Need basic machine shop question answered

[gsdelong]

I came up with the idea of making my own adjustable little dandy rotor.

I started this by drilling through the rotor with a 17/64th Drill and tapping with a 5/16 x 24th Tap and then screwed in a 5/16 x 24 Set Screw.

Her is the question although it works it is way to loose to hold adjustment.

Is this a problem with my technique or is there some trick or special type of set screw to buy that is much tighter in the threads.

Any help would be appreciated thanks in advance.

gsdelong

[Green Frog]

Bailey Boat has already done this... a stainless steel replacement rotor with an adjustment similar to what you mention that has a spring loaded arrangement that he advertises holds adjustment quite dependably. BTW, he has a patent on his particular process, but it is for sale for less (probably) than most of us could make one.

Froggie

[gsdelong]

He has a patent on making a set screw stay in place? Also This is for my own use not for resale, so I really do not think a patent is relevent.

I am not opposed to buying one from him and still may.

I like to learn things, so I am really looking for the original question to be answered unless you are telling me you can only make a set screw stay in place with a spring?

[country gent]

If the set screw is long enough a groove can be cut for a small o ring and that will create friction betwen threads and set screw yet still allow adjustment. A simple hand ground parting blade the appropriate width for the o ring will work. Cut the groove to depth of o ring -.005 - -.008 if o ring is .030 dia then .022-.025 deep groove at .030 width. Other wise turning a set scew with the thread fitted to the mating thread is an option also.

[Nobade]

Or you could put one at 90 deg. to the first so they would lock together. Like a Lyman sprue plate.

Or make an insert for the rotor with an O ring to hold it in place and shims under it to make it adjustable so you don't need a screw at all.

I have been known to fill those rotors with epoxy and drill them out to the right size.

-Nobade

[1hole]

A drop of medium hold Loc-Tite will prevent accidental movement and still allow you to change the screw.

[Silverboolit]

Could you drill a hole in the set screw and insert a piece of weed wacker line??It would act as a ny-lock nut.

[gsdelong]

Thanks for all the ideas, I have allways thought that this is what this site is about.

[bearcove]

Linseed oil is a good mild locktite

[257]

you can get set screws with brass or steel or delrin tips you can also get set screws that have a small hole in the side of the thread with a nylon insert that makes the fit quite tight. you can get spring plungers made out of steel,stainless,delron,nylon and the same for the acual balls to. 257

[Dave Bulla]

I'll second the double set screw fix.

I don't know how deep your hole is but if you put a long one in first and still have room for a short one, on top of that, it'll make it easier to completely remove the top set screw to allow adjustment of the bottom one.