tap and die questions

[shadesh]

Hi,

Can someone give me some measurements here.. I want to chase the thread in the block where the head bolts go but not sure what size tap I would need.

Also, what size die (is that the right term) would I need to clean up the thread for the manifold bolts?

And, I found this tap and die set at harbor freight (item #

ITEM 39384-2VGA). Its a carbon steel tap and die set. Anyone know if these items are durable or should I get a set elsewhere?

Anything else I should be careful about while I am doing this? Any advise will be appreciated.

Thanks.

[shadesh]

anybody?

[geezer]

Any good tap & die set will come with a screw pitch gauge as shown in this pic of my Snap-On Metric set. Using this gauge is the quickest and most exact way to find the number of threads per inch on a bolt or nut. Used for both external and internal threads.

I have had this set for almost twenty years and although lightly used, I have never broken a tap or die yet. The same can also be said for my SAE Hilka set that I have used a lot over the last forty years, so there is something to be said for paying once up front for quality. Then when needed, the correct tap or die will be there, not broken/missing.

[zKars]

Head bolts are 10 x 1.5 mm

Do NOT go cheap on a tap and die set. Excellent advice.

Go buy a 10 x 1.25, 8 x 1.25 and 6 x 1.00 as well for 98% of the other bolts in the car.

Jim

Edited May 31, 2009 by zKars

[Derek]

Harbor freight taps are good for getting the grease out of a hole and that's about it.

Derek

[shadesh]

Thank You everyone. That helps plenty. ... now at least I know what I should be looking for.. this is useful information.

[TVollnogle]

What Derek said. I got a set from Harbor Freight just for chasing threads and they barely do that. The 6 X 1.00 already has the cutting threads worn off and needs replaced. I have a 30+ year old Craftsman SAE set that has served me well.

Edited June 1, 2009 by TVollnogle

[george71z]

I have had a Sears Craftsman metric and SAE set for close to 30 yrs. and it has served admirably. Granted, I think the quality of Craftsman has declined over the years, but maybe you can pick up an older set at a flea market or garage sale. Z137 gave good advice. Do not go cheap on taps and dies.

[70 Cam Guy]

I'll echo everyone else, buy quality for threading. Also use some sort of lubricant when cutting threads and don't forget to break your chips! Removing a broken tap is not an easy task

If you're only chasing threads, maybe find some thread chasers. They don't remove material and they help to reform the thread. Hell even a common roll tap might be good if you're only chasing threads. Also called a 'rethreader'

http://www.mactools.com/product/tabid/120/p-320459-trmset.aspx

These will not cut new threads if that is your intention