so question ?

I need to route a 1/8" wide x 1/4 " deep "L" on a block of alum bar stock
that's 1-1/8" x 2-3/8" x 3/4"...........routing only one of the 1-1/8 x 2-3/8 sides

Plan on doing it with a rotary tool like a dremel etc...

What's the best bit to use ? My experience with alum and grinding wheels
is that they quickly bind up with material.

Anyone have any input ? on the kind of bit etc? or other ideas on what to use

DUB ? any ideas ?

 

Use cutting tools not grinding will probably give you cleaner lines. Slow speeds,
let the cutter do the work. Check the teeth often for galling. That's when the soft
aluminum fills the space between the teeth and reduces the efficency of the cutting action.

If you have access to a table saw, mill the slot and then cut to final dimension.
That gives you sufficent stock to effectively handle and control the piece.

If you do use a dremel, set it up stationary and using a guide, move the piece,
instead of securing the piece and moving the dremel. Taking multiple passes to
achieve final depth will better assure control and final results to the piece.
(Not to mention wear and tear on the dremel tool and cutter, itself.)

Test your setup on scraps first, then your real work.
Use carbide tooling and it's basically just a really hard wood, as far as procedures.

PM me if you want some added input.

Hope this helps, Ern

 

MadHat's got it Sprock. Check some on line catalogs for die grinder bits that are designed for alum. We use them in handheld pnumatic diegrinders to trim and fit Landing gear doors and such.

 

yeah setting it up stationary is a gimme with a fence to slide it on - good idea milling
in a length alright rather than short pieces

So a carbide dremel bit ?

Something like this eh ?

Suppose this approach would mean incremental passes too ?
Since I don't think a dremel has enough torque to get a 1/4 inch
of material removed cleanly in one shot !

I have a table saw but not a carbide tipped blade for metal
I believe it's carbide tipped for wood maybe ! ??? make any difference ???

apologies brains doing overtime on this one - not a healthy situation
where's the Screech

 

Actually, not a rasp. a cutter.

Have you ever used a router and/or table set-up?

Mount the dremel at 90 degrees, poking through a 1/4" hard-board table. Mount a staight-edge fence at the correct distance. Facing with the fence BEHIND the cutter, feed from right to left. Use a push stick! It sucks when you carve a 1/8" slot in the palm of your hand. I would not recommend taking more than a 1/16" on a pass. Listen/feel that first pass, if it sounds/feels like too big a load, back it off.

If it's a standard alternating bevel, or skip-tooth carbide blade on your table saw, it will work fine. I recommend using an older/used blade, you WILL ruin it for fine-work in wood, as soon as the aluminum touches it. I trim multi-million dollar commercial buildings, so I have a high standard, though. (When my trim blades start chipping out on hardwoods, I'll hold one back from the sharpener, specifically for aluminum).

Cutting aluminum depnds on a FIRM grip with hold-downs or push-blocks and a SLOW feed-speed. Let the blade do it's job. Especially, when it's not a through-cut. You need to leave time for chips to clear.

Take several passes, increasing your depth each time. If precision is required, start with a test-piece and use it to measure/adjust the final pass. If it's really precise, make/use several, in case your final adjustment is too deep and you have to back off. You'll still have one to confirm/verify final set-up.

Hope this helps, Ern

 

Ern - yo the man - I have a decent sears metal router table - gonna give that a
shot

thx

 

You'll probably find the 1/8" dado listed with laminate router bits. If all you can find
is HSS they'll do, for no more than you've got to do. Do the groove first and then cut
to length. Easier to handle and can trim the start and exit of the stock. Those are the
areas, most prone to machining-error. Remember right to left! You might even add a
second straight-edge on the outside, to further reduce the possibility of chatter.

Also, re-run at each depth setting, to ensure consistancy/full depth, due to it wanting to 'float'.

Ps, the test pieces don't need to be run completely through, just enough to sample depth of cut.

Ern

 

Gotcha thx - no worries you'll see the finished product with the spools tapped in the
side

 

A grinder or wheel type cutter won't make the intersection of the two cuts unless you over run the cuts.

There are some non-ferrous dremel wheels that may work.

 

Oops, Never noticed the "L", specification. Yupper, if you use a table saw, it'll make
a 'T' or "+". The only way is to do stop-dado's with a dado router bit. See previous
router table comments. only add stops, to the fence, to control the length of the plows.

This can be an advanced/complicated procedure, if you want some face
time, PM me and I'll drop a dime on you and talk you through the issues
involved.

Ern