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Securing a gear to a shaft

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Parksy

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Hi all

I was wondering what methods everyone uses to positively secure a gear to a shaft? Previously I'd just use a grub screw against a machined flat. A woodruff key would be nice but I won't go this option. Are there any other methods that I don't know about?

Thanks all for reading.

Andy
 

bazmak

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If the gear has a keyway,then its just as easy to machine a keyway in shaft as to machine a flat.If I can I then fit a grubscrew down on the key.Other than that I drill a large dimple in the shaft for a more positive lock with a grubscrew
Just made a mandrel for my thread in gearcutting
 

Brian Rupnow

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Best way, but quite involved, is the taper-lock hub and keyway way of doing things. This is the method used on larger industrial shafts, but not really necessary for model engines. I always cut a keyway through the gear (this requires a fairly expensive set of broaches and some form of arbor press) and machine a straight keyway in the shaft with an endmill. This is not for a woodruff key, simply a piece of square keystock. I make the hubs large enough in diameter to place one setscrew directly above the keyway, and one set screw 90 degrees from the key.
 

django

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You could just drill through the gear and shaft and secure it with a roll pin (seloc pin) or drill and ream it for a taper pin. Both are obtainable in very small diameters, I have some 1/16" taper pins.
 

bazmak

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Some gears can be a permanent fixture.When a gear/item needs to
be removed/replaced accurately on a regular basis then Brian Rupnows way
is the recognised engineering way. Types of key may differ but a sq key is the easiest.If you look at my mandrel in keycutting thread the key is overly long
for varies items to be fitted.The keyway in the gear does not necessarily
need a broach,for not too wide items I use an endmill in the mill the depth
of the keyway is not critical as the top of the key should have clearance
its the sides that do the locating and work
 

Hopper

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Instead of broaching keyways in gears etc i just do it in the lathe using a boring bar with a square-ended toolbit turned sideways. Move the carriage back and forth with the handwheel to get the stroke and use the cross slide feed to add depth of cut as you go. It does not take long at all to cut a keyway in model sizes. I've done up to a 5/32" keyway this way just recently for the main worm wheel on the GHT dividing head.
 

bazmak

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That's what I did Hopper before I bought the mill now I have moved on to using an endmill.Broaching is the proper way,but not everone has broaching equipment.I started trying to cut a keyway on my model shaper but its only a model
 

rodw

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I bought some second hand minuteman broaches a few years ago. The one keyway I have done was real easy so I am a fan of broaching keyways now.
 
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