Official Luthiers Forum!

Hey folks,

I'm in the process of gluing a replacement bridge on a steel string acoustic. I got a set of bridge locating index pins from stew mac. But I'm having a tough time using them. These are conical nylon bridge pins with a 3 degree taper to them.

The trouble is the holes in the guitar top and bridge plate are too big. So the index pins won't work to hold the bridge in place. I tried drilling small holes in the caul I'm using under the bridge plate and reaming these. In the process, I seem to have over-reamed the holes in my bridge. The pins are not snugging into place and will slip out easily. Keep in mind I haven't glued the bridge on yet.

Thoughts on what to do? I was thinking, perhaps I could drip a bit of stick lacquer into the bridge pin holes, then ream them smooth and too a lesser size

Thanks for any advice,

Stefan

If the pin holes through the top and plate inside are worn or otherwise oversized I would put in new wood. Either wrap a plane shave around a pin and glue it in if it is slightly oversize (wrap the pin in scotch tape so it doesn't get glued in too). Or use the SM bridge plate repair tool if it is really bad.

Alternately you could index the bridge by measuring the position and using two small wooden dowels placed in the saddle slot (round toothpicks work well) and then deal with the pin holes after gluing the bridge back on with some oversize pins.

_________________
Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

Thanks for the advice, Brian

One question, could you use the plane shaving trick to make the tapered hole in the bridge smaller as well as the hole in the top/bridge plate? Or should I just order oversized pins , or make a new bridge (it will be #4 in this project, fun times learning this )

I do a fair number of bridge repairs and made up some cauls that I find quite useful. It is UHMW so glue won't stick and it has two slots that take 3/16 bolts. The slots allow me to fit different pin spacing. Here it is on a new guitar, it works just the same on a reglue





The 3/16 bolt is the same size as the drill that I use for the pins themselves.

If you need to fill the holes and redrill them StewMac makes a tool to cut the bridge plate from inside and plug with new wood. Another option is to work a little bit of CA on the insides of the holes, that might be just enough to tighten them up. Last option might be oversized pins.

The shavings get glued into the bridge and guitar at the same time,you need to glue in two of the shavings when you glue the bridge down using two pins to index and then glue the other four after.

I would need to see it in person to give an opinion on best approach.

_________________
Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

I fill the hole with a straight dowel of the same wood. After it dries I use one of these "Snug Plug" cutters from LV http://www.leevalley.com/us/wood/page.aspx?p=32320&cat=1,180,42288 in the top with matching wood/grain orientation. The re-drill and sneak up on the taper depth. It does an excellent job and what little tearout happens in the edge of the hole is easily filled with CA and fine sawdust.