Press Fit Help Please ???

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umahunter

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I'm making a blade tension handle for my 4x6 bandsaw the shaft is steel but the knob will be aluminum is there a rule of thumb for how may thousands under the the knob should be to press fit the knob onto the shaft with a 20 ton shop press thanks for any help20160318_185531.jpg
 
I don't think press fit will be good enough for that. My first choice would be a key if you have the means. If not I would pin it with a split pin.. A press fit will work lose with the tension od the handle.
 
I recommend that you positively key them together for a band saw tension knob, especially since you are using dissimilar metals. Otherwise it might slip on you. A cross pin would work, and threading them together plus Loctite would work as well.

Edit: You beat me to it, kdgij. Great minds think alike... :-|
 
I was gonna press it with some locktite the drill and tap a set screw does that sound good
 
umahunter said:
I was gonna press it with some locktite the drill and tap a set screw does that sound good
Click to expand...

I think if you press it with some Locktite bearing lock, it will probably not come apart. That stuff works.
 
So if I was gonna press fit it how many thousands over would be good for the shaft like 1 to 2
 
My simple rule of thumb for interference fits is .0005 + .0005 per inch of diameter (in mm about .01 mm + .0005 per mm of diameter) but Machinery's Handbook gives a lot more detail. {And yes the .0005 stays the same in each formula.}

I think the commentators who worried about an interference fit, especially between different metals are correct. A simple way to avoid problems would be to use a "scotch key". Just drill and tap a hole parallel to the axis of the handle, but position the hole so that it is half in each piece. The screw that goes in the hole will serve as a key. Here is a thread that mentions a "scotch key":
http://bbs.homeshopmachinist.net/threads/29437-Round-keyway-question
 
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