What's the difference between a plug tap and a taper tap? I need to tap some LS rocker covers, but there is a metal shield below the hole. Or, would a bottom tap be ok to start cutting the thread or use either a plug or taper tap to start and finish with the bottom tap? Thanks.
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tap question
- Thread starter 87GN
- Start date
Robby321
Well-known member
use either a plug or taper tap to start and finish with the bottom tap? Thanks.
Yep
Yep
dacuda
Well-known member
taper used for thru hole,use bottom tap
You won't be able to start the threads square with a bottoming tap. Taper taps are the easiest to get going straight, but a plug tap is ok unless you have tough material like stainless. You use a bottoming tap to get the last 5 or 6 threads at the bottom of a blind hole.taper used for thru hole,use bottom tap
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There are three types of taps in general use: taper plug and bottoming. It has to do with how many partial starter threads there are before the first full thread. Without looking it up if I am off, the taper has has 5-7, the plug has around 3 or 4 and the bottoming has 2-3. It is always easier to start with a taper and necessary in hard material. Sets that do not give you all three for each size give you a plug tap. I it is a good general pupose tap and has sufficient taper to get you started in most cases. The bottom tap does not have enough taper to start a hole. It's only purpose is to follow the plug tap in a blind hole and cut the last few threads to get thread as close as possible to the bottom. If you need to get almost to the bottom and the metal is not too hard, a plug and bottoming will do you but at that point you might as well by the three piece set of taper plug and bottoming.What's the difference between a plug tap and a taper tap? I need to tap some LS rocker covers, but there is a metal shield below the hole. Or, would a bottom tap be ok to start cutting the thread or use either a plug or taper tap to start and finish with the bottom tap? Thanks.
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Wamsutta
Well-known member
Don't try to start cutting threads with a bottom tap.
LumpyMusic
Well-known member
I think those three packs from Amazon (Champion/Irwin brand) are a great way to buy taps. Three GOOD quality taps, all three tapers, for about 20 bucks for the larger sizes. Beats the heck out of the "Every size known to man for $100" sets.
Lump
Lump
You'd be better off taking the oil shield off of the valve cover.
Tap the hole with that shield in place and you WILL trap a chip (or 10) somewhere, that chip WILL work itself loose and once it does it WILL find a way to sneak into a spot where it could wreck the valvetrain.
Do yourself a favor and do it right the first time.
Tap the hole with that shield in place and you WILL trap a chip (or 10) somewhere, that chip WILL work itself loose and once it does it WILL find a way to sneak into a spot where it could wreck the valvetrain.
Do yourself a favor and do it right the first time.
Wamsutta
Well-known member
Make sure you back out a quarter turn after every turn to clear the chips out; otherwise you'll break a tap.
Matt Irvine
Well-known member
If you would rather not get a chip left in the bottom oh the hole, pack the flutes of the tap with a heavy grease, it well help retain most of the chips in the flutes.
If you would rather not get a chip left in the bottom oh the hole, pack the flutes of the tap with a heavy grease, it well help retain most of the chips in the flutes.
Another way is to fill the hole with wax. As the tap feeds in the wax will be forced out carrying the chips with it.
lg
no neat sig line
pendragon1998
Well-known member
Another way is to fill the hole with wax. As the tap feeds in the wax will be forced out carrying the chips with it.
lg
no neat sig line
*added to my bag of tricks