finish cracking

[fourdogslong]

Hi, I recently received my warmoth body and neck and I am slowly assembling it, it looks great I can't wait to play it loud!

While I installed a strap button I accidently didn't use the right drill bit and when I put the screw in the hole I drilled (the hole was too small I guess) a thin layer of wood, including the finish over it, poped-up (like a little mountain) which craked the finish a little bit.
With the strap button installed it doesn't show at all but I was wondering if I should put a little bit of varnish (clear coat) where the finish craked or if I should leave it like that, to prevent it from craking more...?

Please let me know what you think, I want that guitar to stay in shape for all my life.
Also, any tip for choosing the right drill bit? Next step for me is to install the pickup ring and I really want to make sure that I don't crack the finish there.
Thanks

 

[Cagey]

Don't pick at scabs. Not that this will ever heal, but you can make it worse. Besides, how often do you suppose you're going to be removing your strap pegs? Twice in twenty years, maybe? Try not to worry about it. If they're mounted and tight and there's no visible damage, call it a love story.

As for bits, if you're just assembling parts, I can't think of anything you'd need to be any more special than your typical twist drill bit. The only time I use anything else for is when I put threaded inserts in the neck - then I use a Forstner bit. But, that's not part of a typical assembly and even there a twist drill would work. I just use the Forstners because they drill very clean-sided flat-bottomed holes and I happen to have them, along with a drill press.

Wood vs. tool steel is no contest. It's butter vs. hot knife. Most of what you have to be concerned with is shredding, and bits have to be pretty bad off before that sort of thing starts happening.

That said, if you only have one set of bits, you might be tempted to use them for everything. In that case, they may dull up a lot earlier than you expect. But, just look at your results. If your holes are getting torn up or they look too fuzzy, it's time for a new bit.

 

[fourdogslong]

I continued to asemble the guitar and I tried to be more careful with my drilling. The holes I drill are now clean but when I insert the screws the finish tends to pop up a little bit arround the hole. Maybe that's because I use drill bits that are too small for the screw.... but to me it really seems like the screw wouldn't bite enough if I used bigger bits. I guess that's the way it is...
Anyway, the final result looks good once the hardware is on place.

Thanks for the tips.

 

[Cagey]

Wood is somewhat compressible, while finishes usually aren't. When you run the screw in, you're displacing wood to make threads. You can expect to see some rise in the surrounding area, but it shouldn't be much. While the hole does need to be smaller than the screw, we're really talking about being smaller than the OD (outside diameter) of the threads, not the shank. Barring some way of measuring it, you can always just hold the bit in front of the screw, and you shouldn't be able to see the body of screw at all; just the threads. Try to be any tighter than that, and you're asking for trouble. In hard woods such as maple, it's not unusual to twist the head right off the screw if the hole's too small. Guys do it with tuning lug locators all the time.

If you're gonna lose sleep over the finish bloom, you can always go up 3 or 4 sizes in bit diameter, chuck that into a tap handle, and just give it one or two turns by hand in the hole once it's drilled. That'll ream the entry edge enough that it's unlikely threading the screw in will create any new chips.

 

[Steve St.Laurent]

Or just by a countersink tool and open up the finish on top.  You can get a countersink tool pretty cheap at Harbor Freight.  This guys videos have some good discussion on how to avoid these types of problems:

Start watching this one at minute 3:27:

http://www.youtube.com/user/smbstressfest#p/u/15/PG2MsXz0CQw

and then this one around minute 6:20 and watch the rest of the video:

http://www.youtube.com/user/smbstressfest#p/u/13/G935HoZhCmo

 

[fourdogslong]

Thanks guys for the help. Almost all of the drilling is done, I'll just have to install a pickguard as soon as I find someone who can make a custom one for my LP. The results are ok and with the hardware on it's perfect.