Drill Zumsteel Neck for Splits? [update 2012]

[Jerry Overstreet]

Any way to work this neck for split tuning screws? This one is before the removable block in front of the changer. It's a solid neck that wraps around the changer.

Looking down on it, it appears the changer mount? [right underneath the eraser] would be right in the way of any stop screws. I might be able to take the neck off and have it worked if not for that.

Anyone taken one apart around '81,82 vintage and would be kind enough to tell me what's under there? If anyone knows for sure, I'd like to hear from you. I know all about splits with rods, but I'd like to do several of those without all the hardware.

[Bob Knight]

JO,
It appears that they would have to be drilled at an angle, which would take the right machinery and skill.

Bob

[Jack Stoner]

My Franklin had two screws added for the 5th and 6th strings. The screws had to be very close to the top of the cabinet. My Franklin is an earlier design and the neck is "split" like the old Emmons PP "split tail" models. I have Mr Franklin do mine but he had to remove the block to drill and thread the holes for the screws. It's tight between the screws and the changer fingers but there is enough room to change strings.

I can't say on this design but I've some that "wrap around" the neck and the back piece just covers the actual block at the back of the changer mountings. In those cases the neck was just cutout to allow access to the block and the screws mounted in the block.

Anyway you go it's going to take removing parts to do it. Call Bruce and see what he says.

You can also do the splits with an additonal pull rod.

Here is how my Franklin was done.

[Earnest Bovine]

You can also do the splits with an additonal pull rod.

I suggest that you first try to accomplish your setup with more pull rods, before you drill holes which might not work well.

[Jerry Overstreet]

I know all about splits with rods, but I'd like to do several of those without all the hardware.

I appreciate what you're saying Jack and Earnest. I have split rods already, but I'm wanting to do some other things and using several rods in this method would add extra weight, clutter etc. that I don't want.

I'm going to disassemble the guitar anyway at some future date to resurface the necks, and generally service this guitar so I'll see what's under there then. I was just hoping someone had traveled this path of adding split screws on this particular model guitar before me.

[tom anderson]

I would send it to Bruce for him to do it.

[Robert Parent]

Jerry,

I added the splits to a similar vintage Zum guitar about ten years ago. Under the neck there was a rough casting which is what I drilled for holding the split adjusting screws. The neck I just notched out so one could get the the screws. You really need a milling machine unless you have lots of time on your hands.

It was a fair job taking everything apart but not all that difficult. The only gotcha was that when drilling the holes in the casting I hit a very hard piece of something in the casting. After breaking untold number of bits I ended up not getting the hole drilled for one string. If I were doing it today I would make sure that there was a carbide drill in the drawer.

Robert

[Jerry Overstreet]

Hey Thanxalot Robert! That's just the info I am looking for. This will give me an idea what to expect. 'Preciate the tip about the carbide bits too.

So would you say it was worth all the trouble?

Yeah, I have relatives and friends that do machine work, so they should be able to handle the milling, drilling, threading etc. no problem. Actually, I have a tapping table myself. I can measure and mark it all, disassemble it and take the necessary parts to the shop.

I'm going to do it when I do the major service job on it. Probably both necks for symmetry and I do use a split or 2 on the C neck as well.

Thanks again.

[Stu Schulman]

Jerry,If you decide to drill it yourself could you post some photos?

[Jerry Overstreet]

Yes I will Stu, but I don't have the equipment or experience to do the machine work. My cuz is a machinist, so I'll have him do the precision work. I might end up tapping the threads after drilling, otherwise it'll just be R and I and the fine tuning for me.

[Stu Schulman]

Jerry,I have no mechanical skills,and am an embarrassment to my family because my dad was a mechanist I am fascinated by this kind of thing.

[Paddy Long]

Jerry the later Zum's have the holes drilled in the wrap around neck ..perhaps you should just contact Bruce and get a replacement later model neck ???

[Jerry Overstreet]

Yes Paddy I know, but there is a casting underneath the neck that has to be worked as per Robert's reply. Replacing the neck wouldn't solve that problem. Anyhow, I don't think it requires a new neck. With proper measuring and marking, any competent machine shop, as BK alluded to, should be able to handle the project for a lot less expense than purchasing 2 new necks.

Thanks to all for your response.

[Don E. Curtis]

Joan Herndon Cox did it to her older Zum...looks real nice, but yes, it was a pro machinist that did it. It can be done.
Good Luck!
Don E.

[Jerry Overstreet]

Thanks for the encouragement Don. Maybe I'll play as well as Joan when I get 'er done! Not! Maybe half as good even.

[Robert Parent]

Jerry,

I think the modification was worth it.... It's very likely you will not run into the drilling issue I did but I posted it as an upfront warning.

You are correct, a modified neck only will not get you the results you are after. That Zum looks exactly like the one I did and you will have to deal with that casting for best results.

Good luck,
Robert

[richard burton]

Here's an off-the-wall suggestion:

Take the helper spring off the finger (I think Zums use helper springs) and attach a rod to the hole where the helper spring was hooked.

Run the rod down the length of the steel, until you have some clear space.

Mount a bracket (to act as a stop) in this clear space, and screw a nylon tuner onto the end of the rod.

You can now use this nylon tuner to precisely control the distance the finger moves when you activate the lower.

[Martin Weenick]

Jerry, I cant tell how far down the string pins are from the picture but if you were to drill low on the back of the changer would a #6 or #8 machine screw come out under the pin ? If not maybe you could drill just slightly off center above where the pin is and let the screw rest on the finger just to the side of the string. Martin.

[Jerry Overstreet]

Thanks for all the ideas fellows. Martin, Actually there is ample room for the screws underneath the pins, it just entails dealing with that casting as Robert mentioned.

It would be possible to drill above the pins as you refer, but it would be precarious as there is no room for error. The thickness at that point, bypassing the casting, is 1/8 to 3/16 and the width about 1/2" so by the time it was drilled and tapped, there's almost no structural integrity and it would have to be a tiny screw.

I've decided to follow the method Robert used if and when I do it. I thought I might resurface the necks, install new fretboards and do some cleaning and polishing in the not too distant future. It'll be some time coming though, so I've got plenty of time to think about it. Thanks all.

[Tony Glassman]

Would you have enough room to skim over the top of the casting if you used a 10-32 set-screw rather than a socket-cap screw?

You could drill higher up on the rear end of the neck, if you didn't need to have room for that socket-cap head.

[Martin Weenick]

I cant imagine what Robert hit with his drill bit in the casting unless he drilled the holes while the changer was still mounted to the guitar and hit one of the screws coming up from the bottom of the guitar that holds the changer on. I use stainless #10 machine screws to hold my changers on and hitting one of those would be a real problem. I dont know if Roberts guitar uses stainless screws or not. There should be no "hard spots" in the casting. This really is an easy job if the changer houseing is removed. I drill these split holes on most every guitar I build. I drill 10 split holes in all my guitars but you only have to drill what you will use yourself. Martin.

[Jerry Overstreet]

Tony, the neck thickness, at that area as mentioned above, is too narrow for any drilling or machine work. Besides, having the screws above the pins is a big hassle changing strings etc. No, they definitely need to go under the pins. The screw heads don't necessarily have to hide in the neck recess, but it would look neater that way.

I won't do anything until/unless I do some major disassembly. It appears to me that the changer pillow blocks are sitting on and attached to that casting. There are probably some mounting screws under there also as Martin alludes to.

I'm not about to ruin a perfectly good and highly desirable instrument. Whether I decide to keep or sell the guitar, I would still want it to look like it was part of the original design. Even though some builders only work the neck for splits on certain strings, I'd want mine to be symmetrical and appear complete. I have done enough cobbling in the past to know when to call in the experts.

Some careful planning, precise measuring and transferring is definitely called for.

When this project is finished, I'm going to start cogitating on how to accomplish changer end splits on a Sierra Crown Not! I don't think I'm up to that challenge

[Jerry Overstreet]

To follow up on this topic for the annals, and for anyone else searching for information on the procedure:

I did it! Well, I did part of it. The drilling, tapping etc. for the split screws was already done but I didn't know that because the neck wraps around and over the changer. Imagine my surprise when I unbolted the necks and saw this was already completed.


Just needed to notch out the necks:


Acquire and install some 6-32 stainless steel screws:


Then pull out all the pull rods I'd been using for splits.

I don't know how many older Zums were worked like this, but I'm really glad this was already completed on mine.

I was taking the guitar down for several things, obviously changer clean-up and servicing being one of them, and I was happy to forego the machine shop work.