Timber Framers Guild

Boring machine

Posted By: Gumphri

Boring machine - 04/21/10 04:43 AM

My new to me boring machine just came in the mail today. I'm not 100% sure on the make but I think its a Snell. They aren't common in my area and mine is the first I've seen more than videos of. I tested it out today on an old chunk of spruce. On three separate holes my only bit(1 1/2") spun out about 1/4" into the wood. Is there a technique like putting weight onto it or something I'm missing. Or is it just that my bit is a bit dull?

Is there a technique different from sharpening a standard auger bit that I need to know about before I try to sharpen it?

Thanks,

Leslie Ball
Posted By: TIMBEAL

Re: Boring machine - 04/21/10 11:08 AM

Well, how sharp is the bit? Are the feed screw threads in good shape? Some are rusty and missing their edge, dull too. the cutters should be able to catch your finger nail as you drag or try to drag/ scrape the face of your finger nail across the edge, just like any cutting tool. I like my bit to sound clean, a dull bit will make more of a grinding noise and the 1/2 chip will look ragged, look for scratch marks in the chip.

I use a small flat file and a small triangular file, the finer the cut the better. I don't polish with stones etc., just the fine file. Keep the cutting edge the lowest point, you don't want any other part of the bit touching the wood first, the edge needs to lead. Another good video possibility.

Try it in fresh wood, you will get a different result just by boring green wood. You should not have to apply pressure. There are exceptions, pitch pockets, peg holes, frozen wood, and at times knots all effect the feed screw. Spruce is just stubborn, also try it on other species to get a full understanding.

In frozen wood I have had to bore a 1/8" pilot hole to get through frozen sap wood, once in heart wood it pulls fine.

Tim
Posted By: Jim Rogers

Re: Boring machine - 04/21/10 11:47 AM

Leslie:
As Tim has mentioned it could be that the lead screw is getting filled up with wood fibers and not clearing properly, meaning that it could be the wood and not the bit.

You can look at the threads and see if they are damaged and need cleaning.

Understand how to sharpen your bits is also important.
You can use a special "bit sharpening file" to sharpen it.

These files have cutters on the sides on one end, and cutters on the flats on the other end, so that when you are filing your bit you don't "over file" some place other then where you actually want to file.
And never file the outside of the wings, as this would change the diameter of the hole you want to bore. Only file the inside of the wings.

Good luck.

Jim Rogers
Posted By: TIMBEAL

Re: Boring machine - 04/21/10 10:39 PM

Wings, thats what they are called. they cut the fibers while the big cutters on the bottom lift the chip out. If the bit is rusty you will have to shine the outside of the wings just a tad, don't over do it. If they are polished and not pitted then do not touch them on the outside, as Jim points out.

Tim
Posted By: Gumphri

Re: Boring machine - 04/22/10 03:25 AM

Thanks for tips. I'm going to sharpen the bit and try it again on a greener piece of wood. While I'm at it I will clean up the machine. It appears as if it has been sitting in a barn for awhile. All the parts are there and in decent condition. It just needs some tlc.
Posted By: Gumphri

Re: Boring machine - 04/27/10 01:03 AM

Well, I sharpened the bit and it worked as prescribed in the same 2 year old piece of end cut spruce. I'll just have to get a bit of practice before I race my friend with the makita mortiser.

Thanks,

Leslie Ball
Posted By: TIMBEAL

Re: Boring machine - 04/27/10 01:15 AM

I adapted a bit like this to my boring machine bit selection, it makes a big difference. Worth a try. I used a chuck on a hand crank breast drill, it had a 1/2" shaft with the chuck attached, fits right into the boring machine chuck. I hope that makes sense.

http://www.toolup.com/irwin/49924.html

Tim
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