stripped cyl head bolt top right side on a 4hp 1973

[crosbyman]

did NAPA a couple of industrial tool shop etc… not in stock at 1/4-20 (must be a popular size..)

one shop asked $115 cdn (incl. taxes) for the small kit !!!! 🙁 with a few 1/4-20 inserts.. same HEli-coil kit on AMazon was $36 🙂 so I will go Amazon and wait it out for a saving of $64)

The kit insert coils were about 3/8 can I insert 2 back to back to fill with a longer coil rather shopping around for 1 inch inserts .. there is enough room in the PH holes for almost 1 inch long inserts

https://www.amazon.ca/-/fr/Helicoil-5521-4-r%C3%A9paration-filetage-%C3%A9pais/dp/B0002SRE8Q/ref=sr_1_8?__mk_fr_CA=%C3%85M%C3%85%C5%BD%C3%95%C3%91&crid=24K94RRK57AZ8&keywords=helicoil+1%2F4+-20+inserts&qid=1640122993&sprefix=helicoil+1%2F4+-20+inserts%2Caps%2C94&sr=8-8&language=en_CA#customerReviews

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[frankr]

To answer the question, you can install two of them back to back, just leave a bit of space between them so you can break off the tang of the outer one. BUT there is absolutely no reason for putting in two of them. One 3/8″ long one is more than adequate for a 1/4-20 bolt. In fact, a 1/4″ long is plenty. Screw it down to about 1/2 thread below the gasket surface.

[crosbyman]

ok great thank you very much for the guidance

p.s. tried to buy local (big trend these days) but this shop asked $100 and taxes for a 36$ package. Wiling to help local dealers but not get fleeced … 🙁

Best wishes for a Merry Christmas and a Happy new year 🙂

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[billw]

Make sure you compare apples and apples, as far as how many inserts you get in the kit. It can vary. McMaster Carr has them. Interesting prices: 1/4″ and 1/2″ lengths are $61 for a kit of 10. 3/8″ length is $43 for a kit of 10. Weird.

Long live American manufacturing!

[crosbyman]

Keep in mind I am in Canada and free trade stops at the border 🙂 plus the exchange rate 🙁 plus 15% in taxes……. 🙁

I ended up choosing a kit from EZ lock at 41$ cdn ….e/w drill , punch, 10 SS inserts installation tool

https://www.amazon.ca/gp/product/B0092QTTTQ/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

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[sutterhome]

aliexpress has some too

[necks]

Thats a good video, the only thing he left out is make sure you remove the tang after you break it off. I agree with Frank, Heli-Coil inserts are the only way to go, thats all I ever used, never had a problem. When you buy a set get the various lengths the coils are used. I was taught back in the day, whatever size bolt thickness is used like 1/4-20 the heli coil being inserted must reach down at least 1/4 inch, I always went one size longer, in other words threads should’nt have to be any deeper than bolt thickness for maximum strength.
Another thing I noticed on video nothing was clamped down, he was holding vise with hand,
1) Make sure table you are using is level
2) Vise is great make sure piece part is level and square with drill press, use level or indicator, clamp vise and part to table so it doesn’t move, remember you got one time to get that heli-coil in the correct spot, takes a little more time but worth it in the end
3) I always used a lot of oil with this job
4) Make sure you have enough travel for drill chuck after tools are installed
5) They make a tool that fits on top of tap that also goes into chuck, so when you start to thread ,it will be going in straight
6) Have fun

[crosbyman]

my as well have this handy if anybody needs it 🙂

http://www.noblefix.com/helicoil/HeliCoil-Drill-Chart.html

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[crosbyman]

update…. JAN 02….received my EZ TOOL to drill tap and screw in an insert 1/4-20

piece of cake ! easy as pie 🙂

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