Thread cleanup questions

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Trevor B

Trevor B

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I want to try to clean up the head, intake, and block holes and bolts as much as possible before my re-assembly.

What do you guys use to clean up bolt threads and holes when rebuilding?
Tap and die?
"Thread cleaning tap set"

Can I wire brush my bolts with the wheel or do I need to use brass?

Thanks!
 
For blind holes I use a bottoming tap. They are flat on the end.
 
Tap set for bolt holes and wire wheel on bench grinder for the bolts. Use plenty of penetrant for the bolt holes to make sure and get all of the dirt/metal shavings out of the bolt hole while tapping.
 
JBurch is right!!

Thread cleaning taps and dies won't remove any metal like a regular tap or die will. There's a difference!! Regular taps and dies are for "cutting threads", thread cleaning taps and dies clean the threads.

treblig
 
be sure to blow out any holes you clean out - low-ish air pressure - put a rag over the hole and air nozzle and go easy, you don't want any metal shavings getting away
 
Trevor B said:
I want to try to clean up the head, intake, and block holes and bolts as much as possible before my re-assembly.

What do you guys use to clean up bolt threads and holes when rebuilding?
Tap and die?
"Thread cleaning tap set"

Can I wire brush my bolts with the wheel or do I need to use brass?

Thanks!
Click to expand...

About $40 ('78 $) worth of new bolts with 4 'centerlines' cut through the threads
at the horizontal center line of the bolt(s),

Blind, Taper, Centering, Bottoming taps pitch variance is completely Mfgr
dependent & are all over the place with tolerance ...


Just My personal preference, I want to clean, not re cut.

P.s, $ spent = one time use :)
 
About $40 ('78 $) worth of new bolts with 4 'centerlines' cut through the threads
at the horizontal center line of the bolt(s),

Blind, Taper, Centering, Bottoming taps pitch variance is completely Mfgr
dependent & are all over the place with tolerance ...


Just My personal preference, I want to clean, not re cut.

P.s, $ spent = one time use :)
Click to expand...
More info on your plan please. Sounds promising. Right now I use thread chasing taps and no wire wheel for the bolts, just a wire bristle brush.
 
mech1nxh said:
Blind, Taper, Centering, Bottoming taps pitch variance is completely Mfgr dependent & are all over the place with tolerance ... )
Click to expand...



There are SAE standards for threads to make sure that they are compatible, all manufacturers make them to those standards.
 
Thread chasers are the best. Taps are too sharp and may try to cut new instead of cleaning the old threads. If you brake a chaser it is softer and easier to remove. A tap? Not so much. Use the proper tool for the job. Toolmanmike
 
I've been doing it all wrong for 30 years then. While I have a thread chaser set (mostly for the thread files) I use taps and dies for fasteners and holes.
 
moper said:
I've been doing it all wrong for 30 years then. While I have a thread chaser set (mostly for the thread files) I use taps and dies for fasteners and holes.
Click to expand...


Me too....... guess I have been doing it wrong for 30 plus years also.,.....I just use tap and dies....I mean the diameter and thread pitch size is what it is......as long as you have the correct size, it is not going to cut any "new" threads.....Just clear out the **** and debris that shouldn't be between the threads anyway....and help restore the high spots of the threads....And for blind holes I use bottoming taps....A fool and their money will soon part
 
Yup. if a die cuts new threads in a bolt or stud - you need a new bolt or stud. If the tap cuts new threads in the block, the bore has been distorted of perhaps overtorqued unless you've got some POS set of taps and dies. As krazy said - there are industrial standards and specs for them.
 
THIS - I can't believe there is even a discussion here. Taps and dies are for MAKING threads where they do not yet exists.. thread chasers are for clean up and removing light burs.
toolmanmike said:
Thread chasers are the best. Taps are too sharp and may try to cut new instead of cleaning the old threads. If you brake a chaser it is softer and easier to remove. A tap? Not so much. Use the proper tool for the job. Toolmanmike
Click to expand...
 
some taps, like the smaller sizes have crazy lead in lengths that will never clean the bottom threads of a blind hole. Chasers are like taps that have been cut off: full length threads with a flat bottom. I use a brass wire wheel on bolts, its just what I have but have used a regular wire wheel as the bolts are pretty hard anyway. whatever you use, turn it back and forth so as not to load up the tap and bind it.
 
Snap On makes a thread restorer kit that only costs about $100. It's the best money I've ever spent on tools. There are knock off brands for the $50 range as well. It comes with thread dies and taps and thread files. Everyone should own one of these kits.

View attachment Snap On.jpg
 
Well this is certainly a hotter topic than I expected!
For better or worse, I got the tap and die out yesterday (after about half of the above responses but before seeing the other half) and went through the heads - it didn't really feel like it was cutting but no way to be sure. Used the die on the bolts and they certainly screw in cleanly.

It would be really interesting to do a "snugness test" or something: use a normal cutting tap and die on say, half the holes/bolts and a thread chaser on the other half... and then see if they feel and fit any different.
 
Mopar to ya said:
Snap On makes a thread restorer kit that only costs about $100. It's the best money I've ever spent on tools. There are knock off brands for the $50 range as well. It comes with thread dies and taps and thread files. Everyone should own one of these kits.

View attachment 1714869899
Click to expand...


Right there That is all I use and have only used.. Get your self a set of engine brushes , either from eastwood or Moroso
 
FYI when you put the intake bolts, head bolts back in they need lube from engine oil
Put a little on the bolts before your re-install
 
Mopar to ya said:
Snap On makes a thread restorer kit that only costs about $100. It's the best money I've ever spent on tools. There are knock off brands for the $50 range as well. It comes with thread dies and taps and thread files. Everyone should own one of these kits.

View attachment 1714869899
Click to expand...


Same set I have. I use the thread files all the time out of it.
I also have the Snap On professional tap and die set along with some individual bottoming taps that get much more use. Both were bought when I was still turning wrenches. The chasers are too lose in the holes and not hard enough to truly clean the threads all the way when there's burnt carbon and rust in them (like head bolt holes). At least that was my experience. I think a chaser is better than nothing, but a tap cleans everything out.
 
Trevor B said:
Well this is certainly a hotter topic than I expected!
For better or worse, I got the tap and die out yesterday (after about half of the above responses but before seeing the other half) and went through the heads - it didn't really feel like it was cutting but no way to be sure. Used the die on the bolts and they certainly screw in cleanly.

It would be really interesting to do a "snugness test" or something: use a normal cutting tap and die on say, half the holes/bolts and a thread chaser on the other half... and then see if they feel and fit any different.
Click to expand...


Good Job!...Mission accomplished! And you didn't waste your money...You used what you already had
 
..including the original threads if you're not careful - IF the thread chaser doesn't net a clean hole then go with the tap, but starting with a tap can lead to trouble..miss it by a hair with a tap and you've got a cross threaded hole - now you're drilling and helicoiling.. that's always fun... been there!
moper said:
I think a chaser is better than nothing, but a tap cleans everything out.
Click to expand...
 
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