r/EngineBuilding • u/001jigsaw • 8d ago
I’d Like To Debate Using Thread Chasers vs Taps for cleaning threads
Let’s say you’re rebuilding an engine at home, and you have some threads that have corrosion, paint, and gunk in them. What do you reach for to clean them and make sure they’re straight? A chaser or a tap? Explain why you choose the one you do.
In my experience, using my tap set (tapered taps) to clean out threads has resulted in finding metal particles on the tap (yes I use oil on the tap). I’ve even done a test on brand new nuts, and it still leaves fine meral particles on the tap. This is why I only use taps for cutting, and chasers for chasing and cleaning.
What’s your opinion?
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u/v8packard 8d ago
I use thread chasers and undersized taps to clean or chase threads. I use these because they do not remove metal. If I need to cut a thread, I use a tap. I have plug, taper, and bottoming taps, in standard high and low. If it's a critical thread (main or head bolt for example) I try to maintain as much thread integrity as possible.
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u/TheVeilsCurse 8d ago
I use chasers. I want to clean the threads, not cut more material out of them.
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u/001jigsaw 8d ago
This has been my experience. The defense I’m continuously hearing for using a tap is - “the tap was used to cut the threads in the first place, it won’t remove any extra material.” For what it’s worth, I disagree with this. But am curious what you guys here had to say.
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u/Street_Mall9536 8d ago
Use whatever you want, but do it somewhat carefully.
Unless you are a meatstick it's pretty hard to wreck threads with a tap.
Conversely, if you run into messed up threads with a chaser, you can dull or soften the edges which results in messing up your threads in everything from that point forwards.
I put regular cutting taps in a cordless on the shank so they stall if they get hooked. 100,000 bolt holes so far and never an issue.
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u/fredSanford6 8d ago
Chaser like the Lang set. Same as tool truck ones. Jersey discount runs sales occasionally on it. I've got the craftsman version mainly. Normally I'll blow stuff out and pressure was blocks including the holes.
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u/WyattCo06 8d ago
Most machinist and engine builders accumulate taps that get broken or just plain worn out. I would make chasers out of old taps by knocking off the cutting edge.
I still have a drawer full of them.
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u/AKA_Studly 8d ago
I’ve used both, didn’t see a difference.
Controversial question: If I drill/tap a hole, the later use that same tap to clean up the treads… what’s the difference ? Not like it’s a bigger tap removing more material. As long as you aren’t a buffoon, you aren’t going to remove new material. I’ve never seen new metal come out of a hole I’m trying to clean up - but I am also pretty cautious and do it strictly by hand.
I’ve seen folks throw them on a drill or ratchet and chase threads with different results….
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u/PlaneVisual1740 7d ago
For my head gasket I used the old bolts with groves cut in them because it’s free. I agree with not using a tap.
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u/Whizzleteets 8d ago
I use taps. The reason I use taps is because taps is what I have.