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john hobdeclipe
01-01-2017, 09:35 PM
So far, all of the single point threading I've done has not required great accuracy...If the nut fits, then it must be OK. But I want to begin doing some work that will demand a bit more accuracy. To that end I have ordered a set of thread wires for measuring male threads and next I need a "Go/No Go" gage to test the corresponding female threads. I'm anxious to get these and start learning to use them.

This is for 1"-8 tpi threads. I need to make some lathe face plates, and eventually I'll be making an entire new spindle for an old Walker Turner wood lathe, plus perhaps another spindles for different machines.

So my question is: When I purchase a Go-NoGo gage, should I get a class 2B or the somewhat more accurate 3B?

It all must work together...the face plates must work on old (40 to 50 years old) Rockwell/Delta wood lathes, and the spindle must work with any face plates and accessories I have/make.

So, which thread gage should I invest in? 2B or 3B?

Thanks.

becksmachine
01-01-2017, 11:18 PM
Since you will have the thread wires, you would have all the capability you need to make your own.

You get to pick your material, I would recommend 12L14 or Stressproof, with a new insert or a meticulously ground HSS version, and proceed down the path of learning the subtleties of single point threading.

This way, you can have both 2B and 3B and any other custom combination of major diameter, pitch diameter and pitch that you need now or in the future.

Dave

dalee100
01-01-2017, 11:40 PM
Hi,

Thread go/no go gages are really great for production. A fast quick way to tell if you made any one piece into junk or not. Not so valuable in the homeshop perhaps. If you want them, make them yourself. 2b gages are good enough for 99% of what ever you do.

Dalee

JoeLee
01-02-2017, 12:15 AM
I don't have any go no go gages or thread wires..... yet, I've always got by with out them because when I cut either an internal or external thread when I get to the point where it almost fits the mating part I'll take light cuts and keep checking until I get the fit I want, some very close tolerance and some with some wiggle room.
This is all OK providing the part is small enough to screw onto the part in the chuck that I'm threading, other wise I have to make a gage which I had to do a few weeks ago when I made the leveling screws for my balancing stand. The hole in the base plate was tapped and the plate was too big to try and screw on to the part in the chuck so I had to make a go no go gage.

JL................

danlb
01-02-2017, 01:52 AM
So far, all of the single point threading I've done has not required great accuracy...If the nut fits, then it must be OK. But I want to begin doing some work that will demand a bit more accuracy. To that end I have ordered a set of thread wires for measuring male threads and next I need a "Go/No Go" gage to test the corresponding female threads. I'm anxious to get these and start learning to use them.

This is for 1"-8 tpi threads. I need to make some lathe face plates, and eventually I'll be making an entire new spindle for an old Walker Turner wood lathe, plus perhaps another spindles for different machines.

So my question is: When I purchase a Go-NoGo gage, should I get a class 2B or the somewhat more accurate 3B?

It all must work together...the face plates must work on old (40 to 50 years old) Rockwell/Delta wood lathes, and the spindle must work with any face plates and accessories I have/make.

So, which thread gage should I invest in? 2B or 3B?

Thanks.

You definitely want a 2B for that application. The reason is that the face plate's threads pull the registration feature (a spigot in your case?) into alignment. If you make the threads too close a fit it can prevent the mating faces of the faceplate and spindle from aligning properly.

To get a feel for how close the tolerance is on your lathe, unscrew your faceplate 1 turn and then wiggle it about. My little Delta midi lathe's faceplate will wiggle quite a bit when unscrewed half a turn.

If you make the thread a very tight fit it might not be as interchangeable on the other old lathes since some may have less wear on the threads and others that have mild distortion/dings. Those will be more likely to bind if you use a very tight tolerance thread.

Source: http://www.engineersedge.com/thread_strength/thread_classes.htm

Dan

mattthemuppet
01-02-2017, 12:28 PM
I made a copy of my spindle nose (a go gauge I guess) when I made a chuck back plate for my lathe. Works well.

DR
01-02-2017, 01:54 PM
This is for a wood lathe. Wood lathe spindles don't have a chuck registration feature like metal lathes sometimes do.

1"-8 thread is common on smaller wood lathes. Most spindle and faceplate combinations have a very loose fit. This is for a good reason, most any parts from a combination of maker's tooling will fit together. Even a loose thread fit on a wood lathe usually is not an issue.

Where a real problem in spindle threads occurs is when you get into the high end wood lathes in the $5K range price range. These lathes typically use a larger thread size like a 1-1/4"-8. The high end lathe makers make their spindles and their own screw on accessories, faceplates/chucks, etc with close fits for repeat ability and a quality feel. The result is, spindles and screw on accessories don't always interchange between brands in these machines even when the nominal thread sizes are the same.

john hobdeclipe
01-03-2017, 02:01 PM
Thanks, guys, for the input.

Danlb: What you are saying makes good sense. Essentially you clarified what I was kinda thinking.

becksmachine & dalee100: What you're saying makes good sense, also. But for the moment, I think I may be better off with a plug gage of known quality. As I gain more and more experience, the time will come when making my own gages should be more practical.

I have a number of small face plates here that are nothing more that a 1"-8 hex nut with a steel disc welded on and then trued. For everyday use they work fine, but I have some projects and ideas that will require a bit more precision, thus my desire to cut both external and internal threads more accurately.