Single Point Threading = no Depth Gauge Joe P.

[Janderso]

Most all modern thread mics now have interchangeable anvils. Gone are the days of the beautiful Starrett and Lufkin fixed standard thread mics. My Tesa set, Mitutoyo, B&S and even the cheap Chinese ones all have interchangeable anvils. Aesthetically, I don't think the more modern tools are better but changing anvils is a lot cheaper than having separate mics.

I toyed with the idea of buying a quality used thread mic on E-bay, when I saw the small range of threads they measure I decided I don’t need a set that bad.
I like the idea of buying one with interchangeable tips.

 

[mikey]

I toyed with the idea of buying a quality used thread mic on E-bay, when I saw the small range of threads they measure I decided I don’t need a set that bad.
I like the idea of buying one with interchangeable tips.

Shars sells a set for under a hundred bucks for a 0-1 thread mic. Reads in tenths, too. Most higher end mics will read in thousandths, although you can interpolate easily enough for greater accuracy, as John said.

 

[ttabbal]

I have the Shars 0-1 thread mic. I think it works quite well. Like all precision tools it takes some practice to get good repeatable measurements. I grabbed some known good fasteners from McMaster and fastenal and measured them, comparing to a chart to make sure I'm in the right range. Once I got comfortable, I used it for cutting and got a great fit.

I tried with home store bolts, but I got weird results. Turns out I was doing it right and they are barely in spec and some were slightly out. Explained why some of them didn't fit the nuts well. It was confusing at first though.

 

[Alexander McGilton]

I wish some one would tell this to Heidenhain. This is a clipping from the heidenhain 4110 manual. It request that you specify the thread depth by radius dimension U of major diameter to root. I would wish that they made the system work by thread pitch diameter and the theoretical convergence of the tool. Though that would make things more complicated for the user. What I do is set the U to 0.5*F1, take a test cut then compensate linearly after checking with the thread micrometer.

 

[Janderso]

For nearly all my threading, I use the threading tools from Aloris, they are made in several sizes according to the width of flat at the point of the tool, they are sharpened only on the top, and last a very long time. Yes, thread wires are a PITA, and I seldom use them, and then, only if my thread mikes are too small, then I go to my old shop and borrow the larger one. I think one can read a .001 thread mike to within a few tenths by approximation, I have never had to make anything closer than that. At my old shop I had a collection of thread ring gages, and used them to fit most threads.

You talking about this style John?

 

[Janderso]

More threading fun today.
I’m gaining confidence. This is a 5/16 18 thread. No I didn’t use a die, what’s the fun in that

 

[MrWhoopee]

More threading fun today.
I’m gaining confidence. This is a 5/16 18 thread. No I didn’t use a die, what’s the fun in that

As Fred would say:
"You do nice work........
damn little of it, but nice work"


But seriously, nice looking part. You're definitely getting the hang of this.

 

[projectnut]

You talking about this style John?View attachment 319666View attachment 319667

I have a couple threading tools like that. One is for the BXA tool holder and the other is for the AXA tool holder. They're nice if I have to do long threading or multiple pieces. However I find myself using a plain old HSS tool ground to a 60* angle more often than not.

Like benmychree I've made several plug gauges for testing internal threads. The first one I made was for a 1 7/16-12 backing plate on my Seneca Falls Star lathe. It turned out perfect and I was extremely proud of it until I tried to use it. No matter what I did I couldn't get it to fit my practice piece. I was frustrated beyond belief and finally put a thread gauge on it. In error I had put the wrong change gear on the lathe. Instead of cutting a 1 7/16-12 thread I was cutting a 1 7/16-11 1/2 thread. Since I've never owned or worked on anything with a 1 7/16-11 1/2 thread I've never had the occasion to use the plug. I do however keep in a prominent place where I can see it while using that lathe. It's a constant reminder to check twice and only have to cut once.

 

[Bamban]

Projectnut,

Are you telling me a 1-1/16x16 barrel tenon will not screw all the way into an action with 1-1/16x18 thread?

Well, I tried desperately, and in fact I cut off the tenon and cut new one, still the same results.

My brother has a glued in bench gun, I volunteered to make him a fire forming barrel from a shot out barrel. The action being glued, can't test fit till done since I was chambering through the headstock.

I downloaded the tenon print from the action manufacturer, used it to cut the barrel, somehow I proved I could not read, my mind was focused on the 1 1/16, and at that time I was doing a lot of AR15 barrels with 16 TPI tenon. Automatically, I set the gearbox to cut 16.

Not till I failed on the 2nd attempt did I read the print again, and there it was - 18 TPI.

 

[Janderso]

Bamban,
I had to read your post twice to find the error. Oops.
Hey, you knew enough to figure it out.