UKC

http://www.cadre.org/bike_stuff/Campagnolo/Shifters/Syncro%202/IMG_1574.JPG

I'm looking for a cone shaped drill bit to drill a hole which matches the shape of the cone shaped/tapered piece of plastic in the image above, to drill a hole into a cylinder made either out of aluminium or plastic.

I'm starting to wonder if it's something too complex for the home fiddler, and might involve a stepped drill bit, which may require equipment I don't have to keep things in position accurately enough.

Has anybody any sources I could go to to find one, or solutions?

Thanks...

In reply to Timmd:

What is the OD of the White plastic piece?

In reply to Timmd:

Depending on the angle, a countersink bit might do the trick?

b

In reply to Timmd:


Appropriate shaped router bit in a pillar drill? or just make up some sort of jig to hold the piece and use the router directly.

In reply to Timmd:

Failing the above, it's a bit Heath Robinson, by will work, use an oversize drill bit to give you uour countersink. You could grind the leading edge of the drill to suit the angle required.

In reply to MarkJH:
Hmmn, I might go to a little local machine shop and get a quote, I'm kind of busy to be looking into router bits and making jigs.

Details will be provided shortly for what I'm wanting to do folks. (:~))

In reply to Timmd:

Careful use of a Dremel? You may find better shapes in grinding wheels than drills, which would work in aluminium/plastic - certainly for the depth you're after.

In reply to Mostin3:
I'd second the custom drill bit. You might find a tile drill isn't far off that angle, but a decent machine shop (particularly one with old chaps in it missing a finger or two) would probably grind a drill to suit by eye.

As a thought -is the angle particularly critical? it might be easier to lathe a bit of plastic to suit whatever angle you can easily make.

In reply to Timmd:
Prob just a standard drill bit (118deg), I get 123deg in inventor because its sat on its side so maybe twisted a bit. A small machine shop will soon be able to tell you.

In reply to Timmd:

Cone cutters.

http://uk.rs-online.com/web/c/tools/power-tool-accessories-drill-bits/cone-...

In reply to Timmd:

By looking at the nylon bit in the picture, a cone drill would be far too steep an angle

In reply to Timmd:

Those old Campag levers were rubbish. I doubt very much that if you replaced the cone shaped nylon washer with just a flat one and matching flat hole, it would make a much of difference to the poor functionality.

In reply to JLS:
I'm retro-modifying another gear lever, and want to place a cylinder inside the housing after bolting an offset flange onto the bottom and screwing a bolt into the side, and grinding the bolt head down to fit into a groove, the picture was pulled from google images to show the kind of hole I'm wanting to make.

Using a cone shaped grinding head, and then shaping a plastic cone shaped washer to fit the hole could be a doable solution...secure the washer onto the end of a drill somehow, and slowly rotate it while holding something abrasive against it until it matches the hole in the cylinder.

Ta for the thoughts folks...