Monday, January 30, 2012

Hofner Colorama II restoration project (part 16) - making a new bridge

In the last blog post, we made a new nut for our vintage Hofner Colorama II. Also needing doing is an improved bridge.

The original one should've looked like this:



However, here's the (replacement) one I got on THIS guitar:



Apart from looking wrong (not necessarily a big problem), it has the wrong radius, wrong string spacing, and is not compensated in any way for proper string intonation.

The base is almost correct, dimension- and look-wise, so I'm going to keep it and make a new top.

First I get a brass bar:



Cut it to length to match the base:



Mark the position of the holes and hit them with a punch:



Now the tricky part for me, since I don't have a drill press - drilling the holes perfectly straight:



Holes done:



Now turned over to check how close I got. Not bad.



Quick check with the base before taking this any further:



Sides are now marked with a 9.5 radius gauge to match the neck:



The brass is now filed to shape, checking constantly with the radius gauge to make sure nothing is going horribly wrong.



And here's the bridge after that:



The guitar is then quickly strung up (I've been doing a few things in parallel here, so the guitar finish is done now - I'll do a post about that part soon), in order to determine how to shape the top of the bridge to intonate the strings correctly.

First, I put some little pieces of copper under each string. These are actually little cutoffs of thick copper wiring:



Then I check with a tuner and move the copper wires forwards or backwards until the strings are intonating properly, then mark the position with a pen.



After that, I remove the bridge from the guitar and mark it with a couple of lines that will more or less cut through the six marked positions. There's a certain amount of compromising going on here, but it should still end up giving acceptable results.



After that, I start to shape the bridge using fairly fine files:




Giving us this basic shape:



Then I start finishing it, starting with 400 grit sandpaper and going up to 2000 grit:



Finally I hit it with rubbing compound:



For the sides and back, I put the sandpaper on a flat surface and move the bridge itself. Other than that, it's the same finishing process, from 400 grit to rubbing compound.



And here's how it looks after that:




Finally some slots are added to keep the strings in place:


The aim was to follow a similar style to the bridge that would've come with the guitar originally, while correctly compensating it for an unwound G string (the original would've been shaped for a wound G string). I think it came out OK.

9 comments:

Julian said...

Incredible!

Anonymous said...

Hi there,
very impressing - the whole project. But here are some questions. Before you strung up to determine correct intonation - how did you find out the correct position for the bridge in oder to have the exact scale length? I've thought the bridge is installed with an slight angle. And the bridge isn't fixed to the body, right? Isn't that a huslte when you put it together?
Actually I'm looking for a bridge for a Hoefner Bass 185 Galaxy that is a very similar brass piece. Maybe I'going to start a filing project too, let's see.

Woody Hill

stu said...

Hi Woody,

Very good questions. Firstly I made an educated guess with the initial bridge position, based on where I knew the original one sat (without knowing this information, I would've measured the distance from the nut to the 12th fret, multiplied this by two, and added a couple of millimetres for good measure). Had it been too far forward (or back), it would've become apparent pretty quickly if I couldn't get it to intonate properly. As it turned out, it was perfect. I couldn't believe my luck.

I didn't need to angle the bridge since it was thick enough that I could slant the ridge along the top sufficiently. If I hadn't been able to do that (say if I still needed to move back even further for the low E string), then I would've slanted the bridge itself. As it happens, it wasn't necessary.

I did end up fixing it to the body once I was absolutely sure it was in the correct position. Luckily the base I used had two perfect screw holes for that (the originals didn't). I wouldn't really have been that bothered, but when you're using that bridge with a tremolo, you really need to secure it.

I hope that answers your questions. Let me know if I missed anything, and good luck with your bass bridge.

Anonymous said...

Hi stu,
thank you for the answer. Today I bought a steel bar that I accidentally found in a thrift shop. It seems kind of suitable for the bridge but I haven't decided yet if I better should use brass.
Maybe aluminum is an (not so vintage) option too. I've heard that Danelectro made their nuts out of this for their special sound. And I like that kind of sound (didn't you play Link Wray on your demo?) But this bridge would be for an bass model, well. Anyway I have to wait until I visit my parents where I could do it in my fathers old and very nice workshop. And thanks for all the time it takes to publish this information about your project. I think one shouldn' t disregard that.

Woody Hill

Zak Zerby said...

I thought this was a good series of posts. Then I saw that you made your own bridge... Now it's an AMAZING series of posts. Thanks for having this blog, it has been so helpful. I'm going to be assembling my own Telecaster, much like you did, and this site has absolutely been the best source I've found so far.

Since you seem like a veritable guitar guru, I'll ask you one of my questions. Do you know the best way to lacquer a fretboard? And could a rosewood (instead of the standard maple) fretboard be lacquered? I know they are usually unfinished, but I have seen Rickenbackers with them lacquered. I just love the feel of those finished maple Strat fretboards. Again, thanks for all the info and advice you give away here.

Now if you could just do a post about scalloping frets.

Thanks,

Zak

stu said...

Hi Zak,

There is no NEED to lacquer a rosewood fretboard, BUT don't let anyone tell you you can't do it if it's something you like. Certainly rosewood can be lacquered (just look at the sides and backs of many acoustic guitars). It's simply a case of prepping the surface well and spraying on the lacquer (right over the frets), then scraping the lacquer off the frets once it is dry. So, basically, just like lacquering a maple board. Another option you might want to think about it applying some sort of oil instead of hard lacquer, but I get the feeling that's not what you want to do.

Zak Zerby said...

Thanks for the advice. I really appreciate your help.

Anonymous said...

Hi Stu,
I finally finished the brass bridge for the Hoefner Bass Model 185. Inspired by your superb example I started this project. I could borrow an original bridge from a friend which I could use as a template. And a locksmith helped me out and cut the two brass piece into the correct dimensions. Then I had to do the filing. I think it turned out very good. The locksmith convinced me that we should nickel-plate it – so the result will be very close to the template. (How can I insert a pic?)

The next problem are the pickups. They have a very low output and I could not measure any resistance. Although they do not humm when plugged in and don't sound bad. But I don't understand that they produce (a relatively low) sound (so they are not completely dead) and they fail the continuity test at the same time. Well, you showed us how to rewind a pickup. Maybe that'll be further inspiration to continue with this matter.
Thank you again.
Woody Hill

stu said...

Hi Woody,

Sorry, for some reason I didn't spot your comment until now. Congrats on getting the bridge done. I'd love to see photos of it. You can upload a picture to any number of image hosting sites. I used to use Imageshack, but it's become a real pain to use now, so I advise against it. Picasaweb works well (I use it to host the images on this blog) and I believe Photobucket works well too. Then all you need to do is post a link to the image in the comments here and we can click to see it.

Good luck with the pickups. (Are you sure it's not a problem with the other electronics? Did you try measuring the resistance of the pickups completely disconnected from anything else?)

Stu