how to use a thread file

[Bruce Turner]

There must be someone that uses a thread file

 

[bonneyman]

I've got a couple. Rarely did they work on steel bolts, but I had alot of plastic fittings on drain pans that would have been a pain to replace (or a long wait time) that the tools got me through. I think they'd work good on brass and aluminum fittings, too.

 

[OccupantRJ]

Welcome.
That would be me.
On a square thread file the numbers on it are the various thread pitches available to use. Physically place one side of the file to the threads until they properly match. Once matched, push the file across the threads to correct damaged areas of thread. Push forward only, not a sawing back and forth action.

 

[WILD-BILL]

They aren't made to cut threads (in case you weren't aware). They are made to reshape existing damaged threads. I typically would lock the head of the bolt (if loose) in a vise and work the damaged area. Rotating as needed to clean the entire thread diameter.

They work, But man is it a slow painstaking process

 

[Private Lugnutz]

^ What @OccupantRJ and @WILD-BILL said.

Only two things I would add.

I often do much better using a thread gauge, rather than trial and error with various sides of a thread file, to get the right pitch. I find the thread gauge blades to be a cleaner more viewable fit than the teeth on the file.

I've had good results with thread chasers (dies, or restorers), too.

 

[bmwrd0]

Die style chasers are good, but only on standard pattern bolts. If you have anything with an odd size/TPI, such as 1-1/4 12, then you are SOL, and that is were thread files shine.

 

[Private Lugnutz]

Yup.

 

[jumbojak]

I've always had much better luck with triangle files. Thread files never seem to do much of anything for me.

 

[RTM]

I like to start gently, trying to push first rather than cut, but take 2-3 passes to get it right. I do lots of work on old WW tools, and weird thread sizes are the norm.

Another good tool is a Japanese saw Feather File. Can be used to cleanup a single thread at a time, which can make the thread file work easier

 

[OccupantRJ]

I've always had much better luck with triangle files. Thread files never seem to do much of anything for me.

I sometimes start with a triangular file to get a boogered area partially corrected, then switch to the thread file to finish up and blend.

 

[cherrybomb]

I like to start gently, trying to push first rather than cut, but take 2-3 passes to get it right. I do lots of work on old WW tools, and weird thread sizes are the norm.

Another good tool is a Japanese saw Feather File. Can be used to cleanup a single thread at a time, which can make the thread file work easier

Pictures and where did you purchase?

 

[Renegade1LI]

I have better luck using a hss die, but occasionally will use a triangle file.

 

[FrankLee]

These are really nice too.


I also have a couple files and a few chasers, but I normally use dies. Every style is situational though.

 

[zimman]

I don't normally have to repair thread pitch, depth and angle but when I do, I just run a nut down on it at 17,000 rpm and 1500lbs of torque.
Zim

 

[larry4406]

These are really nice too.


I also have a couple files and a few chasers, but I normally use dies. Every style is situational though.

Frank - I have never seen those. What are the called and who makes them?

 

[FrankLee]

Frank - I have never seen those. What are the called and who makes them?

Those are NES thread repair tools; #1 and #2.

 

[john.k]

Reforming the threads often makes a lot more sense than cutting steel away in expensive components ........not hitting threads with a hammer is the ultimate cure

 

[Ohio Andy]

When I need to repair threads, I have had decent luck using the files, but first I usually use my rethread kit.

Amazon.com

The kit comes with two thread files, and I added one or two more into the set. If I'm using the thread file then the other method isn't working. And yes, I have also used a triangle file.

The set linked above is made in the USA

CTA Tools 8240 Universal 53-Piece Rethreading Set​

 

[RTM]

Pictures and where did you purchase?

Here is someone’s image when I talked about these previously.

Traditional sharpening auger bit

I have an old tutorial I made years ago. It's all very simple, but the rule of thumb is that if you do it (probably on old, used auger bits), choose only bits in good condition, with intact side cutters, the screw intact, clean them thoroughly, and finally, the side cutters must be able to cut a...

www.garagejournal.com

Many good WW stores have them

Japanese Saw Feather-Edge Files - Lee Valley Tools

www.leevalley.com

Japanese Feather Files

Japanese Feather Files sold at Highland Woodworking.

www.highlandwoodworking.com

Not something I see at Ace, HD, or Lowes

 

[Wamsutta]

Welcome.
That would be me.
On a square thread file the numbers on it are the various thread pitches available to use. Physically place one side of the file to the threads until they properly match. Once matched, push the file across the threads to correct damaged areas of thread. Push forward only, not a sawing back and forth action.

I'm the only guy in the world who knows how to do that.

 

[OccupantRJ]

I'm the only guy in the world who knows how to do that.

Be careful, DEA is always looking to get the kingpin pusher man!

 

[OccupantRJ]

I don't normally have to repair thread pitch, depth and angle but when I do, I just run a nut down on it at 17,000 rpm and 1500lbs of torque.
Zim

I assume that would be more than 3 ugga-duggas.

 

[Lassen Forge]

Working on really old equipment with oddball threads/diameters that don't match the current conventions of SAE/USS/etc. a thread file is a lifesaver, as you may not be able to find a bolt to replace one, or a correct tap to make a replacement.

When I use them - I set up the work and file so I'm drawing it toward me - I just feel I have more control that way.

 

[mikey03]

They come in the tread cleaner tap and die kits and idk what they do or how they work. the idea that if the outer diameter of the bolt don’t fit one of the dies then you can use this makes sense but honestly I never seent any weird thread pitch on anything I work on. But if I do then now I got an idea to do something

 

[RTM]

Useful for More than just odd thread sizes. Sometimes the threaded end is fouled up, and a die won’t start. The file can be used to start from the undamaged area of the shaft, and work to the tip, allowing the die to clean up after.

 

[jkesselr]

I assume that would be more than 3 ugga-duggas.

I believe the proper spec is 7.438691 ugga-duggas. The variable speed trigger comes in clutch here...

 

[OccupantRJ]

They come in the tread cleaner tap and die kits and idk what they do or how they work. the idea that if the outer diameter of the bolt don’t fit one of the dies then you can use this makes sense but honestly I never seent any weird thread pitch on anything I work on. But if I do then now I got an idea to do something

I have encountered some strange ones before I retired. A memorable one was a proprietary .767-27 thread.

 

[cherrybomb]

Here is someone’s image when I talked about these previously.

Traditional sharpening auger bit

I have an old tutorial I made years ago. It's all very simple, but the rule of thumb is that if you do it (probably on old, used auger bits), choose only bits in good condition, with intact side cutters, the screw intact, clean them thoroughly, and finally, the side cutters must be able to cut a...

www.garagejournal.com

Many good WW stores have them

Japanese Saw Feather-Edge Files - Lee Valley Tools

www.leevalley.com

Japanese Feather Files

Japanese Feather Files sold at Highland Woodworking.

www.highlandwoodworking.com

Not something I see at Ace, HD, or Lowes

Thanks,I have the Lee Valley catalog,there a great company to do business with.

 

[AEAdam]

When the first thread is damaged, and I find that more often than any other thread damage, using a thread restoring or thread cutting die, would likely cause more harm than good. When the first thread is messed up, that can cause you to cross thread good threads.

Thread files excel at fixing first couple threads

 

[zimman]

I assume that would be more than 3 ugga-duggas.

While holding the bolt with a pair of vise grips. LOL
Zim

 

[cherrybomb]

When the first thread is damaged, and I find that more often than any other thread damage, using a thread restoring or thread cutting die, would likely cause more harm than good. When the first thread is messed up, that can cause you to cross thread good threads.

Thread files excel at fixing first couple threads

Agreed, and at my age a magnifying glass and a small triangle file is where I start

 

[decableguy2000]

While I have thread files, I tend to struggle with them. I have split rethread dies and you run from in to out on the studs. I use traditional rethread dies for clean up duty mostly.

 

[Private Lugnutz]

^ If by "clean up duty" you mean light burrs and mashing, I agree. If I can't even get the die started the fastener is probably too boogered. I might try a thread file, then run the chaser. But neither thread files or chasers are true "re-threaders" or "thread cutters" in my experience.

 

[captain14]

These are really nice too.


I also have a couple files and a few chasers, but I normally use dies. Every style is situational though.

I have the craftsman version I bought years ago when Sears was pushing them. Used it once and it paid for it self when I damaged a thread on the mower engine while replacing the key.

 

[545_days]

The biggest mistake using thread files is rushing the job because you are pissed that the thread is damaged in the first place.

Taking my time and working slowly seems to be key for me to get the best results. Don't try to fix bad threads quickly with aggressive cuts as that is a sure fire way to make things worse.

 

[richfinn]

Select the correct thread pitch (stamped on the file) and then start filing across the damaged area of the thread at a 90 degree angle.

It's tedious but will get you out of a jam.

 

[AEAdam]

Select the correct thread pitch (stamped on the file) and then start filing across the damaged area of the thread at a 90 degree angle.

It's tedious but will get you out of a jam.

(adding more to Rich's post)

I use the good threads to index the file to. You need to set the right helix by eye and by feel. I tend to start with my file in good threads and push it into the bad threads. The idea is to straighten them. If you rush into the bad areas, your file skates across the bad threads and makes a mess.

If the threads are messed up circumfrentially, I move the file up into the good threads then slowly turn the screw to just start touching the first bad thread and I work my way down into the misthreaded region.

Many many times for me, the screw threads are either completely shot or easily fixable. Maybe this is something each of you needs to learn i.e. when you can use a thread file or rethreader, and when you can't.

I can say it doesn't take much damage to make a screw difficult to use. Just one tiny area of damage on a single thread can do it. This is precisely why people have these files and use them. 30 seconds with the thread file often does the trick.

Thread files are also pretty effective at cleaning away rust and debris.

 

[dscheidt]

it's also much more difficult to remove too much material with a thread file than with a triangular or other more common file.