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My son wants me to install a kk pure mini in his Gibson TV J45, the endpin is held in by a screw so there is no hole to start a reamer, what type/size of drill would be best for drilling the pilot hole for the reamer? All the best Roby

Hey Roby: I use the smallest brad point bit that is larger than the small end of the reamer. I think that's 1/4" but I am not in the shop at present to check out my reamer.

Be careful not to ream the hole to 1/2" as the whole world does and manufacturers suggest. It's not necessary, causes a sloppy fit, and contributes to the jack coming loose in time.

Here's a link to our Facebook page where David Collins has a pictorial toot about reaming end jacks: https://www.facebook.com/a2guitars/photos/ms.c.eJw9zMENwDAIQ9GNKjsEMPsv1jQkPT592aQFEPRJS~_BhuwYE8zrO8fXQ72j7sbrn7eq9XZcp57pnm~_DuI69j9SjpmL7~;Zrzn2h~_~;.bps.a.113600518747043.19651.100681526705609/113600615413700/?type=3&theater

the best drill bit is a simple step drill . they don't tear things up. Running a pilot hole won't hurt but it isn't necessary . here is a link to a set the longer bit is the one I use for this.
I am a K&K dealer the mini pick up unless you get the vintage jack will take a typical 1/2 in hole., if your using the vintage jack a 1/4 in hole is what you need but again I use the step drill to the 1/4 in point then use a standard 1/4 in to complete the hole. The step bits really help to avoid tear out , and place tape over the guitar and make a mark to the point you want to drill.
Take your time seating the vintage jack , I like to get it just about flush then use a chamfer bit to dress off the corners of the hole then set the vintage jack flush.
It comes with some rosin that helps the jack to stick. Should you over set the jack you can paint the hole with some elmers glue let dry and you will be golden.

http://www.ebay.com/itm/New-3Pcs-set-St ... rkt%3D1%26

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Thanks guys, great information.

It sounds as though you already have a reamer of the correct size, and there is already a threaded screw hole, so the task is not to start a hole in a guitar without a tailpin, but instead, to keep the pilot hole centered on the screw hole and make it large enough to take a reamer while avoiding any finish damage.

Mr. Hall's suggestion of using a small step drill is a good one because the 1/8" lead (the first step) has a conical tip that will remain centered on the existing hole and should not lift the finish. Because the most common size step drill set has a bit with increments of 1/32" from 1/8" up to 1/2", it is also useful for milling the hole to the final 15/32" (12mm) size that Mr. Breakstone recommends if you do not - in fact - have a one-step reamer such as the Stewart-MacDonald tool, and must finish with a chucked reamer to 15/32" or 12mm size. After reaming, careful use of the step drill or an appropriate countersink will ease the edge of the hole and prevent the finish from chipping when the jack is inserted.

While we use brad points (1/8" to 3/16" size) here in the shop to start tail pin holes in guitars that do not have them, I am concerned that the existing threaded hole will be much too large to keep the tiny center point of a 1/8" or 3/16" brad point in place, which will allow a brad point's center spur to wander with a potential for causing some issues. Likewise, a split-point twist drill may also wander where the tip design cannot properly register, and the cutting action will lift the finish, causing finish delamination and chipping. As Mr. Hall mentioned above, a step drill, which cuts with a scraping action, is a better choice for the job, and is commonly available at Home Depot, Lowes, any hardware store worthy of the name.

Another choice which works well, but likely not available at your local hardware store, is a centering drill. We keep these around for opening small, threaded holes to larger size, and they have the same reaming action as step drills.

One last point - even a modified twist drill as described in some installation guides is a poor substitute for a good step drill & reamer combo or the Stewart MacDonald tool. In just the last year, we're repaired three instruments with major finish and trim damage from well-intentioned pickup installation efforts on the part of owners or helpful friends. The cost of even the least expensive of these repairs exceeded the cost of the proper tools by a good bit, so a $15 step drill/$18 reamer or the $75 Stewart MacDonald tool are both economical choices compared to the 1.5, 2.7, or 4.1 hours we billed out to those customers for repair. And then we charged them again for doing the job right! Ouch!

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A constellation only takes shape when one maps the whole.
- Beth Brower

Tailblock inlays can make any amount of off center look obvious. One of the beautys of using a tapered reamer with asymmetric cutting edges, such as Stew Mac's, is it allows "moving" the hole slightly as you go.
Nothing says Amateur install job to me as quickly as the sight of a jack anything less than perfectly centered.

as John said!

Mike

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Mike Collins