that I used to create the graphic is also used to control a CNC router. I put together the graphics generation as a way to do a reasonableness check of my CNC part programs.

The program controls stepper motors that move the spindle in x-, y-, and z-dimensions. The goal with this particular program was to be able to drill any size hole with any bit with same or smaller diameter with a maximum 0.001" error, the least amount of cut overlap, and the smallest possible number of "move" commands

- starting from the center of the hole (to avoid having center cut-outs flying around the shop.)

It was an interesting challenge. I had to go back and add logic to restrict depth of cut after snapping a 1/4" carbide bit. Now the program cuts "deep" holes in stages - and doesn't break bits.

If the routing is beeing done freehand, all that really matters is that the edge is clean - and there needn't be any concern that the hole won't be completely cleaned out.

There's a link to an early (and primitive) version of the CNC code at

You can download the text file DRILL.SBP for a look (unix text; set tabs to 3).

[Morris Dovey]

Unless you /really/ crave this year's Darwin Award, I'd suggest you not allow any loose metal anywhere near the whirly parts of a router!

It's ok to run a drill bit at < 3000 RPM through a bushing; but please don't do that try it with a router bit at a much higher RPM. It /will/ hurt you.

But I didn't say there wouldn't be any arithmatic (-8

[Duane Bozarth]

"Mike Rocket J. Squirrel Elliott" wrote: ...

...

All I can say is "plan ahead"... :( Drill pilot and go slow...after drilling if needed you can epoxy over any loose area on the inside and let cure. If similar to Soss, depending on the size, you may just epoxy it in place.

[CR]

Asian-sourced.

Maybe a 14mm end mill used for metal work in a horizontal or vertical milling machine? I have used them before in a router and drill press. They leave a flat bottom and have no trouble chewing a clean hole in wood or MDF.

CR

[John Hines]

You will be pleasantly surprised. A brad point bit has cutting spikes at the edges, so it makes a clean cut in wood.

The drawback is they (bradpoints) are only good in wood, or wood like materials. They don't cut metal.

[Mike Rocket J. Squirrel Elliot]

Duh. The only upside of this is it gives an interesting puzzle to solve, and only one chance to get it right!

[Duane Bozarth]

:)

Well, I think if you're careful the chip out won't be bad and whatever does happen can be repaired...

(I know, it's a pita when it isn't as neat as you'd like and, whether anybody else ever knows,

[Mike Rocket J. Squirrel Elliot]

Excellent idea! My favorite vendor for parts mechanical is McMaster-Carr

and they don't appear to have end mills with 1/4'' shanks -- only 3/8ths and larger (except for a few odd 3/16ths offerings). Any machinists reading this NG?

[Duane Bozarth]

It'll work in the drill as is, of course...you could have a machinist turn a shank--there's the excuse for that small bench top lathe you've being eyeing... :)

[Mike Rocket J. Squirrel Elliot]

I will perform a series of high-controlled scientific tests. Lab coats, clipboards, Coke-bottle bottom goggles. See how that puppy works.

[Duane Bozarth]

...

Should be no problem, I agree...

[Mike Rocket J. Squirrel Elliot]

Right -- I was thinking of chucking it into the plunge router, since that thing has pretty much all the parts required to A. prop the router shaft at right angles to the work piece, B. a means to moosh it into the work piece, and C. a thingy to stop the moosh action when the tool has delved deeply enough into the work piece.

[Duane Bozarth]

...I've not had too much success w/ the end mill in wood, personally so have pretty much abandoned...perhaps there are others more suited now...the high rpm of the router would worry me...you can, obviously, try it first, of course...

If, otoh, it does the job in a scrap piece, then seems easiest...

But, you really to tell significant other you simply must have that lathe in order to finish... :)

[Mike Rocket J. Squirrel Elliot]

Hm. You speak words of wisdom.

[CR]

Didn't think about the 14mm and your only having a 1/4" collet. Mine has a

1/2" collet but that wouldn't accept a 14mm either, another brilliant idea blown to hell.

CR

[Mike Rocket J. Squirrel Elliot]

Yeah -- what is that about the susceptibility of brilliant ideas to hell-bound explosions, anyway?