So how can I verify my own work? Trued a 700

[Alex Wheeler]

Make your jig with the 2 setes of jacking screws about 1.5" inches apart. Hold the action by the front ring only and let the tang float. You have found why. Actions are extremely easy to bend in a fixture.

 

[Shawnba67]

I would like to publicly thank Dave Tooley who extended his knowledge and help to me a extremely green fellow with not enough experience to know how lost i am. He gave me some really great advice and direction, and i had enough forsight that i took notes!
I would also Like to THANK EVERYONE who has helped me(or anyone) on this forum,
I am still amazed at the friendliness and help I have recieved from you guys even when the questions are dumb!
THANK YOU
I am also very glad to see others just getting started receiving help and giving what help they can.
I will post back once I've inflicted Daves advice

 

[Shawnba67]

Make your jig with the 2 setes of jacking screws about 1.5" inches apart. Hold the action by the front ring only and let the tang float. You have found why. Actions are extremely easy to bend in a fixture.

I bought the Tannel dvd and he stated it only took 40inlbs to bend one, I put a stubby wrench onto a inlb torque wrench and found I was able to make 40 inlb using only my thumb and 2 fingers around the box end if i used any wrist at all it was very easy to overtake the 40inlb I like Alex's idea much better than the way i did it I was just passing on how small a torque were trying to deal with

 

[paperpuncher]

http://www.bryantcustom.com/articles/true.htm
I use a jig like the one picture in the link. Much easier to steer the action without bending/binding.

 

[jkohler]

Mine is just as mike Bryant's as well.

 

[PWS]

Duh! Never thought of shorter screw spacing... Great suggestion.

Got out to shoot on Friday and the only conclusion so far is no harm done. Weather was pretty raw with a high pressure front moving through with snow, low teens and maybe +/-20mph gusts from all directions. Seven five shot groups averaged 1.57moa at 100yds so need much better test conditions.

 

[PWS]

Spent all day yesterday and this morning and played with testing thread fit and alignment.

First thing I did was turn a test "receiver" out of a 12" section of 1 1/2 schd80 pipe. Held one end of the pipe in the three jaw, used a HDPE plug to hold the tailstock end and trued the OD there for the stead rest. Moved the tailstock out of the way, set up the steady and bored and threaded the open end to emulate receiver threads. Also cleaned up a section of the OD 10" back toward the chuck. Figured this would give me a set of threads coaxial to a point of reference ten inches away. Then, turned and threaded a test tenon to fit the pipe ID and left it in the chuck.

First test was with the threads as tight as I was barely able to thread fully on by hand. Test "receiver" coned approximately .010" per revolution. The cone moved upward a total of approximately .030" as more threads engaged (makes sense - the receiver was drooping less as it threaded on more). It showed .005" runout at 10" when butted to shoulder. Length of engagement was approximately .600" (nine threads) so the .010" cone calculates to .0003" misalignment over the .600" length (x/.6=.005/10).

I then made five tests at -.0005" a side and the only thing that changed was the amount of initial droop. Makes sense that as the threads opened up, it allowed for more initial sag. It was interesting to see the size of the cone remain the same. Perhaps it just shows that threads that are aligned are aligned whether tight or loose. I was not able to improve on the .005 butted runout and, in fact, it got worse skipping up to .010" then .015" for the last three tests. Tried retruing the tenon shoulder but it didn't help and fear the "receiver" face was out of alignment.

So the $64,000 question is what fit should be targeted for the barrel/receiver joint?

Bill Hambly-Clark says that "The thread fit I aim for, is to be able to screw the receiver all of the way against the shoulder EASILY (his italics), back it out about .005", and have no movement when I try to move the receiver up and down at the rear tang".

I would assume this also includes both threads are as close to concentric as possible and receiver face and barrel tenon are as perpendicular as possible to that axis.

Any thoughts?

 

[boltman223]

I would assume this also includes both threads are as close to concentric as possible and receiver face and barrel tenon are as perpendicular as possible to that axis.

Any thoughts?

With a 3 jaw and a steady rest concentrisity and perpindicularity doesn't happen by chance (in fact it never does realy) and assuming it is, is the first mistake. Issues are only multiplied 12 inches from the chuck.

 

[boltman223]

Did you measure for taper after turning and boring while in the steady rest? And for what youre doing you should using a four jaw.

 

[DaveTooley]

Shoulders perpendicular to the bore should be the easiest, most predictable result in the accruizing process. A simple, reasonably close fitting mandrel is all that's required.

If you agree with that statement then remove the possible influence of the threads by having a loose fit. Loose threads,loose 3A to tight 2A fit ( they do overlap), means square shoulders. I do a lot of work on both bolt and gassers, where barrel extensions are used. Sometimes because of the length of the tenon and the quality of the extension a middle of the road 2A fit works better.

There is nothing and I mean nothing to be gained by close fitting threads.

 

[boltman223]

Spent all day yesterday and this morning and played with testing thread fit and alignment.

First thing I did was turn a test "receiver" out of a 12" section of 1 1/2 schd80 pipe. Held one end of the pipe in the three jaw, used a HDPE plug to hold the tailstock end and trued the OD there for the stead rest. Moved the tailstock out of the way, set up the steady and bored and threaded the open end

I wouldn't remove the tailstock before setting up the steady rest.

By any chance did you check (the tailstock end) for runout before and after using the tailstock?

Was the schedule 80 pipe round and straight to begin with? Using all of the jaw (the whole length of it)If the pipe is not straight enough and/or your chuck causes too much runout will create more issues turning between centers or using a steady rest.

I'm not sure what a HDPE plug is either. I'm guessing it already had a hole for your center in it.

 

[PWS]

Here's a pic of the setup to turn the test "receiver". To stay on topic, the reason for the exercise was in consideration of "how to verify my own work". To do so, it seemed prudent to start with a test "receiver" that is known to have threads coaxial to the point of indication.

Note: In the picture, there is very little pipe within the chuck jaws only because I cut it off later for easier handling. The original setup had approximately 4" more pipe within the jaws and further into the spindle bore.

After chucking the pipe into the 3-jaw and using a center drilled plastic plug to provide a temporary center for the tailstock, I cut a race for the steady and a race just in front of the 3-jaw for indication. By doing this in one setup, I felt that it would provide two accurate points along a single axis regardless of the straightness or roundness of the pipe.

In retrospect, I should have installed the steady before moving the tailstock but my lathe has an 18" bed so things get cramped rather quickly. Also, I falsely assumed using the steady would ensure a perpendicular shoulder, however, since the shoulder formed at the end of the pipe is a ring only .060" wide, it should lie on a plane perpendicular to the axis of the two trued surfaces. I also did not check for taper after boring and threading and this certainly could have had an effect on my results.

Despite the shortcomings of the test receiver, I do think it's threads hold close enough to the axis of the test race to suggest exactly what Dave Tooley states, that "There is nothing and I mean nothing to be gained by close fitting threads". Even after increasing the slop of the test tenon by .006" diameter, runout while installing the test receiver remained .010". Initial alignment between the two parts increased but final alignment at the point of shoulder contact did not.

So during execution and verification of my own work,

1. Ensure tenon shoulder and receiver face are perpendicular to their respective axis - while most important, it's also easy to achieve and to test.

2. Threads are as parallel and as coaxial as possible - more difficult to achieve and test but it appears that a runout of .010" or less during assembly is attainable and...

3. Thread fit, to paraphrase Mr. Tooley, is "loose enough to allow the square shoulders to mate".

Thanks everyone for the information and suggestions. I apologize for being long winded but it takes a while for info to sink in and the thought and effort it takes to type it up helps.


Looking forward to reading about Shawnba67's results!

 

[boltman223]

Is that an adjust true 3 jaw chuck?

 

[GenePoole]

If that's a stock South Bend chuck, then no, it is not. Even if it's not, I don't see any adjustment screws.

 

[boltman223]

If that's a stock South Bend chuck, then no, it is not. Even if it's not, I don't see any adjustment screws.

I didn't see any either. He mentioned indicating and I was wondering exactly what he was indicating then.

 

[butchlambert]

I didn't see any either. He mentioned indicating and I was wondering exactly what he was indicating then.

You may not figured out what he is doing yet. It doesn't matter what chuck that he is using. He is indicating and machining from the steady to the right. If he takes an OD cut and bores the ID, they will be coaxial to each other and the shoulder will be perpendicular to the OD. I'm sure he would have used another method to indicate the metal in the chuck if it were going to be used. I interpreted his post to mean he was checking his work which is to the right of the steady.

 

[boltman223]

You may not figured out what he is doing yet. It doesn't matter what chuck that he is using. He is indicating and machining from the steady to the right. If he takes an OD cut and bores the ID, they will be coaxial to each other and the shoulder will be perpendicular to the OD. I'm sure he would have used another method to indicate the metal in the chuck if it were going to be used. I interpreted his post to mean he was checking his work which is to the right of the steady.

That's why I asked actually, too make sure. You can't indicate to the right of a steady. Check to see if it is parallel to the ways, yes. The material to the right of the steady will turn true to the steady even if not centered correctly in the steady.

If I understood his process correctly and by looking at his pictures everything wasn't done in the same setup.


I'm not disagreeing that the ID and OD wouldn't be concentric. But, It appears all cuts weren't done in the same setup. There's just a few variables that could/would skew his results once removed checked.

 

[butchlambert]

That's why I asked actually, too make sure. You can't indicate to the right of a steady. Check to see if it is parallel to the ways, yes. The material to the right of the steady will turn true to the steady even if not centered correctly in the steady.

If I understood his process correctly and by looking at his pictures everything wasn't done in the same setup.


I'm not disagreeing that the ID and OD wouldn't be concentric. But, It appears all cuts weren't done in the same setup. There's just a few variables that could/would skew his results once removed checked.

My thought was he was indicating and measuring his work to the right of the steady. Yes, it will be true to the steady. I don't think he could take the part out and easily reindacate it back in easily..

 

[PWS]

You all probably gather that I'm just a hobbyist and I do appreciate the further input and critique. The 3-jaw is non-adjustable and I guess that it took two (maybe 1 1/2?) setups to make the test "receiver". Here are the steps:


1. Turned temporary center plug and installed in pipe.
2. Chucked other end of pipe in N/A 3-jaw, let it run where it was pointed (thanks to YouTube "Tom's Techniques"), and cut center in plug.
3. Swapped center drill/chuck for live center in end of pipe.
3. Made a cleanup cut on the OD of the pipe just in front of the 3-jaw (10" from tailstock end) and another cleanup cut 3 1/2" from tailstock end. Second cut was to make a race for the steady rest.

Here's where I made a mistake.

4. Removed tailstock and then installed steady on race.

Now that I know, I should have tried to leave the tailstock in place before installing the steady. Not sure exactly why I did this but it may be because there wasn't enough space for to leave the carriage between the tailstock and the location of the steady. I do recall taking the tailstock completely off the lathe bed. FWIW, the pipe is stiff and the 3-jaw has a good bite so it "shouldn't" have moved too far off center if it did.

5. With pipe in 3-jaw and steady running on truing cut, removed plug and faced, bored and threaded open end of pipe.
6. Hacksaw extra pipe beyond first truing cut for convenient handling.

Done.

The pipe never left the 3-jaw until all machining was completed so that end of the setup remained fixed.


Given that the facing cut is a narrow ring and lies 100% on a plane perpendicular to the axis of rotation, it should properly serve its purpose.

However, if the pipe did move off center, the threads could have and most likely did have some degree of taper. Even with this error, they should be on axis and I think the test "receiver" served it purpose in exploring alignment.

 

[boltman223]

there is some potential problems to take into consideration when removing the pipe from the chuck after drilling the center and then puting it between centers. (one of them) If you want to see what I mean, take the pipe, chuck it up on the unturned part and see how much runout you have at the end, whatever it is, one foot, 15 inches or so from the chuck.


This runout is one of the things that can cause problems. When you put it between centers and a good portion of the pipe is chucked up. the pipe will Bend. And, mess up your day. If you chuck up say 3/8 inch it will mitigate this. Just something to keep in mind.