size drill & tap for hellicoil

[reeldutch]

i took the headcovers off from a v4 cylinderhead and 2 bolts broke off and need to be drilled out.<br /><br />what size drills do i have to use and what size tap<br />and hellicoil.<br /><br /><br />thanks reeldutch

 

[DHPMARINE]

Re: size drill & tap for hellicoil

reeldutch,I believe the broken bolts were 1/4 x 20 .What you need to do is order a Helicoil kit.It comes with a drill,special tap,thread inserts and a tool to install the inserts.In the future you have the kit,and just buy more inserts. <br /><br />I think you can STILL order them from Johnny-Rude,but a local bearing supply house can do it also.<br /><br />In some cases,because of the over sized drill,for the over sized tap,there isn't enough material there.But I think you'll be OK on this application.<br /><br />DHP

 

[reeldutch]

Re: size drill & tap for hellicoil

thanks Dhp,<br /><br />i found them on ebay<br />is this what you mean<br /> http://cgi.ebay.com/ebaymotors/HELI...ewItemQQcategoryZ63703QQitemZ4612911739QQrdZ1 <br /><br />thanks reeldutch

 

[OBJ]

Re: size drill & tap for hellicoil

Yeah, that's it real reeldutch. You'll need a 17/64 drill for that tap.

 

[reeldutch]

Re: size drill & tap for hellicoil

thanks OBJ

 

[rodbolt]

Re: size drill & tap for hellicoil

reeldutch<br /> the heli coil tap will have the drill size printed on the tap.<br /> the kits can be had at most napa stores.