Sign in to follow this  
Jonathan M.

Making Violin Bending Iron

Recommended Posts

I am in the need for a violin rib bending iron so I decided I am going to machine my own out of aluminum. It seems like there is a lot of variation in the shape when looking from the top down at a iron. I was wondering if there was a shape for the iron that has been known to work for most people. I am looking to make early 1700 Strad ribs for now. Once I get a good shape and I start the project I can post pictures of the process if anyone would like.

Share this post


Link to post
Share on other sites

Looks like the shape of an elongated egg, with one end larger than the other. this is usually good enough for various C bouts models. A look at some violin posters with real time measurements will give you a pretty good idea.

But many makers seem to do very well with just rod-likes irons.

Share this post


Link to post
Share on other sites
Guest

I am in the need for a violin rib bending iron so I decided I am going to machine my own out of aluminum. It seems like there is a lot of variation in the shape when looking from the top down at a iron. I was wondering if there was a shape for the iron that has been known to work for most people. I am looking to make early 1700 Strad ribs for now. Once I get a good shape and I start the project I can post pictures of the process if anyone would like.

Hey Jonathan

I asked this question myself in that thread and did'nt get the precise answer I was looking for...If your a machinest and are going to machine the billet yourself...then I can apreciate your question...the iron I used was pre-shaped...but to this day it still needs finishing...the ribs don't come in complete contact with the iron...I mean there are high spots...and since I like highly figured ribstock, I've learned through advice here and many cracked ribs that it is very important for the wood to be touching the iron completley while pulling hard on the strap...take that into consideration while finishing the sides of the shape...which if you're using a Bridgeport then there is no problem...if you're finishing on a belt sander, check the flatness...I think that might be a point that is often overlooked...at least it was on the iron I bought off Ebay...

For the best shape I would perhaps trace a Strad cbout and make it a little tighter...because after cooling the rib will flex back..

Good Luck and post some photos...if you can

-Ernie

Share this post


Link to post
Share on other sites

What Ernie said.

I would make it shorter across than the smallest rib you wish to ever bend, and tighter radii on each end. There is always a little bit of spring-back with the wood after bending, so you want to over-bend the rib a little to arrive at the right shape.

If your iron is exactly the shape and size of the finished rib shape, you'll never be able to put enough over-bend on the rib.

Share this post


Link to post
Share on other sites

What Ernie said.

I would make it shorter across than the smallest rib you wish to ever bend, and tighter radii on each end. There is always a little bit of spring-back with the wood after bending, so you want to over-bend the rib a little to arrive at the right shape.

If your iron is exactly the shape and size of the finished rib shape, you'll never be able to put enough over-bend on the rib.

what they all said, and.... I would warn against aluminum....ant bit of corrosion will leave a nasty black mark on the rib,That would be a pity.....I used stainless for mine.

Share this post


Link to post
Share on other sites

Here's my attempt at making an iron. I cast this in bronze many moons ago and, as you can see, never finished it. I cast one in aluminum at the same time which I use but I should really get this one going as I think it would be nicer to work with.

post-36570-0-18140400-1337260083_thumb.jpg

post-36570-0-57382800-1337260086_thumb.jpg

Share this post


Link to post
Share on other sites

I have an aluminum iron and have never had any black marks on my wood. I wonder if it is a matter of which alloy you use.

For my iron I used a shape intended to allow the making of a small Andrea Amati model in case I ever wanted to do one. The iron is about 81 mm wide.

Share this post


Link to post
Share on other sites

I have an aluminum iron and have never had any black marks on my wood. I wonder if it is a matter of which alloy you use.

For my iron I used a shape intended to allow the making of a small Andrea Amati model in case I ever wanted to do one. The iron is about 81 mm wide.

I wonder...I just tried two types,both fairly clean with little corrosion, and got black marks from lightly rubbing with wood...It could be that when you bend you don't rub much ..but more of a pressing action ...or like you said ,it could be the alloy ????? or the polish, who knows?

Share this post


Link to post
Share on other sites

I wonder...I just tried two types,both fairly clean with little corrosion, and got black marks from lightly rubbing with wood...It could be that when you bend you don't rub much ..but more of a pressing action ...or like you said ,it could be the alloy ????? or the polish, who knows?

"Before placing the rib on the heater, we put a wet paper towel on the heater to generate hot steam, which helps the rib to bend more easily." -

Share this post


Link to post
Share on other sites

This is only my opinion and is worth what it's costing, but I see no real use for any but the smallest curve you need. The flatter curve is unlikely to perfectly match much of your shape and the gentle curves are pretty easy anyway. Therefore, I use a cylindrical iron, presently one inch diameter. Mine is chrome plated so unwanted colors are not an issue. But I've only made about 65 fiddles, so I'm no expert.

Share this post


Link to post
Share on other sites

the larger curve might come handy if you want to give a shot at viola or even cello (assuming the iron is long enough for larger ribs).

Strangely with the chinese bending iron I am using it's the larger curve that is best for the violin I made. But the combination is perfect for 1/2 and 3/4 sizes violins.

Share this post


Link to post
Share on other sites

The larger curve is useful for pre-heating the rib, which you then slide into whatever position best suits your desired curve. Of course even with an ovoid iron it's often more of a dance that that, but nothing like the back and forth required when working with a cylinder.

Share this post


Link to post
Share on other sites

The larger curve is useful for pre-heating the rib, which you then slide into whatever position best suits your desired curve. Of course even with an ovoid iron it's often more of a dance that that, but nothing like the back and forth required when working with a cylinder.

That's valuable, because I never take a rib into the tight bend without pre-heating it on a gentler bend.

Backing strap pressure is also important. Ya can even bend highly flamed cello ribs dry if you're willing to lay your body back about 45 degrees on the backing strap.

To do this, you need to trust your strap, the attachment of the bending iron to a solid support, and all attachments within the bending iron.

Ain't like I've never pulled hard on a strap, had some part fail, and banged my head on the opposite wall. :lol:

Share this post


Link to post
Share on other sites

I have a bending iron my friend made for me years ago. It is essentially a 1” pipe with the end sealed. An electrical heating element of some sort was inserted into the pipe and wired to a rheostat to control the heat. I have used it for 30 years and it is still working. The man (Frank Henderson) who coached me through my first violin in 1980 had aluminum blocks the shape of the ribs. The blocks were heated by electrical wires. He would leave the wood on the blocks over night at a very low heat and the next day he would have perfectly formed ribs, very dry and without spring back. I have considered making the same type of jig but not knowing a whole lot about electricity I am concerned about just hooking up hot wires to an aluminum block. I wonder if the block would just get hot or if I touched it would I get a jolt of electricity. I must be missing some important detail in the hook up. Can anyone advise me? Thanks.

Share this post


Link to post
Share on other sites

I have a bending iron my friend made for me years ago. It is essentially a 1” pipe with the end sealed. An electrical heating element of some sort was inserted into the pipe and wired to a rheostat to control the heat. I have used it for 30 years and it is still working. The man (Frank Henderson) who coached me through my first violin in 1980 had aluminum blocks the shape of the ribs. The blocks were heated by electrical wires. He would leave the wood on the blocks over night at a very low heat and the next day he would have perfectly formed ribs, very dry and without spring back. I have considered making the same type of jig but not knowing a whole lot about electricity I am concerned about just hooking up hot wires to an aluminum block. I wonder if the block would just get hot or if I touched it would I get a jolt of electricity. I must be missing some important detail in the hook up. Can anyone advise me? Thanks.

I have seen videos where makers use a similar technique except that the metal form is simply placed on top of a hot surface first then the wood is bend around carefully and clamped for some time. And you can even do the same with the cold method, slowly bending the wood, little by little (Craig posted pictures several times). It works very well too but it takes longer than a bending iron.

Share this post


Link to post
Share on other sites

I bent my ribs on wood forms for 25 years; then I got curious and had to see what all the fuss was about regarding bending irons. I still like the wood form method, but I like the iron for bending purfling.

Share this post


Link to post
Share on other sites

Bronko,

Don't do it.

Mike

Probably good advice which I will heed. However, I would like to know how to hook up the electricity to the aluminum block. What is the key between the wires and the block?

Share this post


Link to post
Share on other sites

I have seen videos where makers use a similar technique except that the metal form is simply placed on top of a hot surface first then the wood is bend around carefully and clamped for some time. And you can even do the same with the cold method, slowly bending the wood, little by little (Craig posted pictures several times). It works very well too but it takes longer than a bending iron.

As a matter of fact I have bolted an aluminum block to an old electric frying pan. It worked out fairly well but took a long time to heat the block.

Share this post


Link to post
Share on other sites

Most electric heated bending irons use a cartridge heater, a small heating element that looks like a metal dowel with wires sticking out the end. These come in many different physical sizes, voltages, power ratings, etc.. I'm sure one could be found to heat whatever block of aluminum you might have.

Once you have the heater, simply bore an appropriate size hole in the aluminum, and slide the heater into the bore.

Look to ebay for a wide selection of cartridge heaters at very reasonable prices. A 250W , 120 volt heater would probably work for an average size iron.

Share this post


Link to post
Share on other sites

Most electric heated bending irons use a cartridge heater, a small heating element that looks like a metal dowel with wires sticking out the end. These come in many different physical sizes, voltages, power ratings, etc.. I'm sure one could be found to heat whatever block of aluminum you might have.

Once you have the heater, simply bore an appropriate size hole in the aluminum, and slide the heater into the bore.

Look to ebay for a wide selection of cartridge heaters at very reasonable prices. A 250W , 120 volt heater would probably work for an average size iron.

Thanks Bill. This is exactly the kind of information I was looking for.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
Sign in to follow this  

  • Recently Browsing   0 members

    No registered users viewing this page.