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Some basic questions on how to use a tap/die set.

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GoodEnough

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To back up a bit, how exactly are you supposed to use a tap & die set?

The taps are to re-thread a hole. I get that.
So, you first try to re-thread with the same size and fix the damaged thread?
Then use the same bolt....
Is that right?

If that doesn't work, and you can't seem to fix the damaged thread...
then you tap the next size larger?
This means you need to get a new bolt that is one size larger also?

What if there is just not room to twist that T-handle?
Like if the bolt hole is deep in some recess.
What do you do then? Are there extension bars for these taps?

Also, what exactly is the "die" for?
If it's not meant to be used as a thread restorer.
Do you buy "blank" bolts with no threads...and create threads with the die?
I have never seen blank bolts for sale.
 
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dr_clyde

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Ok...

Taps are used to cut threads where none have existed before. Drill the hole to a specific size, then use the tap to cut the new threads.

It is possible to repair damaged threads with a tap, but it tends to remove material and weaken the threads. There are re-threading taps and dies to clean up existing threads that don't remove material. Worth every penny.

If the threads are damaged beyond repair, depending on the situation, you can drill it out larger and tap the next size up, but you will in fact need a larger bolt.

Dies are the female counterpart to the male tap. You can cut new threads on shafts, rods, extend existing threads, ect. Like taps, there are rethreading dies meant for thread repair, and a regular die is intended to cut new threads.

Charts are commonly available to tell you what size holes to drill for what size taps.

And yes, you can get tap extensions. Very handy. Some tap handles (snapon comes to mind) have a 3/8" female square drive in the back. Just slide the handle out and use a regular socket extension.
 
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MLB0611

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A tap is to create new threads not clean up damaged threads, for cleaning up damaged threads you want a thread chaser. The reason is a thread chaser will follow the current threads of the hole were a Tap may start cutting new threads and unless you are very skilled you may wind up with a bigger mess than you started with:(

A Die is the same made to make new threads on bare stock, like you have to replace a bolt and you need it threaded to the bolt head but you all you have is bolt with a shoulder.

A rethreading kit is much better and will be use more often in a shop the a tap and die kit.

HTH
 
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GoodEnough

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Thanks. Ok, I definitely do not need a tap and die set, in that case.
I am not making anything new. And not making new bolts.

I am doing light automotive work.
To start, I only want something to repair existing threads.
Like if I mis-thread and strip out a bolt hole.
Or to clean up threads of a rusty bolt I am reusing
(Right now, I use a wire brush and some PB Blaster to clean up rusty threads)

I think I just need this, right?
http://www.sears.com/craftsman-48-pc-sae-metric-thread-restorer-kit/p-00942275000P
 
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bob15

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You can use the T&D set to fix or repair threads or make new ones.

Ever have a bolt that doesn't have the thread deep enough? Make more threads. I have made projects where you buy a blank rod and put whatever thread I desire on it (coarse or fine). And yes, i have gotten blank bolts and had our in-house machine shop, make new threads for odd sizes at work (and/or left hand threads).

If I need to make the hole bigger, typically the next size won't work or it won't have enough material for a good thread. For example: 1/4-20 uses a # 7 drill bit and has a major diameter of .2489-.2500. If you plan to drill the 1/4-20 hole and re-tap, a 5/16-18 uses an F drill bit with an OD of .257. this means, not enough material.....use a 5/16 drill bit and tap it for 3/8-16.

as for using a tap handle in tight spots....buy these:

http://buy1.snapon.com/catalog/item.asp?P65=&tool=all&item_ID=635200&group_ID=675369&store=snapon-store&dir=catalog

Oh, and Snappy just sells them.....I believe Liesle makes them.
 
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MLB0611

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GoodEnough said:
Or, can I get away with this?
http://www.ebay.com/itm/METRIC-THRE...538?pt=LH_DefaultDomain_0&hash=item20ce947df2

This is a 7 piece set of metric rethreading taps including: M6x1, M8x1.25, M10x1.5, M10x1.25, M12x1.75, M12x1.5, M12x1.25 .

What does M6x1 mean?
6 means? 1 means?
This doesn't seem to be the bolt head size (eg: 13mm)
Click to expand...

M6 refers to the thread size, not the bolt head size, X1.25 is the thread count 1 is very fine threads, 1.5 is course etc.

Kastar makes most them for Craftsman Snap On etc.
 
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devoncoolman

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6 is the mm size of the thread and the 1 is the thread pitch. If u just want to chase threads then yes your good with that craftsman kit. And if you need to extend threads or thread a new hole i would buy your taps as you need them or just buy a small tap kit.
 
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MLB0611

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GoodEnough said:
Thanks. Ok, I definitely do not need a tap and die set, in that case.
I am not making anything new. And not making new bolts.

I am doing light automotive work.
To start, I only want something to repair existing threads.
Like if I mis-thread and strip out a bolt hole.
Or to clean up threads of a rusty bolt I am reusing
(Right now, I use a wire brush and some PB Blaster to clean up rusty threads)

I think I just need this, right?
http://www.sears.com/craftsman-48-pc-sae-metric-thread-restorer-kit/p-00942275000P
Click to expand...

Yep that will work fine
 
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GoodEnough

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One more thing. What if I misthread a bolt hole, and resort to a thread chaster kit.
How will I know which the right one is? If it's like the bolt, won't it also misthread and not go in correctly? Often you do not know the M1x6 size of the bolt you just misthreaded. How will you now you're using the right sized chaser if the threads are all messed up already , and it's not going in right?
 
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dr_clyde

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Don't forget that if you only need a couple sizes you can buy taps and dies individually from any industrial supply. Way cheaper than a whole set if you're only gonna use 2 or 3 sizes.
 
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MLB0611

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GoodEnough said:
One more thing. What if I misthread a bolt hole, and resort to a thread chaster kit.
How will I know which the right one is? If it's like the bolt, won't it also misthread and not go in correctly? Often you do not know the M1x6 size of the bolt you just misthreaded. How will you now you're using the right sized chaser if the threads are all messed up already , and it's not going in right?
Click to expand...

They are set up to start with damaged threads, thin treads to start out.

As for finding the correct size, match the bolt to the thread chaser, or the bolt chaser, either line up a good bolt to the threads on the thread chaser or thread it into the bolt chaser. most times easy to do than explain.

HTH
 
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ajchien

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I'm going to guess the eBay kit is a smaller version of the craftsman kit, both made by Lang (formerly known as Kastar). They relabel their re threading kits for a lot of brand names.

M6x1 stands for metric, 6mm bolt size,1mm size threads. This should be a 10mm hex head.

1/4-20 stands for a SAE, 1/4in bolt size,20 threads per inch. Usually a 7/16 hex head iirc.

For me, if bolt threads are dirty /paint/grime filled, a wire brush on a grinder works best. A rethreader die works better if the threads are actually mangled.

If you're doing automotive work, consider adding a M18-1.5 for O2 sensors.
 
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GoodEnough

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Just the Ebay "bolts" are $18. The Kastar kit is $70.
It seems like the Sears set comes with "nuts".
Are these worth getting for cleaning bolt threads?
Or does using a wire brush and some lube work just fine?
 
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dr_clyde

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You should get a set of pitch gages and some calipers. Take a 10x1.25 MM bolt for example. The OD of the threads on the bolt is the size of the bolt, in this case 10. Then you use the pitch gages to find the right pitch. Just line up the teeth on the gage to the teeth on the bolt and it will tell you the proper pitch, in this case 1.25. Only use the tap or chaser that matches the bolt.

If you've re-tapped the wrong threads or have damaged the threads beyond repair, get a heli-coil kit of the right size. These only work for a blind hole, though.

If the hole isn't blind and I can get at it with the TIG welder, I'll weld the hole shut, re-drill it and then tap the right threads again. I try really, really hard to make sure I don't have to do this because its a pain in the ***.
 
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MLB0611

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GoodEnough said:
Ok, and "thread size" just means the diameter of the bolt? ...
http://www.wikihow.com/Read-a-Screw-Thread-Callout

Do most cars use industry standards like these 7 chasers?
Click to expand...

Yes the diameter of the bolt is correct.

Not 100% coverage but what you will need most of the time. I have the larger Snap On set and the only time I have run into a problem was on the hold down bolts for a 5.4 coils it did not have that size.
 
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GoodEnough

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MLB0611 said:
They are set up to start with damaged threads, thin treads to start out.

As for finding the correct size, match the bolt to the thread chaser, or the bolt chaser, either line up a good bolt to the threads on the thread chaser or thread it into the bolt chaser. most times easy to do than explain.

HTH
Click to expand...

That's a good reason to get the Kastar kit with the bolt cleaner to clean bolt threads...Just see which bolt cleaner the good bolt fits, and use the same sized hole cleaner top clean the threads. Right?
 
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OccupantRJ

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GoodEnough said:
One more thing. What if I misthread a bolt hole, and resort to a thread chaster kit.
How will I know which the right one is? If it's like the bolt, won't it also misthread and not go in correctly? Often you do not know the M1x6 size of the bolt you just misthreaded. How will you now you're using the right sized chaser if the threads are all messed up already , and it's not going in right?
Click to expand...

There is a device called a screw pitch gage with teeth on selectable blades to match the available screw (bolt) threads. It is marked, and when placed in the threads of the bolt, will tell you the pitch (spacing) of the threads. Another known bolt of the same pitch can also be used as a gage by meshing the threads of the two bolts.

M8 x 1.25 x 20 would mean that the bolt is metric, shank is 8 mm diameter, the thread peaks are 1.25 millimeters apart, and the bolt length under the head is 20 millimeters.
 
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ajchien

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GoodEnough said:
One more thing. What if I misthread a bolt hole, and resort to a thread chaster kit.
How will I know which the right one is? If it's like the bolt, won't it also misthread and not go in correctly? Often you do not know the M1x6 size of the bolt you just misthreaded. How will you now you're using the right sized chaser if the threads are all messed up already , and it's not going in right?
Click to expand...

If you're doing DIY automotive work, you'll get to know your threads pretty quickly. Google is your friend. If you want more confirmation, you can buy a thread pitch gauge fairly cheaply.
 
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dr_clyde

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The craftsman one you linked is fine for standard (american) threads. Look for one just like that for metric as well. No need to spend Starrett or Mitutoyo money here. You're not a machinist.

The plastic gage listed on amazon is not a pitch gage, despite being labeled as one. What that is is a bolt and nut sizing gage. If you had a random bucket of fasteners, that would allow you to quickly sort them by diameter, but would tell you nothing about the thread pitch.
 
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Murphy4570

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Dude you are asking very basic machinist questions.

Before you spend any money on taps and dies, you should spend money to educate yourself on them. Buy a book or two on basic machining to familiarize yourself. Tools are useless if the person using them isn't trained properly. Self training is more important than the type or brand of tools you buy.

Once you know the difference between SAE, Metric, and Pipe threads, as well as the various ways to repair threads and fabricate hardware, you will be able to effectively use a tap and die set.
 
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dr_clyde

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I was referring to the pitch gage, not the thread restoration kit. The kit you linked would do fine for most general work.
 
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Heavy tech

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Heavy tech said:
This one


Sent from my iPhone using Tapatalk
Click to expand...

You can use this and an open end wrench to tell the size of a bolt pretty easily. A M10 bolt for example, a 9mm open end won't quite slip over the threads, and a 11mm will be loose. A 10mm will fit with almost no play. If there isn't a metric wrench that fist snug try an SAE one.

Just because a car is domestic doesn't mean it's not metric. You will probably metric 85-90% of the time.


Sent from my iPhone using Tapatalk
 
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GoodEnough

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4


If you get the entire kit, and want to clean up a bolt's threads,
do you use the file or those nuts?
 
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GoodEnough

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The Kastar seems to be filled with SAE.
http://www.ebay.com/itm/40-pc-SAE-Metric-Thread-Restorer-Kit-Kastar-972-/230978740106

I might just get the Ebay chasers for $18, and a $15 thread file.
And just not have the "die" nuts. (Is the file good enough?)

I see 2 types of metric thread files.
One starts with .75 as the first size.
The other starts with .80 for the first size.
Which is better for auto?

http://www.ebay.com/itm/Metric-Thre..._Automotive_Tools&hash=item589db52aca&vxp=mtr

http://www.ebay.com/itm/Jawco-8-Nu-...-0-80-3-00-mm-Pitch-Made-in-USA-/181267218244
 
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Mohawk Dave

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I bought that CMan 48 pc set b/c of GJ. I use that set ALL THE TIME!!!! Worth it's weight in gold.

Don't let Murphy scare you off.:lol_hitti
Even though this is basic (for most of us), not everybody has learned it. You came on here and asked, so props! That's how you learn. Now after reading replies, more and more will make sense. The puzzle starts coming together. BTW, I'm not doggin' on you Murphy. :beer:

So, like he said, learn here, learn from books, learn from the internet. Just keep learning until it's no longer fun. :thumbup:
 
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ajchien

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OccupantRJ said:
Use the "nuts" until the bolt you are working on is larger than the largest one, then you file on larger ones, such as something with a 2 inch diameter.
Click to expand...

I also use the hex dies first.

I personally get frustrated with those thread files. I can't seem to get decent results with them. Usually after going over the threads endlessly without any change and some choice words, I bring out a triangular Nicholson file to finish the thread cleanup. Not optimal, but gets me finished. If someone can tell me how to work those thread files better, I'd be grateful!
 
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Mohawk Dave

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ajchien said:
I also use the hex dies first.

I personally get frustrated with those thread files. I can't seem to get decent results with them. Usually after going over the threads endlessly without any change and some choice words, I bring out a triangular Nicholson file to finish the thread cleanup. Not optimal, but gets me finished. If someone can tell me how to work those thread files better, I'd be grateful!
Click to expand...

I'm jonesin for some of these. I got a couple at a yard sale one day and had no idea they existed. I'd like a nice new set. Mine are kinda buggered up. They are 2 piece so you can put it up on a bolt and work your way off it. BRILLIANT!:pimpflash

https://www.google.com/search?q=JME...fXoASJ2YH4DA&ved=0CAkQ_AUoAQ&biw=1360&bih=639
 

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