Drill a small-diameter pilot hole, THEN a large-diameter finished hole? Or not? [Archive]

Tom Burgess

11-27-2021, 12:38 PM

Hi, all.

I need to drill two 3/8" holes approximately 1" deep into a basswood electric guitar body.

The holes need to be PERFECTLY(!) located/positioned. They mount the bridge to the guitar body, and any mistake will render the instrument 'firewood.' I'll use a drill press, and clamp the workpiece firmly in place.

Basswood is considered a hardwood, but a "soft hardwood." I find it to be rigid and dry, and easy to work.

I read somewhere online that drilling a smaller-diameter pilot hole is actually counterproductive because, "then the 3/8" bit is not cutting wood from the center of the bit" or words to that effect. Apprently that might allow the bit to wander...

I hope that's not true. In this case I want to drill the smaller pilot hole all the way through. Why? Each 3/8" hole accepts a press-in threaded metal anchor that is splined. A relatively tight interference fit is the result. See attached photo. Drilling a smaller pilot hole all the way through the guitar body will make it possible to press that anchor OUT from below if or when I need to.

468837

Zachary Hoyt

11-27-2021, 1:00 PM

It sounds to me like you could drill the larger hole first and then drill a smaller hole the rest of the way through from the bottom of the big hole, and that would solve both problems.

Tom Burgess

11-27-2021, 1:27 PM

Agreed, but I'd rather drill that pilot hole first. And I will IF drilling the smaller pilot hole is not likely to cause the 3/8" bit to wander.

I'm clamping the workpiece to the drill press table, but even so, if a drill can go in some arbitrary "other direction," it will.

So the question remains:
Will a pilot hole drilled in wood increase the chance of the larger finished-hole drill wandering?

Stan Calow

11-27-2021, 1:44 PM

What kind of bits are you proposing to use? Brad point? Forstner?

Jonathan Jung

11-27-2021, 2:07 PM

I've found my Fisch forstner bits can follow a 1/8" pilot well.

Paul F Franklin

11-27-2021, 2:14 PM

I don't know if the pilot hole would cause the larger bit to wander; I do know a small diameter bit is more likely to be deflected by grain in the workpiece than the larger bit would be, so it might be counterproductive for that reason.

If I need holes to be perfectly positioned, I make a drill guide out of hardwood or better, something like phenolic that has no grain. Use stock at least 1/2" thick. You can take as many tries at making the guide as necessary to get it perfect. Then you clamp the guide to the workpiece, in this case your guitar, and drill the money holes. You may even be able to make the guide such that it registers on something like the sound hole or edges of the piece so both spacing and absolute position of the holes is set exactly.

Tom Burgess

11-27-2021, 2:17 PM

What kind of bits are you proposing to use? Brad point? Forstner?

Just a standard twist drill for the 3/8" holes, but might consider a Forstner bit per Jonathan Jung's comment #5.

See my reply to his comment for further reasoning regarding use of a Forstner bit.

Richard Coers

11-27-2021, 2:17 PM

For the most accurate work, use metal working tools. Start with an optical center punch. Then if you will use a pointed drill, drill with that. If you use a twist drill, use a center drill.

Tom Burgess

11-27-2021, 2:42 PM

Thanks for introducing Forstner bits into the discussion.

Experimenting on pine/spruce 1x4 scrap, I found that a 3/8" twist drill hole drilled near the endgrain edge (simulating placement of the hole in the actual guitar body) was problematic. Insertion of the anchor required too much pressure, so much that the wood cracked. So I moved up in size to a 25/64" twist drill. That delivered what seems like the right resistance when pressing in the metal anchor. And after two days, the wood has not cracked.

The anchor is 0.88" tall (about 7/8") and is supposed to bottom out in its hole. Of course, the twist drill hole is "somewhat vague" in terms of depth and bottom contour. A Forstner bit would render a nice FLAT-bottomed hole, and it's center point would create a pilot hole that would make it easy for me to drill the second smaller hole for pressing the anchor out later on.

I always find it difficult to align a Forstner bit with my center mark. So I thought I'd chuck a very small-diameter bit, align that above my mark, and swap in the 25/64" bit for the actual drilling. But my 25/64" bit is so long that I'd have to lower the drill press table...and that would destroy my setup accuracy. So instead, I thought I might mount a transfer punch (https://www.homedepot.com/p/Stark-Mechanic-s-Center-Punch-Transfer-Tool-Set-28-Piece-13130-H/312425895#:~:text=A%20transfer%20punch%20set%20is, that%20hole%20to%20another%20surface.) in my chuck and align its little end point over my drill mark. Then replace the transfer punch with the 25/64" bit and drill the hole.

I will experiment with my 3/8" Forstner bit. I don't have a 25/64" Forstner bit, but maybe my Forstner 3/8" will cut a slightly larger diameter hole than does my 3/8" twist drill. If the 3/8" Forstner hole creates the correct interference fit, I'm in business(!)

Fingers crossed. =D

Matt Day

11-27-2021, 2:44 PM

Make some test holes in the same wood. I usually use a punch to located the hole so the bit doesn’t wander.

Tom Burgess

11-27-2021, 2:47 PM

I don't know if the pilot hole would cause the larger bit to wander; I do know a small diameter bit is more likely to be deflected by grain in the workpiece than the larger bit would be, so it might be counterproductive for that reason.
Great point. Thanks for thinking through this.

If I need holes to be perfectly positioned, I make a drill guide out of hardwood or better, something like phenolic that has no grain.
If I were a luthier or serious guitar technician I would follow that advice. But this is a one-off (actually two guitars) and budget is a constraint. Thanks for the details; I'm sure they'll come to mind at some later point when I'm fully able to implement them.

Tom Burgess

11-27-2021, 2:53 PM

Make some test holes in the same wood. I usually use a punch to located the hole so the bit doesn’t wander.
I wish I had some scrap basswood, but no dice.

There's an area at the middle of the guitar that's hidden front-and-back by plastic covers (pickguard on the front and backplate on the rear). I've been thinking about using that as my test case, but haven't (so far) as I don't want to be known as a 'wood butcher.' Ha! Actually, nobody but me will ever look in there, and these two guitars will have little to no resale value, despite (hopefully) turning out to be far more playable than anything one can buy off-the-rack in the same price range.

Zachary Hoyt

11-27-2021, 2:54 PM

A 10mm Forstner is so close as to be functionally identical to a 25/64" and may be easier to find/cheaper.

Tom Burgess

11-27-2021, 3:34 PM

For the most accurate work, use metal working tools. Start with an optical center punch. Then if you will use a pointed drill, drill with that. If you use a twist drill, use a center drill.
Thanks for good advice. I sold off my small milling machine two years ago along with most accessories. Been kicking myself ever since.

Never heard of an optical center punch, but found THIS (https://www.youtube.com/watch?v=JtLvEjR0M1w). Interesting and entertaining.

I found a set of very small center drills at Harbor Freight (yeah, budget constraints apply) but they're very small diameters and I fear the tips will break off, even in wood (ha!). Or maybe if I just look at 'em hard.

I appreciate the suggestions, but can't justify the cost of buying real versions. =]

Tom Burgess

11-27-2021, 3:50 PM

A 10mm Forstner is so close as to be functionally identical to a 25/64" and may be easier to find/cheaper.
Good to know. Thanks!

Just did a quick search online, and metric Forstner bits are few and far between. I found a set for $60 that starts with 10mm, and found a single Bosche 10mm for $22. At that rate, first I'll experiment with my 3/8" Forstner bit (it takes special skill to operate a drill press with your fingers crossed). =]

If the 3/8" Forstner bit drills the same size hole as the 3/8" twist drill, that'll be too small. In that case, maybe I'll drill the hole short, to 5/8" depth using the slightly larger 25/64" bit. Then mark the 7/8" depth on the shaft of my 3/8" Forstner bit and finish the bottom of the hole to a depth of 7/8" with that.

The bottom 1/8" of the cylindrical metal anchor is a smaller diameter than the rest of it, so the slightly smaller 3/8" hole bottom won't matter. That would give me a flat hole bottom AND would create a pilot for drilling the small diameter hole necessary for pressing the anchor OUT later.

I really enjoy the way discussion among knowledgeable, enthusiastic people who like to do and make things leads to solutions.

Fingers crossed...

Jim Becker

11-27-2021, 4:22 PM

Given you'll be using a DP and clamping the bassword body to the DP table for the task, you do not really have to drill a pilot, IMHO, if you use a sharp drill bit for the work. I tend to use Forstner bits for this kind of thing. The advise to very carefully mark "the spot" with a center punch is spot-on. It doesn't need to be deep but it will serve as the spot you need to line up your drill bit before clamping and doing the deed. A dimple is easier to do that with than just a pencil mark, IMHO. But again, not deep...just enough to show the spot clearly.

BTW, I've been really happy using basswood for guitar bodies. It cooperates really well and is fine grained. While I cut on my CNC, any hand work with sharp tools subsequent to that work has been a pleasure. The price is pretty decent, too.

Bill Dufour

11-27-2021, 7:17 PM

Tom Burgess

11-27-2021, 7:49 PM

Given you'll be using a DP and clamping the bassword body to the DP table for the task, you do not really have to drill a pilot, IMHO, if you use a sharp drill bit for the work. I tend to use Forstner bits for this kind of thing.
I just tried the 3/8" Forstner in an inconspicuous section of the basswood body. Too tight, so my only option looks to be the 25/64" twist drill.

The advise to very carefully mark "the spot" with a center punch is spot-on. It doesn't need to be deep but it will serve as the spot you need to line up your drill bit before clamping and doing the deed. A dimple is easier to do that with than just a pencil mark, IMHO.
Agreed. In my 3/8" Forstner experiment, I did dimple the center point as you suggest, and was surprised at how easy it was to align the Forstner center spur with that dimpled centerpoint. I guess I've had problems with that because I typically use larger Forstner bits; all that 'diameter' gets in the way of seeing exactly where that spur is in relation to the centerpoint dimple.

BTW, I've been really happy using basswood for guitar bodies. It cooperates really well and is fine grained. While I cut on my CNC, any hand work with sharp tools subsequent to that work has been a pleasure. The price is pretty decent, too.
I bought two inexpensive Chinese Stratocaster clones. Excellent value, but some dimensions are out of spec. For example, I have to slip the bolt-on neck away from the body because the scale length is too short. Can't intonate properly unless I extend the scale length to the correct 25.5 inches.

So I converted the four neck-screw holes to short slots last night. Had everything lined up perfectly, with the body clamped firmly to the drill press table. My 3/16" twist drill entered the workpiece exactly where I intended, right next to each existing 3/16" hole. BUT...when I unclamped and flipped the body/workpiece, those new holes were not aligned properly at their exits. And each wandered in a slightly different direction. Had to clean things up with a coping saw. But as you say, the basswood was easy to work with hand tools.

Tom Burgess

11-27-2021, 7:53 PM

A aircraft type stepped drill would work. But the plot point is not much smaller then the main body portion. Good practice is the pilot should be no larger the the diameter of the web of the bigger drill.
Bill D

https://www.ustoolandfastener.com/3-8-step-drill-bit-kjd/?utm_term=&utm_campaign=ECI+-+Google+Shopping+-+Kreg+Drill+Bits+(Non-Brand)(high)&utm_source=adwords&utm_medium=ppc&hsa_acc=3922278569&hsa_cam=269730264&hsa_grp=19591638864&hsa_ad=88393119144&hsa_src=g&hsa_tgt=pla-275075342534&hsa_kw=&hsa_mt=&hsa_net=adwords&hsa_ver=3&gclid=EAIaIQobChMIybXv8-O59AIVeT2tBh1uzwjtEAQYASABEgLobvD_BwE
That stepped drill (https://www.ustoolandfastener.com/3-8-step-drill-bit-kjd/?utm_term=&utm_campaign=ECI+-+Google+Shopping+-+Kreg+Drill+Bits+(Non-Brand)(high)&utm_source=adwords&utm_medium=ppc&hsa_acc=3922278569&hsa_cam=269730264&hsa_grp=19591638864&hsa_ad=88393119144&hsa_src=g&hsa_tgt=pla-275075342534&hsa_kw=&hsa_mt=&hsa_net=adwords&hsa_ver=3&gclid=EAIaIQobChMIybXv8-O59AIVeT2tBh1uzwjtEAQYASABEgLobvD_BwE) looks great. I've never seen one before, but I see it's part of the Kreg line. I just found out that 3/8" is too small a hole, so thank you, but I'm going to have to go to 25/64" and that's an unusual size. So it looks like a twist drill in that size is my only option.

And thanks for the rule of thumb regarding maximum size for the pilot hole. That'll be a problem for me in this case, because I don't have long bits in small diameters. I hope it's not a hard and fast rule.

Jim Becker

11-27-2021, 8:22 PM

Bummer that the kits had the scale incorrect...that's a bear to adjust when a trem is involved. Hardtail...you could have just moved the bridge. Trem...you gotta do the neck dance and then deal with the gap at the heel.

I encourage you to build your own, too. We have a nice Musical Instrument forum here at SMC where a number of guitars have been featured. I'll also recommend the TDPRI forums, specifically the "Tele Home Depot" discussion area. Nice folks like here with a focus on guitar building, and not just Fender designs. Several of us are members both here at SMC and there at TDPRI.

Kevin Jenness

11-27-2021, 9:17 PM

John K Jordan

11-27-2021, 10:17 PM

I've had good success by starting the holes in wood with either a center bit or a starter bit, both used in machining. This assumes using a drill press to constrain the bits and clamp the work, of course. An x/y table for the drill press can help with precise positioning.

For precision if possible I always use shorter bits rather than long jobber bits. Screw machine bits are perfect - stubby and won't flex. Or you can cut a long bit shorter and resharpen if you have that ability.

A good drill press and chuck with no slop is important if a precise hole size is needed. Even better, if you have or know someone with a milling machine you can make holes as precise as you'll ever get, both in position and hole size. Align the wood with the axis of the work and use the X/Y cranks to position precisely in angle and distance. Can use a center-cutting end mill that will make a plunge cut but a good drill bit held in a collet should be as precise. A quality Jacobs chuck will work too but if hole diameter precision was needed I'd test it with a drill rod and a dial indicator. I use a laser center finder to align the axis with the marked position then swap it out for the bit. I use the laser center finder on my drill press too. I bought this one:
https://littlemachineshop.com/products/product_view.php?ProductID=2604

I don't see you mention where you live - there may be people reading with scrap basswood near you. I keep basswood in 12/4 to 16/4 planks up to 12" wide. (I use it to make woodturnings with chip carving.)

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JKJ

David Buchhauser

11-28-2021, 12:01 AM

For the most accurate work, use metal working tools. Start with an optical center punch. Then if you will use a pointed drill, drill with that. If you use a twist drill, use a center drill.

I agree on the "metal working tools". My first thought (if I were tasked with doing this) would be to fixture this guitar body to the table of my Bridgeport milling machine with digital readout. Then I would either drill, mill, or some combination to produce accurate round holes in the desired locations.
David

Keith Westfall

11-28-2021, 12:31 AM

I just tried the 3/8" Forstner in an inconspicuous section of the basswood body. Too tight, so my only option looks to be the 25/64" twist drill.

I'd drill it with the Fostner bit first and then ream it with the 25 /64. It should/will follow the hole for a clean out, rather then rely on the 25/64 to drill the hole first. Fostner bits don't usually wander to far a stray!

Clint Baxter

11-28-2021, 7:02 AM

It will be more accurate to drill the larger hole first, as it will be less likely to deflect than the smaller drill. It is relatively easy to find the center of the larger hole, even with a twist bit. For a cleaner entry you can get a 25/64" brad point. https://www.leevalley.com/en-us/shop/tools/power-tool-accessories/drill-bits/42247-hss-lipped-imperial-brad-point-drills?item=07J0225

FWIW Lee Valley has brad point bits in both 25/64 and 10mm sizes. They also have a 10mm forstner bit for $10.50, much cheaper than the Bosch bit you referenced in an earlier post. More options to consider.

Clint

Walter Plummer

11-28-2021, 8:11 AM

I just became aware of these bits a while ago. I have not used one yet but I like the idea. The tips are like small step drills to start the bit. https://www.norsemandrill.com/Vortex-Point-Mechanics.php. KBC tools sells them. https://www.kbctools.com/customer/docs/SKUDocs/uOct2021_SaleFlyer.pdf Page 5 of flyer.

ChrisA Edwards

11-28-2021, 9:17 AM

Tom, I have loads of offcuts of basswood, what size pieces do you need?

Basswood is very light in weight.

I'd be happy to send you some for the cost of shipping.

Ole Anderson

11-28-2021, 9:23 AM

Mission critical? Construct a steel drill guide first. That way there is no chance for the drill to follow the grain and wander.

Jim Becker

11-28-2021, 9:29 AM

Mission critical? Construct a steel drill guide first. That way there is no chance for the drill to follow the grain and wander.

"Enquiring Minds" want to know...what that actually is. ;). And it it applicable for use on a drill press like the OP is doing?

Brian Holcombe

11-28-2021, 9:35 AM

A drill guide is helpful if you are doing multiples of this work.

Larry Frank

11-28-2021, 6:54 PM

Amazon has all kinds of 10 mm drill bits. I would use a 1/8" drill bit and then a 10 mm brad point bit. I have done similar many times with very good results.

You can also get some bass wood on Amazon to practice on.

Tom Burgess

11-28-2021, 8:41 PM

Thanks for the helpful, informative replies.

Milling machines (that weigh more than my car, ha) are not an option. I had a small SIEG X3 mill that I sold two years ago. Never thought about using it to work on guitars or other woodworking applications; kicking myself now for selling it.

Thanks to ChrisA Edwards for the offer of basswood scrap pieces, but I'll hold off for now. There's a local woodworker's supply that might stock basswood, but as I understand it, four wood species qualify as "basswood," so your offcuts might not be the same as what was used for this particular body. Thanks a lot, though.

I drilled through a 1" thickness that's hidden by the metal plate behind the bolt-on neck. 3/8" hole was too tight. 25/64" seems about right, though maybe slightly loose. And that brings me to the next variable:

Better the Devil You Know: My 25/64" twist drill makes a hole that seems to work. The excellent brad-point drill by LeeValley, as suggested by Kevin Jenness, might make a slightly different sized hole, And the 10mm drill from the same source, suggested by Clint Baxter, will be a few thousandths larger. I'd like to test with both those bits, but time and money are against it.

I've been studying up on drill geometry and sharpening. There are some significant x-factors(!) The 25/64" twist drill I have is new and sharp, and cuts a hole that feels just about right when I press the metal anchor in, so I'm inclined to use that bit. And I appreciate the point made by several of you, that a pilot hole made by a small bit might wander, so here's what I think I'll do (tell me if I'm wrong):

1. Chuck a 1/4" transfer punch and align it's center point with my punched start hole on the workpiece.
2. Don't move any aspect of my set up.
3. Chuck the 25/64" drill and drill to a depth of 1", which will exit the underside of the guitar body, but in a hidden location.

Why drill all the way through? Turns out there's only .950" of basswood thickness (less than an inch). The metal anchor is .880" long (about 7/8") and should be pressed in slightly below the surface of the guitar body. So the remaining basswood would be paper-thin, that is, IF I could do everything perfectly.

The 25/64" hole diameter might be a tad large (loose), and while I don't find any information stating that the anchor needs a hole with a bottom surface, I think a bottom to the hole makes sense. So...I plan to screw a short length of 1/8" aluminum bar to the basswood underside, hidden from view and hopefully not interfering with the tremolo springs. The aluminum would form a flat bottom for the holes, so the anchors can't work their way down and out.

I had no idea how many issues I'd face in "modifying" this guitar...

=O

Jim Becker

11-28-2021, 8:50 PM

You are going to need a 10mm drill bit for guitar tuners anyway, so I agree with the suggestion to obtain one as well as the other common metric bits. A lot of guitar parts are metric, not Imperial so the bits like the 25/64 are somewhat an approximation.

Bill Dufour

11-28-2021, 10:29 PM

If you can not find the correct metric drill in the configuration desired remember standard twist drills also come in number and letter sizes. All drill bits drill a hole slightly greater in diameter then the bit due to runout of the bit, chuck, drilling machine.
I think a W drill will be closer to 10mm then 25/64
Bill D.

10mm= 0.393701
W = 0.38
25/64 =0.3906

Bill Dufour

11-28-2021, 10:38 PM

Screw machine, screw length drill bits are shorter and less likely to wander.
Bill D

Tom Burgess

11-29-2021, 12:38 AM

Thanks, guys.

Stewart-Macdonald is a well-known retailer of guitar parts and tools. The Stew-Mac product page for the bridge I'm installing says, "use a 3/8" drill for the 2-point post anchors." The best how-to source I found for installing these things, member vid1900 on Stat-Talk.com, says the anchor should press in easily.

I drilled a 3/8" hole in softwood (pine or spruce). It was difficult to press in the anchor, and the softwood cracked when the anchor was about half way in. When I drilled a 3/8" hole in a hidden spot on the basswood guitar body, the anchor felt like it wasn't going in at all. The basswood is harder (or at least more rigid) than the softwood, and I was pretty sure the basswood would crack if I forced it using the drill press as a press ram.

Thanks to you Bill Dufour for suggesting the 'W' size drill. I didn't know it existed, but for basswood, which is prone to splitting in this case, I think the .380" diameter is too small. Slightly larger than .375", but I think still too small; that basswood won't allow much of an interference fit.

The 25/64" twist drill makes a hole that enables pressing in the anchor "easily," requiring moderate pressure. If any problem occurs, it'll be that the 25/64" hole is slightly loose. I don't want to drill too large a hole because I don't know how to reduce it if needed (I read somewhere about wood glue and toilet paper?). But drilling too small a hole will likely crack the skimpy basswood section when pressing in, and that would destroy the guitar. So I think it's better to err on the side of a slightly large hole.

Each anchor is fluted/splined. The outer diameter measures .392", and the lesser diameter—taken at the valleys of opposing splines—looks to be about .384". My 25/64" drill measures .387", so the sides of the wood hole will engage the anchor to about 1/2 the depth of the splines. By the seat of my pants, that sounds like a pretty good fit.

As for metric, a 10mm drill is sure to be larger than the 25/64" drill, and that will be too large a diameter. Also, thanks Jim Becker for suggesting buying a 10mm drill for guitar work in general (and for the guitar tech user forum suggestions in your previous post). I've already replaced the Chinese tuning machines with Fender locking (staggered post heights: 3 high, 3 low) and thankfully the headstocks are drilled for 10mm tuners. Keeping the cost down is a big factor in modding these two "specimens" and I don't intend to do more of this work. So I'll hold off on buying that 10mm drill for now.

I just need two Strats, set up differently for specific applications. The road I'm on seemed like an inexpensive solution, but the "opportunity cost" is mounting way beyond what I anticipated. Live and learn...

Kevin Jenness

11-29-2021, 7:43 AM

I don't want to drill too large a hole because I don't know how to reduce it if needed

Clearly you need to buy a cnc router in order to get the exact size hole you want.

Seriously though, you could sleeve a slightly oversize hole with epoxy. Assuming that the posts are splined in line with their length and need to be removeable you could wax the posts before insertion. Epoxy can be softened with heat if extraction is required. If they have annular rings that is another story.

Anticipating the exact size of a hole in wood based on the nominal dimensions of a boring bit is tricky, especially for a press fit. The accuracy of the bit's manufacture, the density and structure of the wood, runout in your drill press all contribute to the final result. Really the only way I know is to take a guess at the right size bit and try it out. Or dial it in on your cnc machine.

Jim Becker

11-29-2021, 9:20 AM

T
I just need two Strats, set up differently for specific applications. The road I'm on seemed like an inexpensive solution, but the "opportunity cost" is mounting way beyond what I anticipated. Live and learn...

I think that you've discovered the real life risk with inexpensive kits/components. Inconsistency, even from the same vendor. But you still get the satisfaction of setting things up the way you want.

And don't be foolish...it will not be limited to just two S-type instruments. LOL It's like routers and hand planes...you can't have to many. Heck, I can barely play guitar and this happened...with more on the way. (The only one I didn't make is that very old, very cheap nylon acoustic)

468919

Brian Holcombe

11-29-2021, 10:06 AM

.005” is probably very close to where you want to be for a press fit in wood. I would clamp across the grain when pressing also.

Tom Burgess

11-29-2021, 11:33 AM

I don't want to drill too large a hole because I don't know how to reduce it if needed
Clearly you need to buy a cnc router in order to get the exact size hole you want.
Ha! Count me IN!

Seriously though, you could sleeve a slightly oversize hole with epoxy. Assuming that the posts are splined in line with their length and need to be removeable you could wax the posts before insertion. Epoxy can be softened with heat if extraction is required. If they have annular rings that is another story.

I should have included a photo of the metal anchor from the start.

468928

And here's a link to the bridge in question with associated parts, including the anchors (https://www.philadelphialuthiertools.com/bridge-and-tailpieces/tremolos/gotoh-wilkinson-vs-100n-vs100n-2-point-non-locking-tremolo-bridge-chrome/)

I'll look online for more information about lining the hole with epoxy. In the meantime, two quick questions:

Q1. I'll be using J-B Weld (Original Formula) for the first time, to attach an aluminum brace to the interior of the guitar body - intended to support the basswood and keep it from splitting later due to vibrato bar use. The packaging describes J-B Weld as a "Cold-weld two-part epoxy system." Do you know if it would be is suitable for sleeving the hole.

Q2. I assume the epoxy is used to lightly coat the hole. Is the idea to then redrill to intended size, with the epoxy making up the difference?

Anticipating the exact size of a hole in wood based on the nominal dimensions of a boring bit is tricky, especially for a press fit. The accuracy of the bit's manufacture, the density and structure of the wood, runout in your drill press all contribute to the final result. Really the only way I know is to take a guess at the right size bit and try it out. Or dial it in on your cnc machine.
I appreciate your spelling that out, as it corroborates exactly where I am in the process. Sounds like the voice of experience, long-standing in your case, and recently-acquired in mine. =]

CNC? Someday maybe.

Tom Burgess

11-29-2021, 12:01 PM

I think that you've discovered the real life risk with inexpensive kits/components. Inconsistency, even from the same vendor. But you still get the satisfaction of setting things up the way you want.468919

Absolutely. Hard lessons, but as a result, I've learned more about Stratocaster guitars in the past two months than most Strat owners/players will ever know. And yeah, assuming I get everything "just right," these two strat clones will surpass some actual Fender Stratocasters costing many times the money I've invested.

And don't be foolish...it will not be limited to just two S-type instruments. LOL It's like routers and hand planes...you can't have to many. Heck, I can barely play guitar and this happened...with more on the way. (The only one I didn't make is that very old, very cheap nylon acoustic)468919
HA! I hear you, Jim. I've been down that road with other types of projects. They take over your life if you let them. Honestly, I owned one acoustic guitar for decades. That's it, just one guitar. But the ability to record digitally at very little expense opens the Pandora's Box of "needing one more instrument, or one more microphone, etc." Luckily, I proved to myself long ago that more gear seldom solves my problem. More work and practice are the solutions.

I cannot see your photo because I'm not a supporting member at this time. I assume it's brimming with guitars in your collection, most of which you built. The ability to build inexpensive instruments that compare well with very expensive (way overpriced) big-name instruments makes it very difficult to resist building an expansive collection. Brother, there should be a 12-step program... =]

I have two acoustic guitars, setup differently for specific purposes
I have a short-scale, single-cutaway solid body electric with a pair of humbucker pickups (coil split) to fill the role of a Les Paul
I have a five-string bass
I will have one Strat clone with a floating tremolo bridge, for traditional Stratocaster work
I will have one Strat clone with a decked tremolo (easily converted back to floating), for bending strings and imitating Telecaster tone

THAT'S IT!
THAT'S ALL!
I hope... =D

Tom Burgess

11-29-2021, 12:05 PM

.005” is probably very close to where you want to be for a press fit in wood. I would clamp across the grain when pressing also.
There's some built-in inaccuracy, but I think my measurements suggest about a .005" press fit. So I take your remarks as a confirmation and encouragement (tell me if I'm wrong).

Clamping across the grain is a great idea, but the guitar's shape makes it difficult, and being a very inexpensive specimen, the paint wants to chip off if I just look at it hard. I'll see if I can find a way. Thanks

[AFTERTHOUGHT] I expect to install the aluminum brace described in my Post #40 above before I drill the two dreaded post holes. That brace should negate the need for cross-grain clamping.

As your signature implies, I'm about to "bumble forward into this unknown."

Jim Becker

11-29-2021, 12:58 PM

I cannot see your photo because I'm not a supporting member at this time.

Easily fixed...Click on the Donate button up above. $6. ;) Well worth it as you get photos, private messages, Classifieds, etc.

Kevin Jenness

11-29-2021, 3:12 PM

Q1. I'll be using J-B Weld (Original Formula) for the first time, to attach an aluminum brace to the interior of the guitar body - intended to support the basswood and keep it from splitting later due to vibrato bar use. The packaging describes J-B Weld as a "Cold-weld two-part epoxy system." Do you know if it would be is suitable for sleeving the hole.

Q2. I assume the epoxy is used to lightly coat the hole. Is the idea to then redrill to intended size, with the epoxy making up the difference?.

I don't think I'd use JB Weld for either application as it is a putty consistency and won't penetrate the wood to any degree. I use marine epoxy to wet out the wood and thicken it with various fillers when needed.

As to sleeving, I would coat the hole with epoxy and set the pins wet. Do a test to see if it will work for you. If you can get a proper press fit by drilling that would be preferable.

Tom Burgess

11-29-2021, 3:33 PM

Easily fixed...Click on the Donate button up above. $6. ;) Well worth it as you get photos, private messages, Classifieds, etc.
SIX BUX?!

=O That's amazingly inexpensive. SawmillCreek.org has always been a great source of woodworking information, well worth supporting. And yeah, the benefits you outline are indeed worthwhile.

Now that I'm relocated, and have decent garage space again, maybe I can return to my natural DIY ways. I sold off my bench tools prior to the interstate move, and have been working on my new/old fixer-upper house for the past year. Things are finally pretty much under control, so I WILL join as a supporting member, but will put that off until after January 1. It'll be a business expense, and I want to keep bookkeeping organized...or at least try.

I'm trying to complete this project using only what I have on hand. Had to purchase a few specialty items for drilling in tight spaces (inside the body), but that's about all. I put together a clamping jig (out of scrap wood and a couple of carriage bolts) for mounting the guitar body on the drill press table. Man, without that, these operations are impossible. Next step is to run E and e strings from the loose bridge (set in place) to their respective tuning machines. I know you know this, Jim, but for others I'll explain that adding the strings helps me judge the space between outer strings and the edges of the fretboard. Sort of a "second opinion" to help me center the bridge relative to the neck.

Then...gulp...it's down to marking the two actual drilling points, and going for it...

Tom Burgess

11-29-2021, 3:49 PM

I don't think I'd use JB Weld for either application as it is a putty consistency and won't penetrate the wood to any degree. I use marine epoxy to wet out the wood and thicken it with various fillers when needed.

I'm trying to use what I have on hand, or keep my methods as inexpensive and simple as possible. I take your point, but this YouTube link (https://youtu.be/XQ6THQM0Qg0?t=296) makes me think J-B Weld is sufficient for installing my aluminum anti-split brace.

As to sleeving, I would coat the hole with epoxy and set the pins wet. Do a test to see if it will work for you. If you can get a proper press fit by drilling that would be preferable.
I much appreciate this insight, Kevin, and will keep it in mind, but I'm afraid =O of setting these anchors in wet epoxy. I have very little experience with 2-part epoxies, but a healthy respect for their holding strength. I read somewhere that heat can be applied to the threaded posts via a soldering iron, and the heat should transfer to the anchors sufficiently to remove the anchors if need be. But Murphy's Law never sleeps, and it's possible that I will need to remove the anchors for maintenance or to relocate these bridges to better guitars one day.

Fingers crossed that the 25/64" drill does the job without complications.

Kevin Jenness

11-29-2021, 5:10 PM

I suppose if you can't get a drilled hole the right size you could sand down the anchors a bit.

Epoxy is expensive but it has many applications in woodworking and a very long shelf life.

Larry Edgerton

11-30-2021, 7:35 AM

I start holes that need to be perfect in wood by first reversing the drill press. By reversing it to get the hole center started it will not bend the bit and follow the grain. Before I had a reversible drill press I kept some left hand bits around for the purpose.

Jim Becker

11-30-2021, 9:08 AM

I suppose if you can't get a drilled hole the right size you could sand down the anchors a bit.

The downside here is that these inserts need the grip of the texturing since they do not get glued in and one has to be very careful not to overshoot since they can be expensive to replace. In some cases, that means buying a whole new bridge for the guitar because parts a la carté are not necessarily a thing.

Keith Outten

11-30-2021, 11:49 AM

https://lasercenteredgefinder.com/

This is the answer to drilling perfectly centered holes on a drill press. I use mine on my drill press and CNC Router but it can be used for a lot of tasks and its about as easy a method as you will find. Once you set the dot on the center of your hole from your chuck change to your drill bit you will never wonder if the hole will be in the right location.

The diameter of the red dot is adjustable by turning the knurled collet.

It's worth every penny!!!!

Edward Weber

11-30-2021, 2:27 PM

My method would be a little less complicated than some others.
Make your own drill guide block from a piece of hardwood.
Test drill, adjust, tweak or whatever you need to do on a sacrificial piece until you get the proper fit for the bridge. Once this is done, you can use the guide, clamped or double-stick taped to the body, to drill the holes without worry of wandering.

Or you could just purchase a bridge drilling guide.
Good Luck

Tom M King

12-05-2021, 6:09 PM

If you use epoxy, use golf club head epoxy. It's available in small quantities. The good thing about it is that it breaks down at a lower heat than most other epoxies, since you're thinking about removing it in the future. It breaks down at a low heat so you can remove a golf club head from an epoxy shaft, without damaging the shaft (if you know what you're doing).

When you need to remove the insert, set with such an epoxy, thread a bolt into the insert, and heat the bolt until the epoxy starts to bubble out. Then it will come right out.

Anuj Prateek

12-05-2021, 11:26 PM

I would suggest using a router. A jig will be needed to position the router correctly. Post that order of bit won't matter.

David Buchhauser

12-05-2021, 11:33 PM

There are many good suggestions here. Many different approaches to achieving the same end result. Lots of great input!
David

Mike Henderson

12-06-2021, 1:04 PM