Alignment Pins for glue-ups. - created 11-15-2007

Wybierala, Mark - 11/15/2007.09:06:35
Full Time Instrument Tech

A simple post about a simple thing.

I use many things to keep pieces aligned when clamping up a joint from toothpicks to drill bits. Unfortunately, this is usually a last minute consideration and it always messes up the rhythm of a job that was going well. Does anybody have a really cool thing that they use and is available in a bulk quantity so I don't need to spend time shaping toothpicks or run the risk of breaking off a 1/16" drill bit in a fret slot? I'd like steel and a consistent diameter of near 1/16"

Yes I know that this reeks of being lazy but I just had to ask.

You can get dowel pins in various materials and many sizes from a place like McMaster-Carr. I bought a box of 100 stainless steel pins for alignment purposes.

Have you used paper clips? They are cheap easily available and fit a #59 or 60 drill bit.

When I did it, I shot a staple in there, leaving a lot sticking out, then clipped it off with cutters.

Paper clips are a great idea, Steve.

PAPERCLIPS!!! Yea!

Cheap and consistent in diameter.

I was a little hesitant about posting such a dumb question but I forgot that there aren't any dumb questions. Only dumb people who don't consider paperclips.

I was on another favorite forum the other day and we were discussing shim materials for locking nuts. I use layers of aluminim foil which takes a lot of layers to be effective. Somebody chimed in with using aluminum from soda pop cans. Such a better idea.

Much Thanks. I'm off to Staples

Old model building trick(balsa wood) is to sprinkle a few grains of sand between the parts...

I use cocktail sticks - they're a nice tight fit in a 2mm hole, and you can route or saw them as soon as the glue is dry.

You can get steel drill rod, from most any shop selling metal in small diameters, for almost nothing. A couple feet of 1/16" rod costs less than a soda.

I usually have fingerboards move around quite a bit when I glue them to necks, even when I use something to keep them in place. However, the last fingerboard I glued didn't move at all. I used two small finishing nails, one in the bass side of the first fret and the other in the treble side close to the end of the fretboard in a place I knew I would remove. I was very suprised by how well they worked.

I positioned the fingerboard where it should be, taped in the nails so they entered the neck far enough to hold, and then removed the fingerboard with the nails still in it. I then glued on the fingerboard and tapped the nails in a little further, clamped, and I was done. I removed the nails after the glued had dried.

By the way, I do want to mention that tapping a nail into a fingerboard may split the wood if precautions are not taken. A pilot hole can be drilled that will lessen this possibility, but the hole should be a little smaller than the finishing nail. The nails that I used were a little larger than a fret slot, so the fret covered the hole. And tap the nail in gently looking for signs of any splitting. And, of course, don't tap the nail in too far into the neck.

I used my modified end-cutters (now they are flush-fret-end-cutters) to cut large paperclips into sections. By using the back of the cutters where the pivoting action occurs, you can get completely consistent lengths and cut thirty or so equal pins in a few minutes. Having established equal lengths is important so you can drill your holes to proper depth. The very sharp end cutters do a clean cut and the soft paperclips are safe to cut with this precision tool.

I use the staple trick, like Jamie.

One inch finishing nails, at least the ones at my local hardware store, are exactly 1/16" dia.

1/16" bits are a dime a dozen, so... Any and all of my alignment pins are 1/16". And for blind alignments, drill one hole, insert a nail cut so that only a wee bit of the pointed end protrudes, and lightly clamp your parts. You'll then have a neatly marked second part, ready for the drill, or simply leave the pointed end as your alignment pin...

I use toothpicks for a lot of things, but for fingerboards I bought a couple of lengths of brass rod from a hobby shop. It's sold in metric diameters so matching the size with a metric drill bit is no problem. (I use smaller than 1/16".) I put the pins right through a fret slot into the neck in predetermined places where I have holes in my clamping cauls.

I position and clamp the 'board, drill the holes, fit the pins into the drilled holes, remove the fingerboard from the pins, spread the glue, position the fingerboard back onto the pins, drop the caul in place with the pins in the holes (they help keep the caul in place too) and clamp. After the glue is dry I pull the pins out and the frets cover the holes.

The holes in the cauls are bigger than the pins so they slip on easily and the pins don't have to be positioned precisely. Brass doesn't rust of discolor wood when moisture is present like steel can (of coarse stainless steel doesn't either, but brass sure cuts easier), and since I usually use hide glue for fingerboards that can be an advantage.

Like John I use brass brazing rod that comes in 1/16", 3/32" and 1/8" at any welding supply place or even at hardware stores (the hardware store stuff sometimes has a white flux that you'd need to chip off first). It comes in 3 foot lengths. I've also found the 1/16" size at hobby stores in brass and aluminum in a pinch. 3 feet lasts me about ten years. I also use it to pin nuts in place since I don't use glue. I can run right over the brass with the table saw or band saw and not lose a tooth or dull the blade.

I mentioned this once before, but will bring it up again, since it fits into this discussion well. At the ASIA conference this spring Kevin Ryan was showing how he uses his CNC machine and aligns his fingerboards and necks.

He has two shallow holes in the back of the fingerboard, and has 2 matching spots on his neck. He aligns the fingerboard and his neck with these spots for machining with the CNC, and uses them for alignment when gluing. He uses small plastic pieces that remain in the neck after gluing.

I was trying to figure out what to use for alignment pins for fingerboards. I kept thinking pins, pins, pins....PINS! and needles! The fabric store had a million sizes and I assume they're all tempered steel with a sharp point. Needles especially seem to be very precisely made and as strong as anything.

I do exactly as Mario. 1" finish nails are perfect 1/16" alignment pins with centering points built in.

I use them for:

* FB's

* Headstock plates

* Align top with heel block

* Neck scarf joint

* other stuff I can't remember right now

One more vote for finish nails.

I guess I'm the only one here using a wire chimney brush.

I used to use finish nails, but have recently gone to using 1/4" wooden dowels. I have a drill jig that I use for necks and fingerboards, and I use very short dowels to align the two. I "drill" the index holes with a 1/4" spiral cut end mill so that I get a perfectly flat bottomed hole.

The main reason I went to this method is that I use those same index holes on a whole series of jigs to ensure consistency on some 5 string banjo specific alignment oddities (cutting the heel at an angle that isn't perpendicular to the apparent centerline of the neck, etc). The bigger holes don't woller out when used repeatedly on different jigs the way that smaller holes do.

Dave

We did something similar when I worked at the "banjo shop", but the holes were 1/8" and the "dowels" were plastic. You can buy plastic rods in various diameters.

It makes sense to use the holes for multiple purposes like that. As a repairman, I also like the idea of wood and plastic dowels so that when I have to take these things apart I'm less likely to damage my tools.

Yep, the repairman in me is the main reason I went with dowels (although I do use plastic rods on my jigs) instead of metal roll pins like Martin uses or other metal parts. I hate dinging up tools on a hidden piece of metal...

Dave