question on stripped out bolt holes

[spstan]

If a person (like myself for instance) strips out the threads of a bolt hole by applying too much force, is there an easy way to repair this goof? Most of the videos I've seen on You Tube involve drilling and tapping to make new threads for the bolt.
I was wondering if it were possible to put epoxy (like JB Weld) into the bolt hole, screw the bolt in and let it dry. I'm thinking maybe this would mold some new threads in the bolt hole. Then I unscrew the bolt, put on the plate I'm attaching and then screw the bolt back in. Would this work or do I give up on this idea? Paul

 

[Triple Pickle]

That simply won’t work. You have to do it the hard way. Which might not be as bad as it seems.

 

[mrfury68]

Don’t do the JB weld. That would, in a sense, weld the bolt in place. If the threads aren’t totally stripped out you could get a thread restorer set. These do not cut new steel threads as a tap or die would but they “clean up” worn or scuffed up threads. They have bailed me out a few times over the years. Good luck.

 

[spstan]

Don’t do the JB weld. That would, in a sense, weld the bolt in place. If the threads aren’t totally stripped out you could get a thread restorer set. These do not cut new steel threads as a tap or die would but they “clean up” worn or scuffed up threads. They have bailed me out a few times over the years. Good luck.

Fury; I saw a guy on YouTube (sixty five ford) and he claims if you put a few strands of thin copper wire down the sides of the hole and then screw the bolt in, the bolt will attach securely. Anyone try this? Paul

 

[volksworld]

any effort to squash something inside the hole in hopes of the bolt jamming itself in there will not hold original torque and could crack whatever you're threading the bolt into....loctite makes form-a-thread which is some sort of epoxy thread restorer although i've never used it myself...let's start with "what exactly did you strip?"

 

[spstan]

Fury; I saw a guy on YouTube (sixty five ford) and he claims if you put a few strands of thin copper wire down the sides of the hole and then screw the bolt in, the bolt will attach securely. Anyone try this? Paul

Fury; do you have a brand name for that thread restorer kit? will it work on aluminum? Paul

 

[Triple Pickle]

Heli-coil.

 

[spstan]

any effort to squash something inside the hole in hopes of the bolt jamming itself in there will not hold original torque and could crack whatever you're threading the bolt into....loctite makes form-a-thread which is some sort of epoxy thread restorer although i've never used it myself...let's start with "what exactly did you strip?"

Volks; I hate to admit it but I had the front bowl of my Holley carb off and on so many times to adjust the float that the last time I think I stripped 3 out of 4 of the bolt holes that hold the bolts that attach the front bowl. I put in some similar bolts from an old carb and they seemed to hold better but I haven't checked for leaks.

Maybe if I send it to Holley they could repair it. The old Holley looked like it had a steel body but this newer one looks to be made of aluminum. Paul

 

[mrfury68]

I can’t recall if I ever used one on aluminum. Aluminum is a soft, porous metal that would need heli-coiled. You can Google thread restorer set to find where you can find one to purchase. If you do a decent amount of wrenching this is a good tool to have at your disposal.

 

[CBODY67]

"Pot metal" rather than steel. Then a cad coating for protection and color. You can buy replacement bodies from Holley direct. Check to see if your carb model is in there. The bodies wil be bare so you'll have to transfer parts from the existing carb. OR . . . $400+ will get you a new replacement carb or a Street Demon (with the phenolic float bowl).

As small as those bowl bolts are, probably not much chance of doing the heilcoil fix or similar. Used to be that putting some steel wool around the bolt and then putting it in the hole would be a temp fix for worn threads.

To prevent such wear, next time, you might use a drop of motor oil on the threads and only enough torque to seat things snugly. Let the gaskets do the sealing rather than more torque.

CBODY67

 

[Triple Pickle]

Aren’t Holley carb floats adjustable without taking the float bowl off?
What model Holley is it?

 

[rags]

as a Hail Mary suggestion, if there are any threads left in the bottoms of the holes, get a length of threaded rod in the correct thread size and make studs to go in place of the screws. use flange nuts to seal the gaskets. being aluminum, the holes might be tapped to the next size up.

 

[Big_John]

A quick "how to" for using Heli-Coils. Not a carb, but the principal is the same.

Road Wheel Thread Repair with Heli-Coils

 

[rags]

a quick search for 10-32 heli-coil and it's available so they do have smaller sizes. i cheat like crazy heli-coiling aluminum. if the hole is bad i'll just run the heli-coil tap right in.

 

[Gerald Morris]

as a Hail Mary suggestion, if there are any threads left in the bottoms of the holes, get a length of threaded rod in the correct thread size and make studs to go in place of the screws. use flange nuts to seal the gaskets. being aluminum, the holes might be tapped to the next size up.

Yes, I would recommend tapping to the next size up. Use a GOOD, AMERICAN OR NORTHERN EUROPEAN FORGED TAP also for this job. Chinese or worse (Indian) taps are worse than useless, as they will snap off in the hole one is attempting to save.

 

[rags]

Chinese

i bought a ten dollar set of chinese metric taps and dies at a flea market to use as thread chasers at home. i have real taps and dies for all the more common metric sizes but i'm too cheap to buy a complete good set for the house. so far i have used them as intended with good results. i'm an old hand of course and experience counts.

 

[CBODY67]

Aren’t Holley carb floats adjustable without taking the float bowl off?
What model Holley is it?

Not universally so, especially on non-"race bowl" carbs. I believe the OP stated it is a 4175 spreadbore?

 

[Big_John]

a quick search for 10-32 heli-coil and it's available so they do have smaller sizes. i cheat like crazy heli-coiling aluminum. if the hole is bad i'll just run the heli-coil tap right in.

I've used Heli-Coils down to 2-56 on a regular basis. One place I worked used them by the thousands and a lot of their product was spec'd to have Heli-Coils in mounting holes. IIRC, it was a government spec for aircraft use. I would occasionally do some prototype work as part of my toolmaker/modelmaker position.. and occasionally repair various stuff that had stripped holes etc. They also spec'd a "locking" Heli-Coil that had one coil bent flat to grip the screw. If you see red Heli-Coils, that is a locking type.

A Heli-Coiled hole is stronger than a tapped hole and much more durable. If you cross thread a bolt into one, it's not pretty...

You can sometimes get away with just using the tap on aluminum, I don't suggest it though. Break a Heli-Coil tap and you could be screwed... Although they do make a double Heli-Coil deal for such occasions, but they are tough to find and expensive.

 

[Big_John]

If a person (like myself for instance) strips out the threads of a bolt hole by applying too much force, is there an easy way to repair this goof? Most of the videos I've seen on You Tube involve drilling and tapping to make new threads for the bolt.
I was wondering if it were possible to put epoxy (like JB Weld) into the bolt hole, screw the bolt in and let it dry. I'm thinking maybe this would mold some new threads in the bolt hole. Then I unscrew the bolt, put on the plate I'm attaching and then screw the bolt back in. Would this work or do I give up on this idea? Paul

Fury; I saw a guy on YouTube (sixty five ford) and he claims if you put a few strands of thin copper wire down the sides of the hole and then screw the bolt in, the bolt will attach securely. Anyone try this? Paul

Both of those are extremely bad ideas.

Volks; I hate to admit it but I had the front bowl of my Holley carb off and on so many times to adjust the float that the last time I think I stripped 3 out of 4 of the bolt holes that hold the bolts that attach the front bowl. I put in some similar bolts from an old carb and they seemed to hold better but I haven't checked for leaks.

Maybe if I send it to Holley they could repair it. The old Holley looked like it had a steel body but this newer one looks to be made of aluminum. Paul

I don't know what new Holly carbs are made of... All the old ones are a zinc rich diecast, sometimes called "pot metal". They may be doing a cast aluminum, but I doubt it.

If you stripped 3 out of 4, you are doing something wrong. Either you are cross threading (getting the screw started crooked) or overtightening the bolts. If there is resistance to turning in the screw, you are doing something wrong. Bowl screws are just to be snugged firmly, not cranked on. Too tight and you start causing all sorts of issues with warping the main body or the bowl.

 

[Big_John]

Yes, I would recommend tapping to the next size up. Use a GOOD, AMERICAN OR NORTHERN EUROPEAN FORGED TAP also for this job. Chinese or worse (Indian) taps are worse than useless, as they will snap off in the hole one is attempting to save.

Not a good idea in this case.

The screws for the float bowl on a Holley not only hold the float bowl on, they have to seal to the float bowl itself. Small washer type gaskets are under the head. You make it oversize and now you have to get the screw head to seal, you'll have to drill a larger hole and counterbore the float bowl for a larger sealing washer. The screw will need a flat sealing surface and then there's the gasket.