A DIY TONEARM - HELP PLEASE

[hallcon83]

Hi All , I am looking for a cheap S-shaped metal arm , sme and other S- shaped arm tubes alone go for 40.00 to 80.00 on ebay . . . so I am looking for a cheaper source, does anyone have any Ideas? - I was thinking along the lines of a " schick " style of arm. One thought I had was aluminum arrow shafts... has anyone any expierance with trying to bend one without it folding ? - Thanks for any help, dean

[kevinkr]

Originally Posted by hallcon83

Hi All , I am looking for a cheap S-shaped metal arm , sme and other S- shaped arm tubes alone go for 40.00 to 80.00 on ebay . . . so I am looking for a cheaper source, does anyone have any Ideas? - I was thinking along the lines of a " schick " style of arm. One thought I had was aluminum arrow shafts... has anyone any expierance with trying to bend one without it folding ? - Thanks for any help, dean

Have a look at Nanook's project tone arm here: my latest iteration of "Nanook's 219 tonearm"..

It's a very cool arm, and he has been distributing them for the cost of postage to those willing to experiment. I have one and am just about to get started with mine. They are very easy to replicate in the event that there are no more available, and the reports are very positive.

[nikongod]

Originally Posted by hallcon83

has anyone any expierance with trying to bend one without it folding ?

I have not tried this myself, but have been thinking of trying something similar.

Have you tried putting a steel cable the same size as the inside of the tube in it before you bend? Use lots of grease.

Let me know if it works.

[hallcon83]

Hi Guys - Thanks for the Ideas, - Hi Kevin I will get in touch w- Nanook and give the 219arm a whirl.... - Hi nikongod, - Thanks for the steel cable Idea - It had also occurred to me to try fitting something inside the tube to help keep it's shape, but your cable idea is better then what I had thought of - - I will let you know how it works, I'm not sure what size of tube I need . . . I guess I need to buy a headshell so I can match the arrow tubing to it. - I will try ebay, if you have a another source for a cheap headshell or just the connectors for headshells let me know - thanks, dean

[TerryO]

Originally Posted by hallcon83

Hi Guys - Thanks for the Ideas, - Hi Kevin I will get in touch w- Nanook and give the 219arm a whirl.... - Hi nikongod, - Thanks for the steel cable Idea - It had also occurred to me to try fitting something inside the tube to help keep it's shape, but your cable idea is better then what I had thought of - - I will let you know how it works, I'm not sure what size of tube I need . . . I guess I need to buy a headshell so I can match the arrow tubing to it. - I will try ebay, if you have a another source for a cheap headshell or just the connectors for headshells let me know - thanks, dean

Tightly packed sand, with sealed ends will help, however it may very well depend on the alloy used, as some of the harder one's might crack. Heat plus sand?

[Nanook]

arrow shafts are usually made of very high strength, brittle hardened aluminium. In fact that is one of the toughest things to do when making any arms out of this these.

I even had purchased some "soft" brass, and using a tubing bender crimped it, so I guess I need to get thinner walled brass, or heat the brass while trying to bend it, then heat treat it. Another thought is using aluminium tubing that is not heat treated, and then heat treating it after the shape and all possible machining or drilling is done.

Rather than an "S" shaped arm, a straight arm has many advantages. An offset headshell is easier to make or have made, than using soft aluminium and then heat treating it.

Another method could be utilized as well: use arrow shafts, but get some thin walled tubing (perhaps steel brake lines?) and bend the desired angle. Heat treating a small piece of steel tubing is much easier than a long aluminium tube. Cut the tubing long enough on one end to allow it to be inserted into the arrow shaft, the use silver solder or JB weld to attach it.

[SGregory]

I don't think this will work with an aluminum arrow shaft, but a good way to bend tubing is to fill it with water and freeze it. Will bend without kinking, but the shaft aluminum may tear.

[Nanook]

provides internal support! Great idea.

[AuroraB]

For bending electrical conduit one usually uses a tight wound steel spring inside.... ( for PC plastic conduit, that is.. )

[Straight Tracker]

You might try to attach plumbing fittings to the ends of the tubing. Then pressurize the tubing with a grease gun. Then bend it. Of course the tubing has to be cut a little longer than final size.
Years ago I built a bending machine to bend 7/16" diameter 6061 aluminum tubing into a full 12" diameter circle. I had no problems with doing that because I'd discovered a neat trick, apparently developed by a company called "Tools for bending". It involved a bending wheel with special geometry. If you are truly interrested in that method, I'll make a drawing for you and post it.

Ralf