First project-sheave

JohnCT

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Feb 2, 2018
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Thanks to Dave, I have metal to make a replacement sheave for my Snipe sailboat.

Dimensions are 31mm dia, 7.8mm wide, 6.3mm hole and I don't have any way to measure the radius for the groove, it is rounded for wire rope.

The original is bronze and probably original from 1985, there was enough corrosion around the sheave to prevent from turning, and a deep grove got cut on one side.
Pictures to follow
 
Hi John , last time I dealt with a wire sheave it had a "V" type groove with the radius for the wire rope at the bottom . I would just measure the wire rope and then make the groove a little wider so that there is no binding . Also if you are not aware of this place , I find it very useful for making blocks and stuff . http://www.duckworksbbs.com/category-s/328.htm
 
Thanks for the info, I tried doing a little on it last night and I'm not happy with the results, I'll try to post pictures later, that's not working very either right now
 
What material are you using? What is the diameter of the wire rope?
 
aluminum, and it's closer to wire then rope, 1/8" maybe, didn't measure it.

I'm getting a lot of chatter marks and the finish sucks compared to last aluminum parts I turned
 
Ok. How are you holding the work piece?

Sent from my SM-G530T using Tapatalk
 
There is a lot of contact area in the sheave profile. Your chatter may be due to the amount of contact area with the tool.

I would use a parting tool to make the groove in the middle, then a left and right hand tool to create the angle on the sides.
 
Thanks, I'll see what I can come up with. My overall finish is really poor, even on the facing and sizing cuts.

I'm also running a lot slower then I did when I made the spinnaker pole parts, I'm thinking that might have something to do with it also.

It's a new skill, will take some time to learn
 
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