Drilling balsa - Great Godfrey!

A Forstner bit (especially one with a fine center spur) is supposed to do a good job, if you can find one that small. They're a woodworking bit (oddly enough, given that balsa is wood...). I've used a brass tube of the appropriate diameter with saw teeth filed in the end -- but it's hard to get the teeth set right, it's a pain to file them. I've seen holes cut with a Forstner bit and they look very nice -- the brass-tube hole saw approach seems to tear the balsa more.

You can buy hole saws at Home Depot or Lowes that work great for drilling balsa----IF you use a drill press. Use a piece of pine or poplar to back the balsa and drill away.

LeeH wrote in news: snipped-for-privacy@centurytel.net:

I use rifle or pistol empty shell casing with edges sharpened, select caliber for size of hole desired, and do one at a time. Short piece of copper tubing would do, to. However, you may be able to drill through a piece of hardware store grade thin plywood or thicker aircraft grade (I'd go with at least 1/8 inch) cut to shape of the rib, this should provide enough rigidity to keep the first rib intact, provided your bit is sharp enough.

High speed, do you have a Dremel? I use a cutting bit. You can make holes in 2 or 3 ribs at a time and make them just the shape of the plug, maybe

Dremel with cutting bit! Yassir. With a steady hand, makes holes any size/shape, looks almost like laser cut. Bill(oc)

Are you talking about holes ¾", or larger That is the smallest size that I can find for a Hole Saw. If you know where to find Hole Saws down to 3/8", or ½" Please, would you say where to get them ?

Wayne

The set I have goes to 9/16" and although I do not remember for sure where I got it about 30 years ago, just plug in hole saws on a search engine; and you will find them. The 1/2" and 3/8" were made for me by a friend in the tool and die business for the furniture business. They have their own arbors. If you know anyone in this business, you should be able to get them made.

Marvin & Sue

Tim Wescott wrote in news: snipped-for-privacy@corp.supernews.com:

Okay, I had to go out to the garage to check, but I have a set of Forstner bits that goes all the way down to 1/4" - and, yes, there's a 3/8" bit.

So I'd go with the Forstner bit . . . unless . . .

If there are going to be servo extensions permanently built into the wing, then the other choice would be to drill a pair of 1/8" holes, about half an inch apart (horizontally) and then use an Xacto to join them, making an

Some 9mm ammunition comes loaded in steel casings. Find one of these. Brass will work too, but probably won't hold the cutting edge as long - still. Using a file, remove the rim material along the inside circumference of the shell casing (bullet/powder removed and primer discharged). Do this so that the outer edge of the shell casing comes to a point, all around the opening. Be patient and take your time sharpening the inside of the rim.

When wanting to make a hole in a rib, simply place the rib on top of a piece of scrap lumber, place the sharpened end of the shell casing where you want the hole and then tap lightly with a small mallet several times. I use a novelty/decorative wooden hammer that my wife gave me over thirty years ago for such purposes, but any hammer will do. Just be sure that the casing is square on the balsa to be cut before tapping and go lightly. That's it.

A .45 casing might be better for most apps, now that I think of it.

Ed Cregger

This is a good method too and it works for coarser grained wood.

Ed Cregger

I have adapted a pair of draughtsman's springbows and fitted a pointed scalpel bade to them.

Works fine cutting through balsa ribs etc one at a time.

Griff.

Thank You for your suggestions.

Wayne

A hole saw, and run the drill backwards. It'll basically sand it's way through the balsa. I've done this with

--- Rich

Use a piece of brass tubing sharpened on the end. Dosen't need teeth as they will tend to tear the balsa. Just chuck it up in your drill and hold a file or even a piece of sandpaper against the end as you spin it and this will sharpen it good enough. Try this on a piece of scrap. I think you'll be surprised how neat the holes are. Lay a piece of scrap over the stack of ribs when you drill as this will keep the hole in the top rib from tearing any. I can send you some pics of ribs that I cut like this if you would like. I'm sure there are other ways but this works good for me.

Ken Day.

OOOPS.... forgot to tell you to sharpen the INSIDE of the tube , not the outside. Also , I always get a better job doing one rib at a time.

Ken Day

I believe the idea is to use a sharpened piece of old TX antenna.

Only problem with that idea is if the lead goes bad in some way and forces you to thread a new one in after the wing is covered.

"Chuck Jones" wrote in news:dNWye.54151$iU.10507@lakeread05:

True. I haven't run into that problem yet - more likely to have a break in the lead that's soldered to the servo (which, of course, is much easier to get to). Still, if you have to thread another lead through, it can be done if you're careful and if you DON'T PULL OUT THE BAD LEAD BEFOREHAND. Just plug the new lead into one end of the old one, put some tape or some such over the connection to make sure it doesn't come apart in the wing, and then carefully pull on the old lead to pull the new one through the wing. This will take some jiggling of the wing to help when the connector snags on a rib, but it can be done. You can use a little masking tape to sort of streamline the connector, too, to reduce the snags.

Of course, I usually put in paper tubes.

I wonder if there is a tube with diamond dust or carborundum imbeded in the rim. Or how about drillling a small pilot hole and inserting a tapered dowl that has sandpaper glued to it? Chuck it in a variable speed drill. It would only do one at a time if it worked at all.