fine threads VS coarse threads on set screws...........................

[12bolts]

Thanks for the reply Tony.
and GGV = compacted graphite iron, yes?

Cheers Phil

 

[Thurston Howell]

Hello Tony and All,

I certainly appreciate that concept, 'turning it too hard', and no question have been quilty but the more common problem with me is not keeping the tap aligned and square!

Recently picked up a hand-tapper that was in rather poor condition from sitting in an unheated, wet garage for a few years - covered in rust. Some careful electrolytic rust removal and elbow grease transformed this ugly duckling into a useful tool (sorry I don't have any before photos)



The two matched Starrett V-blocks/clamps were included with the tapper and also experienced the electrolysis rust removal - came out darn good considering! I later did a heat-bluing on them just for cosmetics. They are on the left with another untreated set on the right for comparison.



With this setup keeping the taps square is a breeze and all I need to do is make a few more holders for the various sizes of taps.

(BTW - I got the tapper and V-blocks locally for $25! Life is good!)

 

[llarson]

A solution I've used to counter constant vibration-loosening of coarse threads in mtls. that aren't suited to fine threading is to coarse thread in, and pin, an insert with a fine thread in the inside.