GOOD angle aluminum? - RC-Monster Forums

BrianG · **GOOD angle aluminum? -** 10.12.2006, 12:44 AM

Where can I get ~5mm thick angle 6061-T6 aluminum stock for making a motor mount?

I got this from Onlinemetals.com, but it's not a perfect 90 degree angle. I measure it at 89.549 degrees. That doesn't sound really bad but you can actually see that it is off, which wears the spur unevenly (and it IS obvious). I used 0.05mm thick washers as a spacer on one end to compensate in my BL Revo, but I'd rather get stuff that's what it is supposed to be.

MetalMan · 10.12.2006, 01:11 AM

How about this one?:
http://cgi.ebay.com/2-X-2-X-12-ALUMI...em190035691310
It's 1/4" thick instead of 5mm, but that means it's about 1mm thicker than what you want. From what I see, the only problem is the shipping cost.

Come to think of it, I think I got my 2" x 2" x 1/4" aluminum angle from Online Metals, and it does appear that it's not quite 90 deg. However, I haven't measured, so I'm only going off of looks.

BrianG · 10.12.2006, 01:22 AM

Well, that would work (and actually not a bad price too), except I need about 3-3.25" walls. I guess I should have mentioned that. :dft001: It's for my Hyper8 buggy and I want to mount the motor over the rear brace, so it needs to be high. I plan on securing the face of the mount to the holes where the stock brake would go and then also on the bottom of the "L". Maybe even support the other end of the motor too.

Actually, I didn't actually measure the angle, I used a square and measured the gap at one end and then calculated the angle. Same thing I guess. That metal from online metals is said to be meant for structural applications, so I guess it's not terribly important if the angle is ~1/2 a degree off.

Maybe I'll simply ask Mike to machine a mount for me instead. I'll probably need someone to at least mill out the slots to adjust the gear mesh.

monel_funkawitz · 06:52 AM

Its aluminum. For the love of god, bend it to a 90. :018:

None of the angle I've ever bought was perfect and required a dash of Cresent wrench and a little bit of clamp for flavor. Only 90 angle I have that is perfect is stuff I machined out of billet.

If you want perfect, 100% pinion mesh, you gotta shim.

<----RC truck/tractor puller

JThiessen · 10.12.2006, 11:24 AM

I'll second the last post. You will never find a piece of stock that is perfect, no matter how thin or thick it is. You either have to machine it, or shim it.

Procharged5.0 · 10.12.2006, 11:55 AM

Extrusions are never perfect. they will require machining.

See: www.mcmaster.com for material supply.

BrianG · 10.12.2006, 04:06 PM

I realize I could bend it, but I doubt I could do so with the accuracy I want. So, I guess that leaves me with either the use of shims or milling the whole thing. Or, I suppose I could try to file down the necessary section...

monel_funkawitz · 10.12.2006, 08:54 PM

If you have enough patience, you will get it.

Aluminum is some proingy stuff anyway. If you get 100% mesh, it will change under heavy load anyway.

If it makes you feel better, I have a pulling tractor that I can slip a sheet of paper under half a pinion tooth. Its that far out of whack. If I go for more mesh, it turns into a gear muncher.

BrianG · 10.12.2006, 11:17 PM

Yeah, I've messed up a spur or two because of the "give" in the aluminum mount. I'm assuming the mount flexes on jumps due to the weight of the motor hanging there throwing off the mesh. For the buggy, I plan to re-inforce it by securing the mount to the chassis and also screwing the face to the diff holders (where the brake would go), and then support the back of the motor using the scheme glassdoctor uses.

I just figured the angle would be more accurate, even though it's extruded. You'd think there would be a way for the manufacturer to compensate if they knew it was going to be off. I still think the inaccuracy is at least party due because the application it was intended for doesn't need it.

On a somewhat related note; are there any "GOOD 3mm taps"? I got a drill and 3mm tap at my LHS and have broken both in trying to tap screw holes in 10mm thick 6061 (the spacer for my battery trays). Lowe's has a Ti coated set, but it's a big (and expensive) set and all I want is 3mm taps. I ordered some plastic stock so I can just drill smaller holes and have the 3mm screws self-tap.

MetalMan · 10.13.2006, 12:18 AM

Check out http://www.mcmaster.com for all of your tap and drill bit needs!

I've been using a cheap 3mm tap for some time now, after accidentally breaking a TiN-coated one. It has held up very well, despite not using oil. My thoughts are that if your breaking the tap, then your technique might need some revision. With 6061-T6 aluminum I tend to start with two turns and then back off one turn, and then do three turns, and back off one, then three more, etc. However, if the tap gets stuck, I will go turn it either way without applying too much force until it gets un-stuck.

Along with the 3mm tap I'm using a 2.5mm Tin-coated drill bit that I got from McMaster-Carr at least a year ago (again, I don't use oil, except when drilling through hardened steel).

BrianG · 12:35 AM

I thought I was being careful. I even did close to what you describe (3 turns in/1 out). When it broke, I wasn't even putting much pressure turning - it just shattered. Even the drill seemed dull from the package - it simply wasn't cutting. I was thinking (hoping) it was just a bad brand or something. And of course it broke where I can't get to it to salvage the piece I was tapping. Grrr.

I'll give the plastic idea a try instead. Should be lighter too. If that doesn't work out well, I'll order a couple taps through mcmaster and give the Al another try.

aqwut · 10.13.2006, 09:46 AM

I use to use chroma tap oil.. but that SH*t was expensive.... so I used regular 10W30 Motor oil... and it works just fine... My cheap 3mm taps are just fine...

Procharged5.0 · 10.13.2006, 09:58 AM

Tap magic is affordable and works great on aluminum!

http://www.jlindustrial.com/

http://www.use-enco.com/

both excellent sources for tools, hardware, etc.

Procharged5.0 · 10.13.2006, 10:03 AM

BTW,

Make sure that the hole you drilled was large enough. it's easy to bust a tap if your tapping a hole that's too small.

use 2.5mm or .0984" for 3mm tap
use 3.3mm or .1229" for 4mm tap
use 4.2mm or .1654" for 5mm tap

Consult this for more info...............

http://www.engineersedge.com/tap_drill_chart.htm

BrianG · 10.13.2006, 11:12 AM

I was using the drill that came with the tap so the hole should have been the right size. Like I said, the drill seemed dull by comparison to the other drill bits I use. I think I will use oil next time like aqwut suggested.

Until the plastic bar stock arrives, I think I'll try another tap/drill set from my LHS and give it another go. I'll make sure to use the tips MM suggested along with oil. I think I have an odd quart of 10W30 laying around somewhere in the basement...

Procharged: Thanks! That's good info to have.