Material Choice

[VicParticipant @vic]

And Design. I’d like to make a knife sharpening jig but I’m not sure of the best way of making the clamps. There are two main designs I’ve seen.

The first is one piece of machined aluminium alloy. Easily made but does it need some type of special alloy or heat treatment to stop it taking a permanent bend?

The other is fabricated from several parts using spring steel. Quite a fussy design but I’ve seen it used on quite a few jigs, even commercial ones. My concern here is getting some suitable stainless shim stock that’s springy enough but that can still be drilled easily enough. Note the use of stainless steel rules in the home built version below!

Any thoughts?

[halfnutParticipant @halfnut]

For home use I would go with the aluminium. No heat treatment needed if you use one of the high strength grades. The old favourite is 6061 T6, the original Duralumin developed for aircraft.  And 7075 has become popular in recent years for model engine parts such as conrods etc.

The large bore hole in the design pictured will allow it to flex without taking a permanent set.

[JasonBModerator @jasonb]

Dural was closest to 2014 and the old HE15, 6061 or if in the UK the more readily available 6082 was close to HE30.

My Tormek Grinder’s knife jig is just zinc alloy castings. I can’t see that anything more than 6082-T6 would be needed and it is easy to machine and cheaper than Dural.

[halfnut]

On halfnut Said:

For home use I would go with the aluminium. No heat treatment needed if you use one of the high strength grades. The old favourite is 6061 T6, the original Duralumin developed for aircraft.  And 7075 has become popular in recent years for model engine parts such as conrods etc.

The large bore hole in the design pictured will allow it to flex without taking a permanent set.

Thanks for that. I’ll have a look to see what’s available. 😉

[halfnutParticipant @halfnut]

Good run-through on ally grades here. https://www.redbackaviation.com/aluminum-the-most-common-grades/

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