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Building something like a bass viol #12: The Bridge

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Blog entry by Dave Rutan posted 12-02-2020 01:07 AM 581 reads 0 times favorited 6 comments Add to Favorites Watch
« Part 11: Doing some finishing Part 12 of Building something like a bass viol series no next part

I may have mentioned that I had to make every bit of this instrument save the strings. Supposedly a bridge for this is available, but I wanted to do it myself.

I found an eBay seller who graciously put the measurements in the photo for the auction, so I took the picture, sized it properly and printed it out for use as a template.

Then I used my scroll saw to roughly cut out a pair of blanks. N.B. I messed up these first two in the final fitting and ended up making a third one. The first two were from some kind of maple. The third was from white oak. Purism aside, it will work for this purpose.

After giving the bridge blank a going over with rasps and files, I fit the feet to the top of the instrument with sandpaper and a bridge-fitting jig.

Then I put the correct curvature on the top and make sure the height holds the strings at the appropriate height. When that’s done I locate and file the 7 grooves, making sure they are equally spaced.

Lastly I rubbed on some boiled linseed oil to let the grain pop. I’m not sure if this is typically done, but I did hear one violin guy on YouTube say that he does it, so I guess it does no harm.

-- Ni faru ion el ligno!



6 comments so far

View Dave Polaschek's profile

Dave Polaschek

8272 posts in 1791 days


#1 posted 12-02-2020 02:46 AM

The bridge is just held on by the tension of the strings, right?

I think finish on the bridge won’t hurt anything. It’s transmitting the sound via vibration, so as long as you don’t finish inside the grooves or on the bottom of the feet, I think everything will be ok. Or that’s what my memory of my acoustics physics class almost 40 years ago tells me.

-- Dave - Santa Fe

View Craftsman on the lake's profile

Craftsman on the lake

3873 posts in 4647 days


#2 posted 12-02-2020 02:54 AM

I’m so curious to hear what this sounds like. If it will have depth without the large soundbox or sound like a more ethnic instrument. I hope you are able to post some video with some decent sound quality so we can get a good idea of what it does. You’re almost there!

-- The smell of wood, coffee in the cup, the wife let's me do my thing, the lake is peaceful.

View Dave Rutan's profile

Dave Rutan

2009 posts in 3398 days


#3 posted 12-02-2020 11:26 AM



The bridge is just held on by the tension of the strings, right?

I think finish on the bridge won’t hurt anything. It’s transmitting the sound via vibration, so as long as you don’t finish inside the grooves or on the bottom of the feet, I think everything will be ok. Or that’s what my memory of my acoustics physics class almost 40 years ago tells me.

- Dave Polaschek

Yes, the string tension holds the bridge on. No glue.

-- Ni faru ion el ligno!

View Oldtool's profile

Oldtool

3309 posts in 3400 days


#4 posted 12-02-2020 12:42 PM

Nice work, good idea regarding using the Ebay photo as a pattern. I’m guessing the bridge design isn’t critical to the function other than the height and string spacing, and maybe the top arc. If that is the case, maybe the decorative portion could include the maker’s initials?

-- "I am a firm believer in the people. If given the truth, they can be depended upon to meet any national crisis. The point is to bring them the real facts." - Abraham Lincoln

View Dave Rutan's profile

Dave Rutan

2009 posts in 3398 days


#5 posted 12-02-2020 01:48 PM



Nice work, good idea regarding using the Ebay photo as a pattern. I m guessing the bridge design isn t critical to the function other than the height and string spacing, and maybe the top arc. If that is the case, maybe the decorative portion could include the maker s initials?

- Oldtool

I’ve never seen that. Usually they mark the bridge with a branding iron with their name on it. I just ‘sign’ mine under the arch with my initial and the date. This one I marked as ‘R1220’ It lets me know that it’s one of ‘mine’ and when I made it.

-- Ni faru ion el ligno!

View robscastle's profile

robscastle

8215 posts in 3413 days


#6 posted 02-16-2021 10:25 PM

OMG Dave

You made your poor scroll saw wade through huge chunk of material several times, must have had one hellish sharp blade.

You are a very naughty boy ! ( tee hee)

Excellent results BTW

Keep up the good work.

-- Regards Rob

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