Tuesday, November 21, 2006

Calder violin case - bow holder design process

Design engineer Barry Noble and I have been working on the bow holder for the Calder violin case.

As always we want a design that works well, is simple to use and can be hand made using materials that sit well with the leather and velvet we use. Top end bows cost upwards from $3000 and so the holder is an important component.

And as always creating what seems a simple unit turned out to be another major design process.

Barry's first idea was a simple modification of the traditional Hill type bow holder. To get away from the two piece construction of the Hill design Barry proposed turning a solid wooden piece which would rotate around a pin inserted into the base. Here's a blu tac model he made to show me what he had in mind - the Hill type holder is in the background.


We discussed this idea with local wood turner Nick Agar - he was concerned that wood turned and then planed along two faces would be too weak.

Next I came up with an idea very similar to the Hill but which I thought could be made by milling a section of synthetic wood and then cutting the section into slices. Here's the sketch.

Bow holder sketch 3:4.jpg

Barry felt we could do better than this. While working on another modification of the Hill holder his teenage son told him he was not being very creative...This challenge prompted Barry to come up with something completely different. With a bit of wire, some masking tape and a couple of rare earth magnets he created this.

Bow holder 1 with text.jpg

I recalled being told about a patented magnetic cello bow holder designed by Joachin Fiedler in Germany. This looks a beautiful piece of engineering but wanted our solution to be simpler.

Barry made up a wooden version of his magnetic holder for me to play around with.


To get some expert input I contacted Stephen Bristow a world renowned bow maker who is based in our part of the UK.

[All the way through this project I've been delighted by the help I've had from luthiers and people in this field - there is something about making musical instruments that seems to attract generous hearted folk.]

Stephen told us that musicians would be looking for total simplicity of use and minimum risk of the holder rubbing on or scratching the bow. He suggested that our design might not hold the frog securely enough to prevent rubbing damage.

Following this conversation with Stephen I came up with another idea.

Bow holder 2 sketch .jpg

Barry has taken a different approach and here is what he showed me today.

Bow holder 3

Now I'll spend some time mulling over our various designs as well as the possible option of making the holder in moulded leather.


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Looking for your feedback/comments

I see from my web traffic software there are plenty of people coming to read my blog. This is encouraging and I am grateful for your interest.

But most of you come and go silently - and I am interested to know what your think - about the blog itself and/or about our designs.

So if you have any reaction to the blog or the cases I would much like to hear about them.

Thank you.


Thursday, November 09, 2006

Bulletin board threads, crumple zones and suspension system

[I've had to remove some live links from this post as they have resulted in so much spam]

There have been some trenchant comments about the Calder case and some interesting suggestions on this Acoustic Guitar Magazine bulletin board www.acousticguitar.com/ubbcgi/ultimatebb.cgi?ubb=get_topic;f=7;t=007019;p=2 . Invigorating for me to read positive and negative feedback as well as some good questions.

Out of this discussion I've done some more work on the suspensions system needing a 'crumple zone' to protect instruments from the shock of a severe impact. I had planned to use a high density closed cell foam but now I'm researching potential alternatives.

The trick is to find a materials that is soft enough to cushions the instrument from shock and at the same time firm enough to stop the instrument being damaged from making contact with the side of the case.

Expanded Polypropylene EPP seems a good candidate - a very tough shock absorbing material used in crash helmets, car fenders and other high impact applications. I've been had good support from JSP one of the leading manufacturers of EPP - I'll be running tests on their product ARPRO.

Canadian company Godin manufacture an EPP guitar case for their acoustic guitars called TRIC.

Another interesting contender for the suspension system is a new UK developed materials called d3o which is causing a stir in the sports world.

And for those of you who are interested in more bulletin board stuff on suspensions systems here's a thread on Maestronet I contributed to recently - www.maestronet.com/forums/messageview.cfm?catid=4&threadid=314500&STARTPAGE=1&FTVAR_FORUMVIEWTMP=Linear" .


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Wednesday, November 01, 2006

Calder laptop case development

Laptops have become an essential tool for many musicians so we decided to include a laptop case in our range.

The construction is the same as our other cases - leather over carbon fibre - the interior is lined with calfskin.

The case will have a suspension system to provide the laptop with maximum protection.

Here are some CAD images of the design and shots of a pre-production model in Johan Ulvede's workshop.

Laptop CAD profile.jpg

Laptop CAD 3:4.jpg

Laptop shell 3/4.JPG



category: laptop case

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