Spreading the feet to fit a bridge. Is it necessary?

[brevardbass]

When you're fitting a new bridge, do you spread the feet 3-4mm before you use the lipstick method to determine if the feet are making full contact with the top?
I wanted to buy one of Bob Gollihurs' 60 dollar bridges and attempt this myself....after perusing the forums, I had noticed only one poster provided a link to Lars Kirmsers' site, and I wasn't sure if Arnold, Jeff, Ken and Bob deemed this as necessary or not.
I had a bad experience with a local luthier and was going to attempt this myself. For 60 bucks I thought I'd take a whack at it and if I screw something up, the original bridge will be intact if I need to take it to another shop.
Thanks in advance to everybody who's posted on this subject before....the pool of knowledge here is incredible.

[Dr Rod]

my question is: if you do spread, how do you know how much?

bridges have different woods, heights, thicknesses, and the string angle is different from bass to bass which alters tension, not to mention the type of string etc...

[Don Harris]

I've only done it once, but I started fitting the feet with a 2mm spread and after getting close, I measured with string pressure and without. Turned out to be a 1.5mm difference, so I finished fitting with that spread.

[Bob Branstetter]

Originally Posted by brevardbass

..after perusing the forums, I had noticed only one poster provided a link to Lars Kirmsers' site, and I wasn't sure if Arnold, Jeff, Ken and Bob deemed this as necessary or not.

I find a leg spreader useful when fitting Belgium style cello bridges, but I don't use one or find it desirable when fitting bass bridges.

Sent from my iPod Touch

[brevardbass]

Thanks Bob and Don.

[MingusAmongUs]

I used to make a drink called The Leg Spreader

..I'm here all week

[Matthew Tucker]

I was wondering how long that would take ...

[MingusAmongUs]

Originally Posted by Matthew Tucker

I was wondering how long that would take ...

I knew I'd regret it but I couldn't resist. Apologies all around.

[Heifetzbass]

Originally Posted by MingusAmongUs

I used to make a drink called The Leg Spreader

..I'm here all week

Used to?

[Silversorcerer]

Originally Posted by MingusAmongUs

I used to make a drink called The Leg Spreader

..I'm here all week

Apologies accepted;- So what's the recipe?

[MingusAmongUs]

Originally Posted by Heifetzbass

Used to?

Married now, kid on the way. I guess it worked.

@Silversorcerer - it was just a (bad) joke. But I seem to remember a line from a bad skiing movie called Hot Dog, where the recipe is divulged. Something about a scoche of Myers' Rum....

[Wal Pawlik]

Um.. what is a legspreader and why?

[1st Bass]

It is essentially a tiny screwjack used to push the legs of a bridge outward to approximately the position they will occupy when subjected to the downward force of the strings under full tension. The theory is that you want the bridge to fit correctly under full compressive stress, not just when it is relaxed.

You can make one out of a tiny turnbuckle if you want one-- or you can buy one for < $10 USD from International Violin Co. (catalog page 69, #T-92, Cello bridge foot spreader)

[Damon Rondeau]

I've fit maybe half a dozen bridges. Never used a spreader and haven't noticed any trouble for not having used one. Here's a question though: if the string tension is enough to spread the legs of that bass bridge 1.5 mm, isn't the tension also enough to influence the shape of the top you're fitting to? In other words, if you're going to fuss with the spreader, do you not have to fuss with other variables? Or is it just not relevant?

[Krispy]

Originally Posted by Damon Rondeau

I've fit maybe half a dozen bridges. Never used a spreader and haven't noticed any trouble for not having used one. Here's a question though: if the string tension is enough to spread the legs of that bass bridge 1.5 mm, isn't the tension also enough to influence the shape of the top you're fitting to? In other words, if you're going to fuss with the spreader, do you not have to fuss with other variables? Or is it just not relevant?

Isn't that in fact what happened to this Kay (n00b question)?

[Dr Rod]

Originally Posted by Damon Rondeau

I've fit maybe half a dozen bridges. Never used a spreader and haven't noticed any trouble for not having used one. Here's a question though: if the string tension is enough to spread the legs of that bass bridge 1.5 mm, isn't the tension also enough to influence the shape of the top you're fitting to? In other words, if you're going to fuss with the spreader, do you not have to fuss with other variables? Or is it just not relevant?

thank you

[Silversorcerer]

Originally Posted by Wal Pawlik

Um.. what is a legspreader and why?

I googled to find one and this is what I found (for real). Just use a turnbuckle.

[Keyser Soze]

Originally Posted by Silversorcerer

I googled to find one and this is what I found (for real).

Man, way to kill the thread. Nice to see customer satisfaction tho, in whatever arena.

The right tool for the job....

[forester]

confirmed addict....hurts sooo good...