milling slot question

Don't cut the slot full-width in one pass. Use an end mill smaller than the desired slot width. Start right down the middle of the slot, and take cuts running back and forth the length of the slot, going deeper by about 1/2 the diameter of the cutter each pass, until you break through the bottom. Then, offset the part a bit, and take one side up to the desired slot dimension. Then, offset the other way and do the other side. if the machine is tight, do these cuts in the climb-milling direction, where the feed is with the rotation of the cutting edge. This gives dramatically better finish in aluminum. (If the machine is loose, this cutting direction can cause the work to jump into the cut, so not a good idea.)

This is all MUCH easier with a CNC machine, of course.

Jon

Reply to
Jon Elson
Loading thread data ...

How do you get a 1 3/8 deep slot in a 1 x 1" piece of stock?

Jon

Reply to
Jon Elson

A dumont push broach will also work. Been there done it. Still use the jig for some slotting jobs.

Best Regards Tom.

Reply to
Howard Beal

My Clausing 8525 which is half the size of a Bridgeport can cut a full depth (1-3/8") slot with a 4" slitting saw held in the cheapest of the MSC arbors I referenced, though I have to make multiple passes because the 1/2" collet doesn't transmit much torque. The example I have close at hand is a home made 3/4" steel boring bar slit 1-1/8" deep into the end, to tighten onto the bit.

It should be easier in aluminum with a new saw instead of the used ones I cut steel with.

formatting link

Makita panel saw blades are cheaper and somewhat larger:

formatting link

-jsw

Reply to
Jim Wilkins

It will be done on the CNC with a small bit. For the old manual mill there was no bit available smaller than 3/16 long enough to do the job.

Reply to
clare

Deep if measured from the end. Through if measured from the side.

More accurately, 1 3/8" long

Reply to
clare

Pretty difficuld to do with a shaper to get a clean cut at the base of the cut (end of the slot) unless cutting across the stock (1 inch cut) and then to cut 3/16" wide and 1 3/6" deep would be some fun - -

- -

Reply to
clare

That is done by the drilled "stop hole" - or by the end mill finishing the slot - 3/16" slot with 3/32 radius.

Reply to
clare

The MSC #: 73324048 would do the job IF I had an arbor - and it is almost $90 plus shipping and brokerage - make that over $125 (Canadian) just for the cutter. - plus the cost of the arbor.

The cheapest arbor -MSC #: 08271058 adds another $45 plus shipping and brokerage. - and then I need a mill that will take the 1/2" shank. (which I don't have)

No worries - it's all being done on the CNC machine next week - or whenever the machine is not in use.

Reply to
clare

snipped-for-privacy@snyder.on.ca fired this volley in news: snipped-for-privacy@4ax.com:

It's pretty difficult to get a clean, well-matched cut when you have to flip the work and cut a 'half-slot' on each side, too.

If you don't have the capability to cut a slot that deep, likely you don't have the tools or experience to get the work perfectly-registered on the flip, either.

Besides, cutting two 'features' on opposite sides of a piece of stock so they meet in the middle is NOT "milling a slot". It's exactly what I just described in the prior sentence.

Rule of thumb -- if you don't have the tools or ability, then farm it out to someone who does!

I'm not an 'experimental' pilot, but I am a pilot. I know somthing about how planes are put together (yeah, even the structural parts, having helped A&Ps over many hundreds of hours, just so I'd learn something). I seriously doubt that a mating feature like that need be as accurate as you're demanding in order to be robust and safe. If play is problem, mill the parts for a too-tight fit, and adjust for perfection with hand tools.

Lloyd

Reply to
Lloyd E. Sponenburgh

If you want, I have a program online that will generate the G-code for this. See :

formatting link

And get the "milling a rectangular pocket" program. I have some more specific ones for slots with round ends that I have not published.

Jon

Reply to
Jon Elson

Kinda makes it a thru-slot, dunnit?

Reply to
Larry Jaques

Yes it does - picky picky picky --

Reply to
clare

Not that it is particularly relevant in this application, my favorite tool for cutting aluminium is my cheap ass band saw ("Simple Simon" brand from Wilson Brass and Aluminium Foundry in Toronto) with a 4TPI wood blade. This saw doesn't even come with a rip fence but modifications have been made.

Reply to
geraldrmiller

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.