Helicoil

[kurtis v-8-60]

need to install helicoil for 1/4x20 screw cant find chart for what size drill to use for insert. Help
Harold

 

[1952henry]

http://www.noblefix.com/helicoil/helicoil-drill-chart.html

This work? Looks like an H.

 

[Paul/Woodinville]

According to my chart it is a #7 drill.

 

[Ronnie]

Page 16 tells all.

http://www.helicoil.in/pdf/helicoil catalogue.pdf

R

 

[1952henry]

Sure does. Looks to be the exact chart I posted. Size H drill

 

[Kurt in NJ]

usually the drill size is etched on the helicoil taps---if you have a real tap---you can also measure the diameter of the tap where the first cut of the thread shows and pick a drill that size

 

[GOSFAST]

The recommended drill size included in the 1/4-20 set is 17/64".

This drill measures .2656", the letter "H" mentioned above measures .266" and will work fine in this application also. Most general shops will have the 17/64" available, maybe not the letter series however??

Thanks, Gary in N.Y.

P.S. Hi Paul, the "#7" mentioned above is .201" and is much too small! It is correct for a "new" 1/4-20 hole size.

 

[kurtis v-8-60]

Thanks for your help The H drill is the one