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Backyard mechanic taps

Bluechipx

Hot Rolled
Joined
Dec 29, 2008
Location
W. Mich
I have a friend that works on jetskis that 'tried' to bring me up to date on a great way to fix damaged threads. He proudly said that taking a bolt or stud and cutting flutes into it with a cutoff wheel works better than a tap for restoring damaged threads. He wanted to demonstrate it to me in my shop. I was a little insulted and refused to let him show me. Modern taps have evolved into engineering masterpieces with a wide choice of materials and an almost limitless amount of design features. To cast all that aside and see his demo was insulting. To think that a blob shaped burr on a bolt or stud should even be taken seriously, so I just shook my head and flatly refused to see his demo. Would you have let him proceed or do what I did?
 
I think it's pretty hard to get damaged INTERNAL threads. :-) Now external ones are something else.
...lewie...
 
It's a very old school method of cleaning tapped holes, from things like rust or gasket cement, .......done it more times than I care to think off.

As to damaged internal threads - if it works for you - why not?
 
I have a friend that works on jetskis that 'tried' to bring me up to date on a great way to fix damaged threads. He proudly said that taking a bolt or stud and cutting flutes into it with a cutoff wheel works better than a tap for restoring damaged threads. He wanted to demonstrate it to me in my shop. I was a little insulted and refused to let him show me. Modern taps have evolved into engineering masterpieces with a wide choice of materials and an almost limitless amount of design features. To cast all that aside and see his demo was insulting. To think that a blob shaped burr on a bolt or stud should even be taken seriously, so I just shook my head and flatly refused to see his demo. Would you have let him proceed or do what I did?

"Neither" work for yah?
 
I can see this as an advatage..for some...

New taps cut very well and in wrong hands could wipe out a slightly damaged thread by a miss start as it could start cutting before in the existing thread.

A modified bolt will not likely cut worth damn but the grinder slot can scrape out crud and maybe some odd stuff.

Jet ski means alloy motor that threads could easily be damaged by same backyard skills and a good tool in their hands could do more damage than poor one.

Cheap import taps are good here as they are usually not that sharp and not as hard so less likely to break in the hole.

Correct tool is thread chaser..

Sent from my SAMSUNG-SM-G930A using Tapatalk
 
It's a very old school method of cleaning tapped holes, from things like rust or gasket cement, .......done it more times than I care to think off.

As to damaged internal threads - if it works for you - why not?

Just for a change I agree with you.
 
It's a very old school method of cleaning tapped holes, from things like rust or gasket cement, .......done it more times than I care to think off.

As to damaged internal threads - if it works for you - why not?

Amen. I would have let him, and then informed him that it is an old technique when proper taps are not available. I've been there, done that.
 
When I was still wearing short pants, Dad taught me that whenever I cut off a piece of threaded rod or screw etc. to always run a nut down below the cut. When you take off the nut it straightens the threads enough to get the nut back on. I own plenty of dies, but still follow dad's instructions, er, maybe with a trip to the grinder before I take the nut off.
Kind of the same idea.
 
I would let him proceed on his own demonstration part... But obviously a whizzed-up bolt isn't going to work as well as a tap for repairing damaged threads. For cleaning only it should work just the same for the most part.
 
As stated the bolt contraption has a chance of displacing the threads back to their original location which can be superior to cutting out the displaced material.

Commercially available thread chasers have been available for a long time. It's kind of like filing off a ding on a corner. Often I will try to peen some of the material back where it belongs cause once you cut it, it's gone forever.
 
I have done this, with success.
I have also split a nut, and clamped it on a stud to clean up external threads.
 
Not sure how or where this becomes insulting?

Cut it with an endmill and get some nice sharp edges :)

Oh, what if you don't have a tap but you have a cap screw and you must get the job out today? Much cheaper and faster than running out to get something lol. Keep your eyes and ears open, never stop learning...stay hungry or go hungry.
 
It's an old mechanics trick. Years ago, when working as young mechanic,on many engines (with flat heads), we would quickly grind a small notch on each headbolt. This would clean out any bit of gasket shellac or dirt that we would encounter.

JH
 
I think what he was actually doing was making a homemade thread chaser rather than a tap. A thread chaser tends to push the metal back into place as much as it cuts. I have a couple of commercially made sets and I use them rather than a cutting tap when trying to salvage damaged threads.

I have also done the grooved bolt trick for odd sizes.
 
Done it many times myself, but only with a decent quality bolt.
Seems a GR8 modified bolt a little more forgiving than a worn HF tap that's ready to snap.
I have an assortment in my toolbox at home
As mentioned above, displacing material "back to where it was" is sometimes better than cutting out the nuggets, Along with the bolt diam is smaller than the tap, may just be the extra material needed to hold that trailer hitch on the frame.....
 
It's a very old school method of cleaning tapped holes, from things like rust or gasket cement, .......done it more times than I care to think off.

As to damaged internal threads - if it works for you - why not?

It's not a very elegant solution but it's often better than nothing. If you're working on a farm or ranch 50 miles
from town and the baler goes down and you've got 40 acres of hay laying on the ground and it's threatening
rain you do what you have to do to get the machine running again. Been there done that more than once.

It's nice to have "standards" but if you're a young guy who's always worked in a nice, well equipped shop you
have no idea what it's like when the pressure is on and things just need to "work".
 
It's not a very elegant solution but it's often better than nothing. If you're working on a farm or ranch 50 miles
from town and the baler goes down and you've got 40 acres of hay laying on the ground and it's threatening
rain you do what you have to do to get the machine running again. Been there done that more than once.

It's nice to have "standards" but if you're a young guy who's always worked in a nice, well equipped shop you
have no idea what it's like when the pressure is on and things just need to "work".

Exactly, aka the difference between ''what the book says'' and real life.
 








 
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