Using a tap and die

[BigT-65]

I need to tap out one of the bolt holes and run the bolt through a die to clean up the threads that holds the caliper to the wheel on the rear passenger side. I have never used a die before and want to make sure I am running the bolt through from the right side of the die. Can anyone tell me how to get this right.

 

[Chas]

Look inside the die and there is a taper in the i.d. that guides it into the threads........this is the starting side.....use a light cutting oil and don't force it,let it cut... turn it a quarter turn then back it up a bit, turn it a little further and back it up....repeat until it is free. don't go too far without looking to see if your lined up. take your time and do it right.

good luck and welcome,chas

 

[BigT-65]

Thanks for the help. Also can you tell me the difference between NC and NF?

 

[Chas]

Thanks for the help. Also can you tell me the difference between NC and NF?

National Coarse and National Fine.......its just the two different thread types in standard engineering terms.

 

[Hib Halverson]

I take it we we are talking about caliper mounting bolts.

The hole in the caliper mounting bracket be "cleaned-up" by running a tap through the threads. Lube the tap with engine oil, screw it through the hole then spray the hole with brake clean to remove the chips. This procedure is for fixing slightly damaged or dirty threads, only. If the hole's threads are badly damaged–say an impact wrench was used on a cross-threaded or incorrectly threaded bolt–I advise replacing the caliper mounting bracket or installing a thread insert rather than trying to repair the threads.

I would not use a die to clean up the threads on a damaged caliper mounting bolt. I'd replace the bolt.

 

[BigT-65]

I don't think the threads in the mounting bracket are badly damaged. An impact wrench wasn't used and I don't think they were cross threaded. The bolt is 7/16 20 I guess this is a fine thread. I'm going to work on it this weekend and see what happens.

 

[Toms007]

Sounds like the threads just need a little clean-up. The tap and the die should work out just fine.

 

[JohnZ]

Taps and dies are best used for creating threads where none exist, not for "cleaning up" threads; taps and dies are very sharp, and remove metal while doing their job. For "cleaning up" threads, I prefer "thread-chasers", not taps and dies; chasers clean the crud out of threads without trying to create new threads by removing metal. Removing metal from existing threads weakens the fastener.

 

[65TripleBlack]

Taps and dies are best used for creating threads where none exist, not for "cleaning up" threads; taps and dies are very sharp, and remove metal while doing their job. For "cleaning up" threads, I prefer "thread-chasers", not taps and dies; chasers clean the crud out of threads without trying to create new threads by removing metal. Removing metal from existing threads weakens the fastener.


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What's to be done with female threads that have slight damage to them? Are you saying that running a tap through them to restore them is not an option? Would running a tap through undamaged but dirty threads necessarily remove any metal?

 

[motorman]

Taps and dies are best used for creating threads where none exist, not for "cleaning up" threads; taps and dies are very sharp, and remove metal while doing their job. For "cleaning up" threads, I prefer "thread-chasers", not taps and dies; chasers clean the crud out of threads without trying to create new threads by removing metal. Removing metal from existing threads weakens the fastener.


View attachment 5582

if you don't want to spend the $$$ for thread chasers just take a new correct size bolt an file groves along the the threads on the bolt and use this the clean up the internal threads.

 

[LLC5]

What's to be done with female threads that have slight damage to them? Are you saying that running a tap through them to restore them is not an option? Would running a tap through undamaged but dirty threads necessarily remove any metal?

Thread chasers are your best bet for cleaning up threads, male or female. Running a tap through undamaged but dirty threads can remove some material as taps are specific for cutting threads, how much material is removed would be based on the material composition to be chased, quality of the tool, and how the operator does the work. You can get by with a tap in a low stress area if you are careful, but any fastener with a specific torque value should be cleaned (if possible) with a proper high quality thread chaser.