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Floppy disk
9th March 2012, 12:14
Folks,

I have “inherited” 2 nice genuine handlebar counterweights for my bike’s handrail. :headbang: The problem is one of them is missing a cap, and I don’t seem to be able to find someone who can sell the cap. :brick:

I went to check if I could find a similar screw with the same threading and size so that I would try to do something with it, but Mitro10 and Bunnings seem not to have them. :argh:

I was wondering if I can get the cap made, and I would not mind to also replace the original cap I still have if the ones made are not 100 similar to it.

I live around Penrose but I have no idea what name and type of business that would do this and I don’t have the tools for such DYI stuff. So your help will be appreciated a lot. :scooter:

I have uploaded photos to the following so you can see what I am talking about:

http://homepages.ihug.co.nz/~radjrad/ncw.htm

Cheers.

Armi
9th March 2012, 13:40
I was wondering if I can get the cap made, and I would not mind to also replace the original cap I still have if the ones made are not 100 similar to it.

I live around Penrose but I have no idea what name and type of business that would do this and I don’t have the tools for such DYI stuff. So your help will be appreciated a lot. :scooter:

Cheers.

I bet it would be pretty pricey to get one made. My dad's a toolmaker who could do it. Is it plastic?

Floppy disk
9th March 2012, 14:00
I bet it would be pretty pricey to get one made. My dad's a toolmaker who could do it. Is it plastic?

Cheers for the reply. It is solid plastic, but I guess I wouldn't care if the new ones are made of plastic or metal, as long as they fit. :rolleyes:

sleemanj
9th March 2012, 15:31
Cheers for the reply. It is solid plastic, but I guess I wouldn't care if the new ones are made of plastic or metal, as long as they fit. :rolleyes:

Maybe you could cast one with a silicone mould made from the existing one, and a two part resin pourd in the mould. Craft shops and the such sell this stuff.

Or, do it cheap with plaster of paris to make the mould from the original, and then press kneadit into said mould (or mix up a bunch of araldite/similar and pour it in). Even if you just did the dome on top you could simply set a long bolt into it from the underside to go through the weight and bolt to the bar directly.

Old Steve
9th March 2012, 19:22
Plastic threads are a bastard. I work in an engineers supply shop, and we see all sorts of plastic threads, non of which we can match in any standard metal thread. You could get one (or two) machined up by a competent machinist but I wouldn't like to pay the price.

You could fill the hole in the bar with a two pot mix, something like the Loctite Aluminium/steel filler, and machine a standard metric thread into it with a drill and the appropriate tap. Then you just need the counterweights and the right metric bolt (probably a button head set screw in stainless steel would be best) to match the thread you've tapped.

Ocean1
9th March 2012, 19:38
Plastic threads are a bastard. I work in an engineers supply shop, and we see all sorts of plastic threads, non of which we can match in any standard metal thread. You could get one (or two) machined up by a competent machinist but I wouldn't like to pay the price.

It'll be a nominal dia and pitch, just probably not a standard, material is probably nylon or acetyl, as you say, no problem for a competent machinist. Take half an hour, maybe 45 min if you had to make a jig to hold the thread to cut the dome. Add $20 for tha plastic and call it $60.

Trick is finding a competent machinist with half an hour to spare, willing to do a half hour job...

Floppy disk
9th March 2012, 22:43
Maybe you could cast one with a silicone mould made from the existing one, and a two part resin pourd in the mould. Craft shops and the such sell this stuff.

Or, do it cheap with plaster of paris to make the mould from the original, and then press kneadit into said mould (or mix up a bunch of araldite/similar and pour it in). Even if you just did the dome on top you could simply set a long bolt into it from the underside to go through the weight and bolt to the bar directly.

I like your suggestions bro. That kneadit seems to be interesting. The challenge is to get the mould properly done (I have never done it before except when I was a kid) and to fill it up fully with the kneadit otherwise the output could be funnily shaped.

The long bolt might be interesting too, getting it inside a kneadit-made dome might just work.

It looks like I have some experimentation to do over next weekend.

Thanks all for the suggestions.. :rockon:

madkiwi
11th March 2012, 18:45
Any of my machinists could do this without a problem.
Problem for you is we have a $70.00 minimum charge. If you are interested PM me. We are in Rosebank Rd

hayd3n
11th March 2012, 19:58
it isint difficult to turn a thread on a lathe just find some bugger who will
its most likely nylon but maybe hdpe