VaughnT

What do we know about Taps and Dies?

Recommended Posts

There was an article in Fine Woodworking magazine that discussed this, back in 1983.

Share this post


Link to post
Share on other sites

I don't think my old issues go back that far, but I'll see what I can find online. It could be an interesting read. Thanks.

Al (Steamboat)

Share this post


Link to post
Share on other sites
2 hours ago, ThomasPowers said:

Do your OHJ go back to the 3 hole punched days?

 I started collecting Old House Journal maybe a year or two before I published an article in one of their 2013 issues. I do have some Fine Homebuilding issues that go back quite a bit further than that.

1 hour ago, duckcreekforge said:

I thought this was taps and dies? Tangent woodworking comment mislead or did the train jump track?

Hmmm. Taps and dies. That sounds familiar. :) Topics do tend to "evolve" around here...happens a lot. I'm perfectly happy going back to the taps and dies "thread" though.

Al (Steamboat)

Share this post


Link to post
Share on other sites
On 11/2/2018 at 5:53 AM, Steamboat said:

The Japanese have a special name for this joint. Check this link: http://www.aisf.or.jp/~jaanus/deta/j/jigokuhozo.htm

very interesting, and reinforces the need for definitions. What pops into my mind for a blind tenon is a situation that the length of parent stock, think picket or stretcher with a tenon integral on each end cannot fit into the space. Thus, the solution is a blind tenon, a stud applied thru the top of the mortise and secured one way or another into a hole in the picket/stretcher. Then the "blind" tenon can be headed over and, in the case of a railing, the rivet head detail is not interrupted.  check out the joinery I used here. The tenons are not peened over. This is a roller for a stand. the roller is 3/4" round sleeved with 1" tubing. There is 1 forged tenon and 1 "blind" tenon on the other side. The roller assembly fits in easily and I do not have to stress the roller frame. because I use a "starting" tap, and a bottoming tap, the threaded stud is screwed in and fully bottoms out. Thus heading the tenons is quick and will last indefinitely, and the sleeve will be free to spin. 

There may be other solutions to this problem, but I've not come across any better to date.

I've considered Thomas's solution of stock removal but in a small hole, a chisel won't work. And to wallow out with a drill bit would wallow out the top which adds far too many other unacceptable problems that must be delt with.

The use of a dremel type tool may work, but certainly would not be quicker than running a tap thru twice. And without a doubt the cost and longevity of two taps and and a tap wrench are far exceed clear of any power tool within my experience. 

However, this thread has brought forth another viable option and that is a split stud and a wedge.

And that's exciting!

For what it's worth, I made a series of shop stands that are all hand forged with the joinery left obvious to show the "story", not to leave one wondering how it was done. Thus my tenons are left proud and my welds are obvious.

2017-08-14 08.58.58_32.JPG

Share this post


Link to post
Share on other sites
18 hours ago, duckcreekforge said:

I thought this was taps and dies? Tangent woodworking comment mislead or did the train jump track?

It is supposed to be about taps and dies -- hence the title of the thread.

The funny part is that a moderator just hit me with a "demerit" for spamming, yet here are all these people spamming away, cluttering up a thread with nonsensical comments that have absolutely nothing to do with the subject matter being discussed.  This is the kind of stuff that makes the search function here even less functional.  

Since you all want to talk about woodworking on an ironworking forum, let's at least try to keep it within the of the subject being discussed in the thread.

Here's a very nice video on making wooden threads -- with information I'd never heard before.  Love the bubbles!

https://www.youtube.com/watch?v=nbY6El9Pzcs

 

If you want to talk about tenons in wood furniture, please feel free to do so in another thread.  If you're curious about how far back in time someone's magazine collection goes... again, feel free to start a line of discussion around magazine subscriptions.

Share this post


Link to post
Share on other sites

Sorry, Vaughn. I have a 'tenon-cy' to get carried away sometimes. Getting back to the "threading thread," I have a few suggestions that I find useful:

First of all, I use thread cutting oil, which helps cut cleaner threads and makes the dies and taps last longer. It seems to help reduce the effort as well. I really can't say which cutting oil is "best," because I really don't know. I've used several different brands successfully. Just make sure that the cutting oil is recommended for your application and follow the instructions and safety guidelines.

While I'm threading a rod, about once every three or four new threads, I unscrew the die, brush off the swarf with an old toothbrush, and then screw the die back on and continue to cut more threads, repeating this until I'm finished. A little patience usually pays off. Preventing the swarf from building up will help make cleaner cuts and help prevent flakes from getting wedged between the die and the threads. I use a similar approach when using a tap to thread a hole. If it's a blind (closed) hole, you'll have to figure out how to get the swarf out after the tapping is done. I usually use a liquid aerosol cleaner with a long, thin plastic tube attachment. Be sure to follow the instructions and safety warnings when using aerosol cleaners and solvents. If you leave cutting oil in the hole it can affect torque readings,  threadlocker effectiveness, etc.

I'd like to echo Kozzy's comment about buying quality taps and dies. I don't have a specific brand to recommend, but at the minimum, get "high-speed steel" rather than "carbon steel." They're pricier, but in the long term they're more economical because when used properly, they should far outlast the cheaper ones. If you want even greater longevity and better threading characteristics, you could buy high-speed steel taps and dies with titanium nitride coating, which is especially recommended if you're threading stainless steel, which can be challenging to thread. Make sure that your cutting oil is recommended for stainless steel, and go slowly when threading stainless. It's still no cakewalk to thread stainless, but that should help. There are a lot of other coatings available, but titanium nitride is the most common.

If you want to thread a rod that has mill scale or forge scale on it, remove the scale right down to clean metal before threading. Your dies will last a lot longer and you'll get cleaner threads.

There are high-performance tap and die materials available, such as cobalt steel for threading hardened steel, and special taps and dies for threading titanium, etc., but for most purposes high-speed steel (preferably with a titanium nitride coating or similar) will work great and last a long time when treated nicely. Taps and dies for use with mills and lathes and other machinery bring up a whole new list of possible options too lengthy to mention here.

Also remember that there are different "chamfers" of taps, which refers to the number of tapered (or incomplete) threads at the starting end of the tap. The most typical are "taper" (or "starting"), "plug," and "bottoming," but there are other names and variations on these. The taper tap makes it easier to start tapping a hole and helps you align the tap within the hole. The plug tap is good for most general-purpose tapping, and the bottoming tap has full-diameter cutting threads just about all the way to the starting end or "front" of the tap, which lets you cut threads almost all the way to the bottom of a closed or "blind" hole. I think that a bottoming tap should only be used when necessary, since in my experience I think it produces a slightly rougher thread finish and requires more torque than the other chamfers. When I need to use a bottoming tap, I first tap the hole as far as I can with a plug tap and then just use the bottoming tap for cutting the last few threads at the bottom of the hole.

Getting your taps and dies started in correct alignment is perhaps the most challenging thing about threading. Some die handles (aka, wrenches) have built-in adjustable centering guides to help start the die straight. To make a simple jig for starting taps in holes, use your drill press to drill a nice straight hole through a 1"-thick piece of hardwood and clamp the wood flat on the surface of the object to be tapped, with the hole in the wood directly over the hole that you want to tap. The hole in the wood serves as a guide to start the tap straight. This general idea can sometimes be used in conjunction with a threading die as well. There are a LOT of other ways to get the tap or die started in proper alignment, but I'll leave those to your imagination.

I also recommend buying adjustable dies that allow you to make minor adjustments to the thread diameter to produce the kind of fit that you want in the female threads of a nut or threaded hole.

I could also mention that there are special taps and dies for reconditioning threads that are a bit rusty or slightly damaged. You may hear terms like chasing, repairing, rethreading, restoring, etc. and there are a lot of variants among these dies, which I won't go into here. Just remember that these can't perform miracles. If the threads are too damaged, replacement may be the best or safest option. Also, be SURE to clean debris out of the threads before using a thread reconditioning tap or die.

I'm sure I've forgotten to mention a few things, but that might give you a couple of useful ideas, and I hope that we're back on topic now.

Al (Steamboat)

Share this post


Link to post
Share on other sites
On 10/27/2018 at 10:18 AM, VaughnT said:

Were tapered taps commonly used back in the day?  How rare were drills that punching the hole was the best option... yet they could make such nice tapered taps?

Or were the tapered taps used for something else entirely?

From the photo you included of the tapered taps, it appears that they are tapered continuously along the full length of the cutting threads. You might have a closer look to see if there might be a very short section at the large end of the threads where there is no taper. However, at this point I am assuming that they are tapered all the way, and if so, there are a number of possibilities as to their type and purpose, but I cannot give you a definitive answer.

I did find some information in Handbook of Small Tools, by Eric Oberg, 1908, which you might find useful. There is a 40-page chapter on "taper taps," which describes a number of tapered taps, such as:

  • "Pipe Taps"
  • "Taper Boiler Taps"
  • "Patch Bolt Taps"
  • "Mud and Wash Out Taps"
  • "Blacksmith's Taper taps"
  • (A few other types of tapered taps are described as well.)

It's possible that your taps don't specifically fit any of these categories, but it's a start. Here's the link:

https://books.google.com/books?id=nplKAAAAMAAJ&pg=PA257&lpg=PA257&dq=blacksmith+tapered+taps&source=bl&ots=S6IaJIlAwp&sig=yZ8Ho9E8xddezQvYpdTNP-Mszmc&hl=en&sa=X&ved=2ahUKEwjese-XtbzeAhWig-AKHchOAQQQ6AEwAXoECAgQAQ#v=onepage&q=taper taps in general&f=false

Al (Steamboat)

Share this post


Link to post
Share on other sites
On ‎10‎/‎30‎/‎2018 at 3:04 AM, anvil said:

The other is bottoming taps. The "usual" kind you buy are starting taps and the working end is tapered.  They do not cut threads all the way to the bottom of a blind hole. Bottoming taps are flat cut and will cut threads to the bottom. 

we call these plug taps and starter taps, we also have intermediate taps, plugs are for finishing a thread, starter taps are for starting, and intermediate taps are for rough cutting where it will be temporary. I absolutely hate taps and dies because I always learnt with plug taps and cheap dies that would not cut for the life of them.

Share this post


Link to post
Share on other sites

Al, good info!  No harm meant with my earlier comments.  I appreciate the solid knowledge you're sharing, wood or metal! ;)

 

Got three complete tap sets in the mail the other day.  Minty fresh, never used Taper, Plug and Bottom for all three!  I'm still hunting for an old-school set of the 1/2-12BSW, but there's no hurry.  The hunt is half the fun -- even if it's for something I'll probably never use!

IMG_7030.thumb.JPG.29b3c5f1047a2ff9145548e7a279ecc3.JPGIMG_7032.thumb.JPG.d46026ed334e325e56c71fc39bf46e66.JPG

 

Already got a small project in mind that'll require my 3/8-16 tap and die.  Not sure it'll work, but I'm sure it'll be fun to try.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now