Enlarging hole in tailpiece - drill or file?

[Clement Barrera-Ng]

Hi all,

Been reading up on some of the old threads on how to install an end pin pickup jack. However, I didn't find much mention on how to properly enlarge the hole in the tailpiece to allow the endpin jack to fit through. Do you use a drill, or file? Or is there some other way to cut out the larger hole that I didn't think of before?

My last attempt began with a drill, which didn't turn out so well. So I finished the hole off with a file. While it works, the cut is not clean and the hole uneven.

Thanks!

[sunburst]

A reamer would be best. A file, while slow, can do a good job. Drilling would require a jig in a drill press, and even then it can be chancy to enlarge holes in thin metal with a drill bit.

[Clement Barrera-Ng]

Thanks John. Would a reamer still work if the enlargement is done off-center? At least in my case, I find that if I were to proportionately enlarge the hole on all sides (like a series of concentric circles), I risk having the hole in the end block cut into the top plate on the mandolin. Instead, I try to line up the top edge of the enlarge hole with the top the of original hole, and attempt to do all of the cutting from the bottom of the original hole. The end result is a large hole that centers lower than the original one.

[sunburst]

You need to file it, or use a die grinder in a Dremel or other rotary tool.

[Clement Barrera-Ng]

Ah a rotary grinder tool! Of course. Thanks for the suggestion John.

[jim simpson]

I screwed up the one time I tried with a hand drill. The jack didn't seat on one side but was secure and fortunately not too noticible. I wanted to plug in with my rock band and had an oval hole Washburn. I made my own pickup from a piezo disc. I would have used a reamer if I owned one back then.

[RBMB]

Is it the size of a .22.44 ...?

[Rroyd]

A rattail file can be used to enlarge holes in wood and metal both, and can be chucked in a drill to speed the process, but the critical factor that must be adhered to is that the drill must be run in reverse. Otherwise the spiral teeth on the file will cause it to try to screw itself into the hole, usually with disasterous consequences. With the drill reversed, it is easy to maintain complete control over the work.
I have somtimes cut off or shortened the tangs to make it easier to chuck them in a drill, and there have been times I have used a hand-operated brace. I have enlarged holes in 3/4 inch steel plate using this technique, as well as fitting an endpin or two. (before I purchased an appropriate endpin reamer)

[Mattg]

I just did this on my Eastman 615 and used a three step process.

1. First I used a reamer to enlarge the hole in the cast tailpiece.

Next, I measured the thickness of the hole that needed to be drilled and marked it on the bit so that I could drill very near the total depth but not all the way through. As mentioned in a previous post, if you try to drill all the way through, it will grab the bit and splinter the hole on the inside.

C. Then I used a rat tail file to enlarge the very last bit of the hole.

I used an electric hand drill. A drill press is not necessary. The whole thing was much easier than I thought it would be.