Double Bass shaping a new bridge

[swamprocker]

OK....so I have the new bridge, delivered yesterday \m/

i don't imagine much issue shaping the top...but now concerned about the feet.

the new bridge is much thicker. the only part i can get to match up is the heart in the middle. But even if i go off that, then the feet would be too thick...

should i use the feet as my focal point, to keep them thin when all is said and done?

 

[iiipopes]

Hi.

Yep, as the "rough" mating, before and after using the spreader.

But, after that it's very easy and quick job to carve the feet to match the top exactly. That takes only a few minutes IMLE, so why on earth would anybody skip that important part of the mating?

Regards
Sam

Thanks.

 

[360guy]

OK....so I have the new bridge, delivered yesterday \m/

i don't imagine much issue shaping the top...but now concerned about the feet.

the new bridge is much thicker. the only part i can get to match up is the heart in the middle. But even if i go off that, then the feet would be too thick...

should i use the feet as my focal point, to keep them thin when all is said and done?

Well shaping a bridge is not as easy as you might think. I would suggest reading Chuck T's instructions from his book. I've done a number of bridges ( never used a spreader, except with cellos) and I can tell you it's an involved process.

 

[swamprocker]

by no means to i expect it to be anything less than time consuming.
i've got Gollihur's instructions to help guide me.
but looking for some hands on experience tips.

 

[gbaker]

Here is a good link.

http://www.musictrader.com/fittingabridge.pdf

Note you may have to reduce the top of the toes as well as the bottom fitting to get the proper toe thickness. Do this last.

With adjusters don't worry about the spreader. Rough trim the bridge top and bottom then fit the adjusters. You will likely have to fit the feet to the top again, I always do and I drill the bridge in a press and vice before cutting it.

 

[bssist]

The compression stress on the top of the bridge results in the feet spreading apart a little bit (~ 3mm?). If you fit the feet without taking that into consideration, the feet will not feet once the strings are under tension. So we use a tool called a bridge leg spreader that pre-stresses the bridge to approximate the position they will take under load. Then we fit the feet.

You can either buy them or make them. I made mine out of a small turnbuckle, so that I could simply twist the middle, and both ends would move in or out.

Does that help?

Ah, yes. That clears it up. Thank you!

 

[T-Bird]

Hi.

Well shaping a bridge is not as easy as you might think. I've done a number of bridges and I can tell you it's an involved process.

Involved, yes, but difficult, well that's a matter of opinion I'd say.

It was a while ago, but I'd say it took me about 2 hours to do the 1/2 bridge and slightly more for the 3/4.

Here is a good link.

http://www.musictrader.com/fittingabridge.pdf

A good link indeed, looks a lot like the one I came across back in the day when doing my first .

With adjusters don't worry about the spreader.

I haven't used or installed adjusters, yet, but care to elaborate a bit?

The ones I'm about to turn one of these days will probably be rigid enough not to bend, if that's what You mean.

I was planning to first fit the bridge, then drill the holes, cut the feet, install the adjusters and mate the feet to the top again (with the spreader) if necessary.

I'm also planning to most probably use LH/RH threads in order to reduce flex. Any thoughts about that?

Regards
Sam

 

[swamprocker]

well...got it shaped. Difficult, not really. Tedious, YES.
Just hope I got the shape right. haha.
took probably 5 hrs of sanding by hand.

hopefully it fits. i have to set the soundpost and put the new gut strings on, then position and cut the string slots.

 

[ethnotime]

How is the bridge fitting? I might have to take the sandpaper route as well.

 

[T-Bird]

Hi.

^Yeah, we're dying out here to hear how it went?

Congrats for at least trying it in any case though, despite of all the nay-sayers.

Regards
Sam