View Full Version : How to use a Tap??

04-13-2004, 06:48 PM
I am going to use a tap for bolts going into the transmission, where the mounts attach. Is a tap hard to use? how do I get the filings out of the hole before putting a bolt in? do I need to keep oil in the hole while using the tap? That maybe hard since the trans is in car. I have two taps
5/16-18 and 5/16-24, which should I use? will this be hard to do on the transmission case?

Thanks for the advise.


04-13-2004, 07:30 PM

ok taps are not bolts. i hope you mean you plan to chase the holes with a tap to clean out the threads.
use the tap that is the same size as the bolts. big difference in 18 tpi(coarse) and 24 tpi(fine).

to keep chips out of places they dont belong , you can use wheel bearing grease on the tap and go very slow. a turn or two and then clean the tap. the grease will hold the chips.

a tap is fairly easy to use Go Slow. take your time. if your just chasing holes (ones that are already threaded) the tap should start fairly easily. if it binds or doesnt seem straight STOP. find out why before you continue.

when tapping a New hole . the proper size drill should be used 5/16-24 is a .272 drill and a 5/16-18 is a .257 drill. Be sure to chamfer the hole with a counter sink just enough to break the edge and slightly larger than the tap size. a good way to make sure you start the tap straight is to use a tapping block. nothing more than a square chunk of steel with a clearance hole for the tap. thick enough to hold the tap straight but thin enough to let you at least get the tap started 3-5 turns or more. work the tap in a turn at a time, then back it off two turns, this breaks the chip and makes tapping easier. if the tap stops or binds. Stop and find out why

you do not need to flood the area with oil but some form of lube should be used. motor oil would work. compressed air used carefully can help remove the chips

i am not sure just what you are doing. but be safe use eye protection. a tap can shatter if hit with a hammer.

hope this was helpful



04-13-2004, 07:39 PM
also remember to reverse the tap about half a turn every two or three threads which clears the cutting area

04-14-2004, 09:43 AM
Hold the tap in your left hand and a wooden mallet in your right (if right handed). Make sure the keg is on something sturdy or the floor....wait a minute....are we talking about the same thing?

04-14-2004, 07:38 PM
When using the tap only go as deep as the threads. If the tap binds back it off to clean the threads. Watch the eyes metal shavings can be painful.