Brace and Bit use question

[Tony Wilkins]

Working on my Moxon vise using Bench Crafted hardware and I ran into a problem when using my Brace and bit to do the holes: Here's the particulars:

Wood: 8/4 walnut
Bit: vintage Irwin 3/4 (the spur and the ramp seem sharp)
Brace #1: Bell System 8" sweep (used on the first hole)*
Brace #2: Fray Spofford 12" sweep (used on second hole)

The Problem: the bit goes about 1/2 way in and basically stops cutting. I've backed them out and cleaned out the hole but no joy.

The question (at long last): How do I get all the way through? Did I do something wrong?

The one idea I have is to get my hand drill out and go the rest of the way through with a bit smaller than the lead screw as to line up the holes and start in from the other side.

TIA,
Tony

*if anyone wants to trade my 8" bell system for an 8" or 10" Spofford I'm open to doing so.

[Hilton Ralphs]

Are you sure the overall diameter of the bit is consistent along its length? It sounds like perhaps the previous owner sharpened the auger bit on the outside of the spurs which is a no-no.

[Tony Wilkins]

I'll check that later, didn't know that Hilton.

[Jim Koepke]

Hilton describes one of the most common problems with auger bits, improper sharpening.

The spurs need to be sharpened on the inside only.

The ramps, cutting lips, should only be sharpened on the top side.

Both lips should be taking the same sized chip when cutting.

For the best, consistent results, the spurs should be scribing a full circle before the ramps touch the wood.

Depending on what is being bored and how close to an end grain edge a small pilot hole can be very helpful. The pilot hole needs to be a good deal smaller than the lead screw of the auger bit.

Another problem you may be having is the lead screw itself. There are many kinds of auger bits. One distinction is bits made for hardwoods versus bits made for softwoods. Softwood bits have a coarser lead screw to pull them through the wood faster. In some hardwoods these can strip out when the spurs and lips can't cut fast enough to keep up. Added pressure on the brace might help.

Here is a post with more information on auger bits:

http://www.sawmillcreek.org/showthread.php?131238-A-Bit-About-Augers/page2&p=1367250

There is an additional links at the end of the thread with some close ups of bits to show what they should and shouldn't look like:

http://www.sawmillcreek.org/showthread.php?167266-Auger-bit-question&p=1717755#post1717755

jtk

[Tony Wilkins]

Thanks for all the info Jim. First blush is that it is sharpened correctly but I'll get the bit and compare it to all the info you provided. Am I wrong in remembering that both types of lead screws should work in hardwood (walnut) but it is the hardwood screw that won't work in softwood?

[Jim Koepke]

Thanks for all the info Jim. First blush is that it is sharpened correctly but I'll get the bit and compare it to all the info you provided. Am I wrong in remembering that both types of lead screws should work in hardwood (walnut) but it is the hardwood screw that won't work in softwood?

You are welcome.

My understanding may be wrong, but I think hardwood bits are slow in softwood and softwood bits are likely to strip the wood treads in the bore hole from being too aggressive.

jtk

[Tony Wilkins]

It is definitely a lead screw problem. The spurs and ramps seem to be sharpened pretty well. It works perfectly until a certain point and then just stops pulling it down into the wood. I looked at the screw and they seem pretty coarse. I have to find my ATC to look up which is which.

[Adam Maxwell]

It is definitely a lead screw problem. The spurs and ramps seem to be sharpened pretty well. It works perfectly until a certain point and then just stops pulling it down into the wood. I looked at the screw and they seem pretty coarse. I have to find my ATC to look up which is which.

Jim already suggested using more down pressure, and that should do it. Once the lead screw loses its bite or gets plugged, you have to do the job for it, and it's nothing to get too worried about as long as the spurs are correct.

I'm hesitant to start an argument over which bits are for hardwood vs. softwood, but I'll note that my Russell Jennings bits are listed as for "seasoned woods not extremely gummy or hard." The lead screw on the RJ bits has two starts, in spite of appearing to have more threads per inch, and in my experience they work pretty well in mahogany, okay in tulip poplar, and totally stink in hard maple. The Irwins are a much better all-around bit, especially for hard woods, though they're slightly slower. Josh Clark has written more extensively on this, either here or in the oldtools list archives, but not everyone agrees.

[Tony Wilkins]

That's what I'm doing now Adam (more downward pressure). Slow going. This is where a tall bench and weak arms don't serve me too well.

[Adam Maxwell]

I hear you. If you can put the piece on the floor or a sawhorse and get upper body weight on it, that can help, or bore horizontally and push on the brace pad with your midsection. I've heard people say that the lead screw should do all the work, but it seldom does for me, at least with deeper holes; I bore most of my holes by hand, so I'm used to just doing whatever it takes. The set of bitstock Forstners that I just got seem to require substantial pressure to keep cutting.

[Jim Koepke]

This is where a tall bench and weak arms don't serve me too well.

I use a step stool often in such cases. Or like Adam suggests do the boring horizontally.

jtk

[Mike Holbrook]

I read an article that suggested that the Owl, Nail Chipper, Tri Cut drill bits are much faster and easier to use in a brace and bit, especially for big, deep holes. I have not gotten around to buying one to try them out yet. They are available from Traditional Woodworker. Might be worth looking into.

The Nail Chippper, being designed to go through nails, reportedly leaves a slightly ragged hole. Owl makes a bit designed to leave a neater hole too, Ultra Smooth. The Nail Chipper is the one that is suppose to power through any kind of wood at a faster rate though.

PS: I ordered a Nail Chipper and a Ultra Smooth to try. I will post my findings once I get them.

[Curt Putnam]

Mike: Note that the Wood Owl bits are designed for power drills - not hand powered braces.

[peter gagliardi]

I'm pretty sure ALL of the Irwin's utilize the coarse thread lead screw which is bad for hardwood. Add to that that they also utilize the single flute cutting geometry, and it is a bad recipe for your needs. Try flea markets, tag sales, even the "bay",
And buy yourself a set of the "Jennings" pattern bits with a tight lead screw, and not abusively sharpened- problem solved!
They ARE the definitive best bits for your need bar none!! The Irwin's are great for pine, not much else!

[Chris Vandiver]

In any case, boring the hole from both sides of the board is usually the best way to go, especially if the hole needs to be accurately done.

[Kees Heiden]

Overhere in mainland Europe, the Jenning bits are rare, while the Irwin pattern is everywhere. So, I only have the latter. They haven't been a problem yet in oak, beech, wallnut, ash. In fact, they work very well in these kinds of wood. When they are sharp of course.

[Bob Glenn]

Is the auger bit clearing out the chips? If the auger is clogging, there is no place for the chips to go and the screw tip will strip out in the wood since it can no longer pull the cutting edges into fresh wood. It will just sit there and turn. To check, drill down until it seems to stop cutting, then back out a few turns and pull the bit out of the hole. Clear the chips and see if the bit will continue to drill. Let us know what happens. Good luck. Bob

[Adam Maxwell]

Overhere in mainland Europe, the Jenning bits are rare, while the Irwin pattern is everywhere. So, I only have the latter. They haven't been a problem yet in oak, beech, wallnut, ash. In fact, they work very well in these kinds of wood. When they are sharp of course.

This is why I think you shouldn't even bother looking for Jennings pattern bits. The supposed "fine" thread on many of them is actually a double thread; it has two starts, which makes it a coarse thread which is also very shallow, and strips easily. The Jennings bits work well in dry mahogany, walnut and similarly soft (in the Janka sense) woods…as it says on the spiffy 3-tier wooden box. They pretty much suck otherwise, but this lets tool sellers claim that RJs are the preferred bit of cabinetmakers.

There are apparently RJ bits in existence with a single-thread lead screw, as Alf showed in a blog post on this topic (wish I could link it here; look back to Feb 21 2013 on cornishworkshop.blogspot.com). I can't find any of these in my stash, so I'm not sure how common they are in the wild. I'd certainly be willing to revisit my boring tests if someone wanted to send me a set of them…

I believe a previous poster indicated that Irwin bits have a single cutting edge, but most have two flukes and two spurs; one of the flukes just dead-ends, so it's still a single-twist bit. As I've said, in my experience, beat-up Irwin bits will outperform my NOS RJ bits in hard maple or doug fir, hands down, and they're certainly capable in softer woods as well.

[Hilton Ralphs]

Was it just a fluke that you mentioned fluke twice or were you just blowing your own flute? :)

[Adam Maxwell]

Was it just a fluke that you mentioned fluke twice or were you just blowing your own flute? :)

Ugh. That's what I get for writing before drinking coffee.

[Chuck Nickerson]

There are apparently RJ bits in existence with a single-thread lead screw, as Alf showed in a blog post on this topic (wish I could link it here; look back to Feb 21 2013 on cornishworkshop.blogspot.com). I can't find any of these in my stash, so I'm not sure how common they are in the wild. I'd certainly be willing to revisit my boring tests if someone wanted to send me a set of them…

After extensive searching I found an 'almost' set of these ( they're model 101); one of the bits was a routine model 100.
They are a double lead screw and are better at pulling the bit into the wood.

Getting back to the OP's original question, I'm betting it's the sharpening of the flutes. If they're even .002 smaller in diameter, in a deep hole it starts to matter. This can be cured fairly quickly by dressing down the widest parts of the spiral with a coarse stone or sandpaper or grinder or...

I've done this twice with unusual-size bits: a #3 RJ 100 and a #3 Irwin.