General machining question(s)

[idleprocess]

Some may have noticed the oblong aluminum pipe I was selling here.

I have some ideas on how I'd like it to end up in a finished product, but I lack good tools to work it.

I want to mill an inside and outside groove so I get male and female parts that mate together, ecapsulate lenses, endcaps, facilitate ease of assembly, etc.

I have ready access to a drill press, a router table, a shaper table, and a dremmel.

I can think of numerous ways to mill the female part, such as drilling into the center with a carefully-selected 7/8" bit, or plunge-routing it with a 7/8" plunge bit, but there are difficulties with both of those.

The only thing I can think of for the male joint is to use a router table and a straight bit to cut a groove.

Needless to say, there are problems with all approaches.

A drill press is going to have alignment issues, and using a router table for either inside or outside is likely to be hazardous even with some sort of fixture to keep the tube square with the table - not to mention preventing it from flying - an engineering challenge in it own right.

The shaper table spins at a lower RPM than routers - making for more bite and greater chance of throwing the piece.

I'm sure the ideal solution for the female piece is to use a X-Y mill and just plunge a 7/8" bit into one center, move the table 1/2", then remove the bit.

I'm at a loss for a good method on the male piece. Perhaps some sort of router guide that's an offset pattern of the footprint, and find some damn-good way to clamp the tube? Use same approach for both male and female with a smaller pattern for the female?

I know that woodworking tools might not be the best for what I'm up to, but they're all I have to work with right now. I'd imagine that carbide router bits can handle milling aluminum, but making that assumption at 30k RPM could prove hazardous...

Thanks in advance!

 

[idleprocess]

Uh, bump?

 

[DSpeck]

Yes, you can use carbide bits to work aluminum. It's not a great idea, but you can do it. Take shallow passes, since you are cutting with high speed. To make the male half, take a straight bit with a bearing (pattern follower), then replace the bearing with a smaller size. You would use this with a router table, and a large block of wood clamped to the tube to hold it in place and give it more mass to damp the machining vibrations.

Of course, BE CAREFUL! It's a dangerous way to work, so be sure to wear at least eye, ear and body protection.

Hope this helps somewhat,
Doug.

 

[Chief_Wiggum]

I suppose I'm a little confused as to what you're trying to do. You want to cut a counterbore to form a female part and then cut a shoulder to make a male part?

If so, You may be able to do it with the tools you have access to, but just remember they are woodworking tools and will not cut metal the way a lathe or mill would.

There are lots of guys with larger lathes and mills that would probably be willing to help you out. In general we don't charge much either /ubbthreads/images/graemlins/grin.gif

 

[Rothrandir]

if you're trying to do what i think you're trying to do (make a lip on the ends of these to put them together?), then you'd need to use a mill. doing the inner one wouldnt' be that difficult, if youc ould find an appropriate sized endmill, but doing the outer lip would be much harder...

i'm guessing you can't just weld them together soehow?

 

[idleprocess]

Rothrandir: Welding defeats my intent - ease of assembly.

Chief_Wiggum: Counterbore and shoulder is right. Seems like the best way to encapsulate lenses, electronics, reflectors, etc in this material since it can't be threaded along the axis. I'll just have to make the shouldered part shorter than the counterbored part to capture flat components.

If I design it right and gasket it creatively, it should be highly water resistant - although I'll have to screw into the shoulder through the counterbored part (still thinking about how to solve that problem).

If I got really fancy, I could mill a matching groove in the male and female mating walls and use an O-ring to hold things together - it would be a hell of a friction fit. Or even spline-lock it together with an insertion hole along a tangent... heh heh heh.

 

[idleprocess]

I'm sketching some of this stuff up. Perhaps I'll just have it made by someone with the right equipment, since what I'm looking at doing now is far too complicated for me to attempt.

Anyone here take AutoCAD 2002 .DWG? /ubbthreads/images/graemlins/wink.gif