Best way to cut HS spar reinforcement and splice angles.

tvlawyer · #1 10-05-2006, 08:50 PM

Today I started working on tapering the HS810 reinforcement and the HS814 splice angles on the HS front spar. Tapering the pieces requires removing a substantial amount of material. I removed the material on the HS810 with a Vixen file. Man, did that take a long time! Being somewhat impatient and a little bit ADD, I thought I could remove the material from the HS814 with my bench grinder. To make a long story short, the piece hung up on the grinder and I now have an unservicable HS814 with a nice gouge across it. (Replacement already on the way!)

So, how does one properly cut and shape a chunk of aluminum angle? If I can cleanly cut the large chunk of material with some kind of saw or other cutting tool, then I can easily clean and level the edge with file, scotch-brite, etc.

DGlaeser · #2 10-05-2006, 09:20 PM

A band saw with a good bi-metalic (metal cutting) blade is what you need. And you'll use it regularly throughout your build. I have an inexpensive small band saw and get good blades from McMaster Carr.

Stephen Lindberg · #3 10-05-2006, 09:29 PM

After you rough it out on the band saw, use your disc sander to bring the cut up to the line, then finish the edge with the Scotch Bright wheel. Coupla minutes total, max. You need all those tools! Tell your wife we said so...

az_gila · #4 10-05-2006, 11:50 PM

Quote:

Originally Posted by DGlaeser

A band saw with a good bi-metalic (metal cutting) blade is what you need. And you'll use it regularly throughout your build. I have an inexpensive small band saw and get good blades from McMaster Carr.

Band saw yes... but a wood cutting blade is OK... the very fine tooth metal cutting blades will clog up with the relatively soft aluminum.

Then use the sanding disk/belt....

This is OK at the normal running speeds of the bench top band saws... even Delta says it's OK.....

http://www.deltamachinery.com/index.asp?e=139&p=1459

gil in Tucson

Rick6a · #5 10-06-2006, 05:41 AM

Quote:

Originally Posted by tvlawyer

So, how does one properly cut and shape a chunk of aluminum angle? If I can cleanly cut the large chunk of material with some kind of saw or other cutting tool, then I can easily clean and level the edge with file, scotch-brite, etc.

An alternative to the bandsaw and at at times even more efficient is to use is a fiber cutoff wheel fitted to a die grinder. This is the same disc you will use to eventually split the canopy glass with. You can (to a limited extent) even dress the ends of the work by applying a side load to the fiber disc as you would when using a bench sander. Safety first. For smaller jobs such as cutting through sheet up to .032 thick or so, you can even use a Dremel tool or similiar using the smaller cut off wheels designed for them. For cleaner cuts and less strain on your tools, make several shallow passes rather than trying to do it all in one pass.

tvlawyer · #6 10-13-2006, 05:54 AM

After receiving my replacement HS-814 from Van's, I rought cut the shape with an air powered cut-off wheel. I brought the edge up to the line with the disk sander. (I bought the $99 Ryobi disk/belt sander from Home Depot. It looks like that will prove to be a good investment) I smoothed the edges with a couple of passes on the scotchbrite wheel and, voila!, done in 30 minutes and it looks just like it does in the plans.

Thanks to all for the advice.

Brantel · #7 10-13-2006, 06:21 AM

Grinding on aluminum with a bench grinder is asking for a trip to the emergency room. The wheel can explode due to the buildup of aluminum.
I have seen this happen and it is not pretty.

Ironflight · #8 10-13-2006, 06:27 AM

Quote:

Originally Posted by tvlawyer

After receiving my replacement HS-814 from Van's, I rought cut the shape with an air powered cut-off wheel. I brought the edge up to the line with the disk sander. (I bought the $99 Ryobi disk/belt sander from Home Depot. It looks like that will prove to be a good investment) I smoothed the edges with a couple of passes on the scotchbrite wheel and, voila!, done in 30 minutes and it looks just like it does in the plans.

Yup, I love my band saw, but if I had to make a choice between it and the sander, I'd keep the disk/belt sander for final shaping of aluminum chunks - I basically wore my Delta machine out building the Valkyrie - great for ending up with a nice straight edge!

(And no, I wouldn't really want to give up my band saw either...)

Paul

tvlawyer · #9 10-13-2006, 06:42 AM

Quote:

Originally Posted by Brantel

Grinding on aluminum with a bench grinder is asking for a trip to the emergency room. The wheel can explode due to the buildup of aluminum.
I have seen this happen and it is not pretty.

Yep. You make the third person to give me that bit o' advice. So, I took that wheel off the grinder and tossed it.

N941WR · #10 10-13-2006, 06:51 AM

mix steel and aluminum on the same belts.

The reason is you will push steel into the aluminum part which will cause dissimilar metal corrosion.

I use my $10 14" garage sale bandsaw to cut the pieces, sand them to size on the bench grinder, and finally remove the sanding marks on the deburring wheel chucked in the drill press.

If you can't find a good deal on a bandsaw try picking up a body saw. (They are on sale for $19.99) I have found 101 uses for mine.