#1
Hello

I have an Aria Pro CS-350 (front body pic can be found on my profile).

A couple of the tuning machines slip and I would like to replace them, but I have never bought machine heads and I feel ignorant as to what to look for when buying new machine heads. I was also wondering if anybody knows how the measurements for machine head holes go, like how can I find the measurements for my current machine heads so that I know what replacement heads to buy that, would allow me the least amount of drilling new holes?

I have tried getting replacement parts from aria guitars, but my guitar was made in 1981 and they no longer sell parts for it.

The machine heads look very similar to the heads on an Epiphone G-400. ("half moon" shaped keys and the backs are shaped like the letter D with the center filled in.

As you can probably tell I am new to the realm of DIY guitar work in general, and any help you can give me would be greatly appreciated.
#3
It could well be your tuners, but without wanting to sound condescending, are you stringing up correctly?

Anyway, choosing tuners is easy, go for a named brand. Schaller are very good, Grovers are good, I like Gotoh (510 specifically).

You could also get locking tuners. These clamp the string, then you just wind them a touch to tune up.

Remove one of your tuners and measure the diameter of the hole in the headstock, it may be a 10mm hole it may be an Imperial measurement, so see which is nearest or google it.

They may be 11/32 inch. So if they are and you want 10mmm tuners, then the holes have to be made bigger.
People seem to make a big deal about this and possibly for good reason. Some say it is a bad idea to even use a drill press (rather than hand drill) and you should use a reamer to do it. The reamer will centralise the hole and I should think you would do it from both sides. screw mac sell a reamer for this but it will cost more than the tuners




That is a Gotoh 510, very sexy and uber reliable.

This one is a Schaller, locking tuner. The knurled nut is what you use to lock the string.



Have a look on ebay etc for tuners and see what you can find.
Quote by Cal UK

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Last edited by Skeet UK at Jan 2, 2010,
#4
I would bring the guitar into the store and say you need new tuners, but you have no idea what size, etc.

I'd suggest everything the post above me did, and I'll add Spertzels (spelling?) to that list.
#5
Thanks everyone for the help. SkeetUK your response was excellent, and answered all of my questions. Also I will have to look into the reamer thanks for the suggestion. Again, I would like to thank everyone for their help and time.
#6
Quote by TonTon1981
Thanks everyone for the help. SkeetUK your response was excellent, and answered all of my questions. Also I will have to look into the reamer thanks for the suggestion. Again, I would like to thank everyone for their help and time.


As Mr Collins concurs that it may not be your Tuners, I will add this pic and link about stringing up.

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How to string up and nice anecdote.

Obviously, locking tuners will save you any trouble with regards to how it's all wrapped.

The reamers are stupidly expensive. I'm not sure what Mr Collins would suggest, but if you do need to enlarge the holes and can jig up a drill press, you should be able to do it. I wouldn't use anything less than a drill press though. You should be able to get a regular reamer, not from StewMac that will do the job for about 1/30th of the price (I kid you not).

I guess that this subject is something that could possibly involve more than the avergae Joe would imagine. I would be interested in how Mr Collins would approach this and if he can offer any advice, as I want to change out some tuners on one of my instruments.
Quote by Cal UK

...that's what Skeet always says anyway and he's a sex god.


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#7
Quote by David Collins
If you do want to replace the tuners, and have to enlarge the holes, a reamer is the proper tool for this. People may sometimes use a drill bit in a press or hand drill and make it out unscathed, but it's a risky endeavor, and you can stand serious risk of pulling chips or blowing out the back side.

Though their taper is a bit steeper than ideal, and their fully fluted design can make centering a bit more of a challenge, a general reamer from your hardware store can work fine for this. I use straight reamers for fitting a lot of tuners, but if you are careful, go slowly, and don't go too far, a general use tapered reamer can get you by just fine.



So a straight reamer would have a slight lead, with the majority being straight (one diameter)?

With a tapered reamer, would you work from both sides of the hole?
What would the correct process be?

I must say, it is so nice to have a helpful expert around, Mr Collins
Quote by Cal UK

...that's what Skeet always says anyway and he's a sex god.


Member of the official GB&C "Who to Listen to" list


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#8
Thanks again everyone. I can actually see the stripped gear inside a couple of my machine heads so I am pretty sure I will need to replace them, but I will keep in mind all of the other potential issues that may stem from the machine heads. Thank you all again very much. You have all been a great help.
#9
Quote by David Collins
Thanks! Straight reamers will have not so much a lead, or taper at the end, but rather just a slight bevel at the end of a straight cutter. They can have either straight or spiraled flutes, as can different specialty drill bits, but what distinguishes one from the other is that drill bits have the cutting face on the end, whereas reamers cut only on the sides of the flutes. I'm sure this is something you already know just by looking at them, but thinking consciously about how tools work differently can be key to choosing the right tool for the job.

If you have a cutting edge on the end of a spiral drill bit, I feel this is best thought of as a chisel wrapped in a spiral around a shaft. When enlarging a hole, you are only cutting on an edge, which essentially leaves it to act as a screw. The cutting edge starts in on a steep angle, it wants to screw right in to the hole, pushing everything aside on either edge of the "thread", rather than chiseling off a smooth continuous layer as it is fed through. It can be done, but it takes a great amount of control of the feed to make it act as a drill rather than a screw. This is of course why there is so much risk of pulling out chips on the entry face, or blowing out and splintering the back side.

Reamers on the other hand, are more like the tip of a chisel or scraper mounted parallel to a shaft. It works more like little elves inside the hole cutting around the circumference, rather than down in to it. Sounds a bit silly, I know, but I've always felt an acute understanding of how each tool is designed to work can help make the reason for their design more self-evident, and choice of appropriate tools more intuitive. Cutting around the hole, directly against the sides will yield a much cleaner hole, and without the tendency to pull through as a drill bit cutting down in to it would.

Drill bits are made for creating holes, reamers are made for enlarging them.

Straight reamers are typically made for machinists, metal work, and are designed to enlarge a hole from a few thousandths, to maybe as much as 1/16" at a time in softer materials.

I probably have at least $1000 in reamers in my shop, from straight reamers of all diameters to tapers of all sorts, so perhaps I'm a bit spoiled there. If you have a 2-3° reamer, or even as much as 5°, you can often do all the reaming from the back, and by the time it is enlarged enough to fit the sleeve on the casing, the bushing will fit in fine from the top. If you get much steeper though, you can end up having to enlarge the back side further than ideal by the time you open the face enough to accept the threaded bushing. So yes, with a 6-7° reamer you'll find in most hardware stores, it can be best to come at it from both sides.


Cheers Mr Collins.

I come from an engineering background of sorts. My father used to build Startrite Bandsaws, mainly the enormous ones, amongst other things and way back when I was at school, I did a fair bit of engineering. Once made myself a scale model of Rover V8 Block out of ali...most look around for that some time!

I was thinking of getting these

Reamer

Not the stewmac ones, but then...not even close with regards to price, but will be very good quality from that store.

Nice to have an idea of the process. I thought that reamers would be best, especially with a set or neck through guitar. I think one would cry, if one were to snap the headstock while not supporting it well enough on a pillar drill
Quote by Cal UK

...that's what Skeet always says anyway and he's a sex god.


Member of the official GB&C "Who to Listen to" list


I support Shay van Fani
I can supply WD Music, ABM and AllParts products to UK builders at DISCOUNTED prices!