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Thread Chasers


attworth

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I've been looking around for some thread chasers.

 

I found this thread - http://forums.hybridz.org/showthread.php?t=72944&highlight=%22thread+chaser%22 which led me to the McMaster site. I did a search and came up with - http://www.mcmaster.com/#thread-chasers/=189hxq

 

I'm wondering what I actually need. I've never used a thread chaser. I know what they do, but looking at the pictures, I have no idea what I'll really need to freshen up my motor. I'd like to chase all the threaded holes that I remove things from. I won't be messing with the block, but I will be removing the head, and have already removed the intake/exhaust and all accessories on the motor.

 

This part number (2542A51) is for the combination "internal/external" chaser. Can anybody clarify what those terms actually mean? Or perhaps point me in the direction of what I may need? I'd hate to order something only to find out it doesn't include the sizes I need. I've read through my "How to rebuild" book, but haven't really noticed any direct references to chaser sizes needed.

 

Thanks everyone.

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I was going to pick up this set from sears. It is a pretty decent price and seems to be reviewed well the places I have found it. They are currently out of stock here otherwise I would already have it

 

http://www.sears.com/shc/s/p_10153_12605_00942275000P?keyword=tap+and+die

 

Harbor freight has a full metric set of taps and dies for $12. I am not sure on the quality, but I am sure it would work for awhile.

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  • 2 weeks later...

I have the Craftsman thread chaser kit and it contains many useful sizes, both metric and SAE. I must say that I did accidentally break the M8X1.25 chaser, as they are not nearly as hard or tough as the fasteners that you'd put in the holes. It happened so quickly that I didn't even realize what was going on. Luckily, I was able to replace that one with an ARP chasing tap of the same size. It is much harder than the Craftsman ones, and more closely resembles the taps of the traditional "cutting" variety that are sold so many places. All things considered, the Craftsman kit is pretty good, just be mindful of resistance you encounter when cleaning, and stop the tap if it becomes tough to turn, then clean the hole with a small brush if possible before proceeding.

 

One thing to remember about running taps through existing holes to clean the threads is not to use a cutting tap if it is possible to get the "cleaning" (chasing) variety. The cleaning tap is basically a fastener with vertical flutes cut into its shank that provide room for the dirt and junk that you're pulling out. Cutting taps are so hard and sharp that it's possible to damage the threads you're trying to clean. Just my $.02. Good luck.

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use a RETHREADER to chase holes and push the threads back into shape slowly, and use a TAP to cut new material into the threads.

 

I usually avoid TAP use in holes that need to have the fastener torqued to a certain spec. The way I see it, the bolt's torque is relative to the amount of thread engagement within the hole it is being threaded into, and some threads are a little more aggresive than others. If you TAP that thread, you are effectively removing thread.

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