New Circle Cutter

[truflite]

Being a part time machinist, my guess is that the bit is High Speed Steel (HSS). Slowing the speed down will help, but just delays the inevitable. If the blade can be removed, and looks like a normal bit, you should be able to find a carbide bit to replace it for stainless work. Go slow as suggested above as the bit will grab and turn your stainless into scrap at high speed. Take your time and you should get a perfect hole.

303 Stainless is free machining although shallower cuts, slower speeds and feeds are required.

304 Stainless will eat carbide for breakfast if you go just a little to fast or heavy cut. And forget about tapping it by hand.

Ask me how I know.

[rv8ch]

Originally Posted by cka357

There's tons of drill bit suppliers on the net. I use MSC for my source. They are quick to deliver. They give you a good description of the bit material and coatings when using their sort menu.

http://www1.mscdirect.com/cgi/nnsrhm

Search for aircraft drills.

Cleveland or Precision Twist Drill are two quality manufacturers.
The 135 degree split point really helps to prevent bit walking as well.

Chuck

Chuck, thanks for the tip on MSC Direct - I have not visited their website in a long time and I can see it's really made a lot of improvement!

Regards,
Mickey

[David Paule]

I bought one of these, a Malco HC-1, from Amazon to cut the lightening holes in the wing ribs of my RV-3B. The holes were very easy to cut, with none of the danger associated with a fly-cutter.



For these holes, it was hard to clamp them down and still get a full swing of the tool. I started with this corner clamp and one more, and later added a third and removed the corner clamp - for each rib.

Since the tool rides on a pilot, when I got near the end of the cut, I had to be sure that the tool was firmly pressed against the backing wood piece to keep it from wandering. This wasn't hard and there were simply no issues at all. All 23 cuts went real easy. Yes, the RV-3B wings are symmetric - I made a practice cut before attempting the ribs.

I used a Sioux air drill and used about 95 psi. My compressor needed to recharge five times for the drilling.

The hole was slightly rough and needed cleaning up. I used a drum sander in the drill press for that, finishing off with a Scotchbrite drum in an air die grinder. A piece of 220 grit sandpaper would have done as well, been quieter and taken considerably longer. With the air die grinder going, the air compressor was on constantly, but never dropped below 100 psi. I was running about 95 to the grinder motor.

Dave

[terrye]

Originally Posted by aparchment

Nice! I wonder how the bit would stand up to the stainless firewall.

I got one of the Rotabroach kits from one of the usual tool suppliers. Sizes 5/16" to 3/4". These work excellent on the SS firewall. Also work excellent on aluminum.
http://www.hougen.com/cutters/kits/a...tter_kits.html

[drb930]

Sweet!!!
Just what I was looking for...

[John R. Graham]

The fly cutter has always scared me. I'm going to get one of these very soon. You've gotta love the Van's community.

- John

[tomhanaway]

Has anyone used this tool to cut access plates in rear of fuel tank when the tank is already built?

Wondering whether there's enough clearance for the tool to clear the skins when cutting into rear baffle.

Thanks,
Tom H.

[Ron RV8]

I have used one to cut access holes in the rear baffle. You only get part arcs however before the frame hits the flange on the baffle. I finished mine freehand with a dremel and carbide burr designed for aluminum, then a sanding drum in a drill.

[mbell]

I just sawed an inch or so off the handle of the tool.

[exercise]

Hi Guys,

I just cut my first panel using a Malco hole cutter and each hole came out perfectly. Using a cordless drill, it took about 60 seconds per hole and is completely safe. I laid the panel down on a piece of pink styrofoam board to do the cutting. My neighbor loaned the cutter to me. Turns out that he helped design this tool way back when. One third the cost of a hole punch and adjustable to just about any size hole you want.