Tap & Die set

Hi all

I've been advised to tap the threads on my suspension parts. I have just been looking through my Tornado build manual and there seems to be some metric bolts used and also some UNF sizes. The main sizes seem to be M10 metric and 7/16" and 1/2" UNF sizes.

I've not used a tapping set before but I guess it makes sense to buy a set with a good range of sizes as I imagine they will come in handy.

I like the look of this snap on set but I can't find the sizes it comes with. Does anyone have this or a set like it and how good are the snap on sets and would it cover the sizes I need?

RTD48, Kit, Master Rethreading, U.S./Metric



Alternatively I've seen a cheaper set by sealey that has a good range of sizes but I guess the quality won't be as good.

Tap & Die Set 33pc Split Dies Metric/UNF/BSP: Amazon.co.uk: Car & Motorbike



So I guess the question is, will a cheaper set be suitable for what I need or is it worth me investing in the snap on set. Also will both be suitable for tapping the thread sizes I need

Trev
 
Trevor, my humble opinion - dont buy a set as shown, there will be a lot of parts you will never use. Buy the best quality taps you can find for the few threads you will need, get tap wrenches cheap from E bay, thats all you will need. It is very unlikely you will need dies, if you have any damaged thread on a bolt just throw it away and use a new one, dont compromise on that. Frank
 

Ron McCall

Supporter
Trevor,
The Snap-On set pictured is NOT a Tap set. It is a "thread chaser" set. It is made to repair or clean threads that are already there. It is NOT designed to make new threads. If you look closely, there are two black,square "sticks" included. Those are thread files for repairing or cleaning threads on bolts and studs. The others are for holes.
This set is a GREAT addition to your tool box and is fairly inexpensive .
Just wanted you to know the difference.

An actual Tap set is not really designed to clean existing threads. It is designed to make threads in something that has no threads. You would be better off with the thread chaser set as long as you don't have to make any new threads in anything.
 
Trevor, my humble opinion - dont buy a set as shown, there will be a lot of parts you will never use. Buy the best quality taps you can find for the few threads you will need, get tap wrenches cheap from E bay, thats all you will need. It is very unlikely you will need dies, if you have any damaged thread on a bolt just throw it away and use a new one, dont compromise on that. Frank
Thanks Frank

I didn't imagine I'd ever need the dies either but is was more for the taps.

So if I were to buy a couple of individual taps do I need NF? Does this correspond with UNF bolts?

TRT4320A, Tap, Rethreading, NF, 7/16"-20

Trev
 
Thanks guys, just seen your responses.

So really I need a few thread chaser bits and a tool to use them as I am not looking to make new threads just tidy up exisitng threads correct? Is this the type of tool I need or can you just use the chaser bit in and normal socket wrench

YA578A, T-handle Tap Wrench, 1/4"-1/2" taps



Trev
 
Trev:
Most rod ends and linkage are fine thread, the sizes I see most in UNF or SAE are 3/8 X24, 7/16 X20, 1/2 X20, and 5/8 X18, and an occasional 3/4 X 16. In the metric sizes most of the threads are 1.25, or 1.5 MM pitch. The fine threads are stronger, have a better fit. Also the adjustments are finer. I would agree with the the comments above and get your taps as you need them, good ones aren't cheap, and when assembling all of your components use a little anti-seize compound on the parts.
Cheers
Phil
 

Alan Watkins

Lifetime Supporter
Is this the type of tool I need or can you just use the chaser bit in and normal socket wrench
Trev
As Ron says, I have and recommend the Sears Craftsman version of that kit. Where I need more than finger-force to use the tools I just use a small adjustable wrench. No need for a tap wrench since you're probably not applying much force and because achieving alignment at the start is usually not an issue with thread chasing as it is with thread cutting.

Note from the link Ron posted that there is a 48-piece version (vs. 40-piece) of that set that includes tools for the common fine-thread metric threads. You might have to buy that under a different brand than Sears; the mfr. page is 48 Pc. SAE & Metric Thread Restorer Kit


Also, thread chasing as a cleaning operation is critical to establishing proper torque and to ensuring that thread locking compounds will adhere.

However, before you go much further I strongly recommend you acquire a couple thread gauges, one Metric, one English. You need to know for certain what thread you are dealing with before you select the chasing tool. Nothing will ruin your day like using the wrong thread chaser....

In the case of smaller threaded holes you may need to measure the screw that smoothly threads into it as a proxy since the measuring tool may not fit or be usefully visible within the threaded hole.


Example of a typical thread gauge:

Amazon.com: THREAD GAUGE:TM-91600: Home Improvement

Finally, in case you ever do get into cutting your own threads I can recommend the following set (or one like it by Irwin, they have several). These have a good reputation among the DIY crowd , the taps and dies are of reasonable quality for the kind of work we do and cover anything you are likeley to need on a GT40.

117-pc Machine Screw / Fractional / Metric Tap & Hex Die and Drill Bit Deluxe Set - Tools - IRWIN TOOLS

The only individual taps or dies I've had to buy since were either bottom taps because I want straight threads all the way to the bottom of a blind hole (a rare requirement) or to clean up a *really* big thread (12AN fitting).

Just today I bought a set of pipe thread taps but it's the first time I've needed to tap a pipe thread larger than 1/8" NPT, which comes with the Irwin set. 1/2" NPT is common on oil system plumbing.
 
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if you want thread chasers you make them out of HT bolts.
You run them down the grinder to put groves in the thread.
Chasers will never beat a tap.

jim
 

Cliff Beer

Supporter
Ditto what Ron said, the Sears Craftsman taps and dies are high quality and do everything pretty well. Not sure if you have equivalent in the UK there. Personally, I would't spend the extra for the cache of SnapOn.

Frankly, if you do a lot of work with threads then you'll find you use a few taps the most, then less common taps, and then dies once in a while to clean threads. Cutting a thread with this type of die is pretty darn hard - tough to get it straight and centered...you really need a lathe to cut a precise thread in my experience (I do this from time to time).
 

Alan Watkins

Lifetime Supporter
.... Cutting a thread with this type of die is pretty darn hard - tough to get it straight and centered...you really need a lathe to cut a precise thread in my experience (I do this from time to time).
It's easy, just be careful and feel what the tool is telling you. It's all in getting it started square. You don't need a lathe.
 
when ever possible buy the two fluted taps not the four fluted. the two fluted taps are stronger and have a larger recess (flute) to allow the debris to fall out instead of gauling the threads.
 

Cliff Beer

Supporter
It's easy, just be careful and feel what the tool is telling you. It's all in getting it started square. You don't need a lathe.
You've got a steadier hand than I do Alan. I guess I should stop drinking Red Bulls right before attempting to cut a thread by hand.....
 
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