My experience installing an under-saddle pickup - OOPS!

I decided that I would install an under-saddle pickup in my KPK tenor uke. The ability to amplify the uke for performance was secondary. What I really wanted was a pickup with a preamp that had a built-in tuner. This way, I wouldn't need to carry a tuner with me. One less thing to keep up with. I found one on eBay that is used on many production ukes for $18 with free shipping. I didn't expect much, but was pleasantly surprised when it arrived.

Step 1: Remove the strings.

Step 2: install the preamp. I made a paper template of the preamp. This is the type of preamp that mounts in the side of the uke and has volume, bass, and treble controls, along with the display for the tuner. I was going to have to cut a rectangle in the side of the uke for installation.

I taped off the area where the preamp was going so as not to scratch the uke. The tape would also help prevent any splintering or cracking of the uke. I then taped the template into place. I used a small spiral drill bit and drilled a hole in the area for the preamp. I progressively enlarged the hole with bigger bits until the hole was large enought for the blade of my jigsaw. Following the template, I made the cutout for the preamp. I made the hole slightly smaller than needed and used sandpaper to enlarge it to the proper size. This was important because hole size had to be perfect. All went well. Step 1 successfully completed.

Step 2: install the pickup under the saddle. After making measurements, I determined that I couldn't just shave down the saddle as I had hoped. If I did, the saddle would no longer fit in the bridge properly. I went to Plan B which was to use a Radio Shack piezo transducer rather than the under-saddle pickup. Many people have installed these to use a passive pickups. The plan was to install a plug on it and plug it into the preamp. I would mount it to the underside of the soundboard using double-sided foam tape. I confirmed that this would work by hooking everything up and holding the RS piezo on top of the uke and found the spot that gave the best sound. I then mounted the piezo in that location, but on the bottom side of the soundboard.

Step 3: Here is where it all went to hell. This should have been the easiest step, but turned into a nightmare. All I had to do was drill a hole for the 1/4" jack for the cable. The hole would be a rather large 3/8" hole. I planned to use a spade type of wood bit to drill this hole. However, I couldn't find the bit that I needed. No problem. I would just use spiral bits.

I knew that I should start with a small bit and gradually enlarge the hole because the wood is so thin. Be an impatient moron, I decided that I could just start out with the 3/8" bit if I went really slow. So I started drilling and was going very slow. Suddenly, the bit punched through the wood. The sides of the bit grabbed and forcefully pulled the bit into the wood, tearing the wood rather than cutting it. The result was that my uke was split open on the side. The splt was about 8" long. I was mortified!

Looking on the bright side, I figured this would give me an opportunity to learn how to repair cracks. I searched YouTube and found instructional videos on how to repair cracks using cleats. Following this instructions, I glued up the crack and installed two cleats. It turned out fairly well and was not too difficult.

I waited a couple of days to make sure the glue was good and dry before restringing. This was very very nerve-racking. I fully expected the tension of the strings to rip the uke apart making it beyond repair. Much to my surprise, the repairs held and I was able to get it strung.

I went to test it and was disappointed when I couldn't get any sound out of the pickup. A little troubleshooting revealed that the piezo wasn't working. Apparently, I pulled a wire loose from the plug during installation. I removed the piezo and was getting ready to resolder the wire when I had an idea. I thought that rather than use this piezo, maybe I could tape the under-saddle pickup to the bottom of the soundboard instead. I gave it a try and was very pleased with the result. It is not nearly as quacky as the RS piezo. Running it through a Behringer preamp/direct box, it has a very nice, natural sound.

All in all, I'm very pleased with the results. Would I do it again? Not with a nice uke. I would practice on an inexpensive one first. Since this one is my beater anyway, I'm satisfied.

Thanks for sharing your experiences. (I have a KPK I want to put a pickup in too)

spoupard said:

Step 3: Here is where it all went to hell. This should have been the easiest step, but turned into a nightmare. All I had to do was drill a hole for the 1/4" jack for the cable. The hole would be a rather large 3/8" hole. I planned to use a spade type of wood bit to drill this hole. However, I couldn't find the bit that I needed. No problem. I would just use spiral bits.

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Thanks for the writeup. I'm considering installing a Mi-Si pickup on my Pono. I thought Step 3 would be easy, but after reading about your experience & one other negative experience resulting in tear out, I'm having second thoughts. Should I drill a small pilot hole first & then use a Brad point drill bit for the full size hole? I have a step drill, & I saw one used in a video on YouTube. Would the step drill be better than the Brad point? Finally, what about drill speed, i.e., low or high speed?

Based on my experience, I'm not the one to ask. However, I would think that a step bit might be ok. I was using a brad point. That didn't work too well. I think a spade type of bit would work well. Normally, you use wood bits at a fairly low speed.

My Pono already has a pickup, but if I was installing one in it, I think I would take it to a repairman/luthier and get them to drill that hole. I would still do the rest of the work, though. It shouldn't cost too much just together that hole drilled.

spoupard said:

My Pono already has a pickup, ---

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What pickup is installed on your Pono AT, & do you like its sound?

bildio said:

What pickup is installed on your Pono AT, & do you like its sound?

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It has the Pono factory pickup. It is a passive pickup. Like it a lot.

Drill a 1/8" pilot hole first then use a 1/2" Step Drill and always drill slowly. You can drill all the way through with the 1/2" step drill to install the 1/4" Jack.

Never push the drill, let the drill bit do the work.

Wouldn't a tapered reamer be the best way to get that hole in there?

Since discovering them a few years ago in my bicycle building hobby, I use step drills almost exclusively now. They almost never grab anything from steel to wood because they use a different technology than spiral drills. Spiral drills cut from the top and side. Each of the spirals is a cutter just waiting to grab the material and either jerk it loose or split it. A step drill, on the other hand is like a bunch of tiny little planes moving around in a circle and cutting from the top - in my experience they just don't tend to grab. When I did my tenor pickup installation, I used a small 1/16 or 1/8" spiral drill for the pilot hole, then a step drill and it went like butter.

You can buy very expensive step drills. I just buy the cheap titanium ones they have on sale all the time at Harbor Freight all the time and have never broken one or had it get so dull it wont drill. They are so cheap, I have several spares.

http://www.harborfreight.com/3-piece-titanium-nitride-coated-high-speed-steel-step-drills-91616.html

Sorry if I'm sounding like a sicko but could you upload some pics. It's always nice to see someone else muck up for a change!

whatevershebringswesing said:

Sorry if I'm sounding like a sicko but could you upload some pics. It's always nice to see someone else muck up for a change!

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I can take photos of the finished product, but I don't have any of it before fixing the split. However, I'm out of town right now and don't have that uke with me. You can't really tell from the outside, though. The crack went back together rather nicely.

SweetWaterBlue said:

Since discovering them a few years ago in my bicycle building hobby, I use step drills almost exclusively now. They almost never grab anything from steel to wood because they use a different technology than spiral drills. Spiral drills cut from the top and side. Each of the spirals is a cutter just waiting to grab the material and either jerk it loose or split it. A step drill, on the other hand is like a bunch of tiny little planes moving around in a circle and cutting from the top - in my experience they just don't tend to grab. When I did my tenor pickup installation, I used a small 1/16 or 1/8" spiral drill for the pilot hole, then a step drill and it went like butter.

You can buy very expensive step drills. I just buy the cheap titanium ones they have on sale all the time at Harbor Freight all the time and have never broken one or had it get so dull it wont drill. They are so cheap, I have several spares.

http://www.harborfreight.com/3-piece-titanium-nitride-coated-high-speed-steel-step-drills-91616.html

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Thanks for the suggestion. I will be picking these up real soon.

I drill the hole by hand when I do it:

http://www.ukuleleunderground.com/f...0-Electrify-your-uke-for-under-10-bucks/page2

"Now I picked the spot for mounting the jack and reamed that
hole out first with a lockblade knife. After that I started using
drill bits turning them only with my fingers one size at a time,
until the jack fit nicely. I don't remember the exact bit size that
worked, but it was one size shy of 3/8". I hand turned the drill bits
in small increments so as not to split the wood"

Thanks for sharing your experience, Scott. It's always best to learn on a beater. Now you also have experience in instrument repair.

The problem was that you used a standard twist bit which has a rake angle designed for self feeding into ferrous metals. For drilling brass, plexiglas, or wood, you should grind the tips of the flutes to a zero rake angle or you are guaranteed to have the bit bust through and grab the work and either injure you or what you're working on. The thing is that almost NOBODY knows this except old time machinists. I've ground nearly every twist drill bit in my shop to be safe for these materials, and I keep a separate drill index for steel and iron.

You can Google this... Try "Zero Rake Angle Drill Bits" or "Modifying drill bits for brass".

I have absolutely no problem going directly to a 1/2" bit to open up an end pin hole. I've done it hundreds of times with modified bits with no problem.

This is why you should keep us old farts around...

I've been using Forstner bits to drill on the CBG's I've building. Work quite well on flat surfaces and make nice holes without splintering.

You can't use Forstners where there's already a hole for a strap button. Learn how to grind the flutes for zero rake, and you can just use a standard twist bit.

Rick Turner said:

The problem was that you used a standard twist bit which has a rake angle designed for self feeding into ferrous metals. For drilling brass, plexiglas, or wood, you should grind the tips of the flutes to a zero rake angle or you are guaranteed to have the bit bust through and grab the work and either injure you or what you're working on. The thing is that almost NOBODY knows this except old time machinists. I've ground nearly every twist drill bit in my shop to be safe for these materials, and I keep a separate drill index for steel and iron.

You can Google this... Try "Zero Rake Angle Drill Bits" or "Modifying drill bits for brass".

I have absolutely no problem going directly to a 1/2" bit to open up an end pin hole. I've done it hundreds of times with modified bits with no problem.

This is why you should keep us old farts around...

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Thanks for the advice, Rick. I'll check it out.

Oh man, that nightmare we have when thinking of doing this ourselves, it totally happened to you. I'm glad you were able to fix it though. I can't even cut straight with scissors.