Day 1 Practice - lessons learned. 12/30 update

[mram10]

I woke up bright and early and decided to thread and cut the bolt nose on some blanks. First two turned out much better than expected. The third I took some measurements. I trued the face then cut the shank 1.000 long and turned it to 1.062. Then cut a small relief cut .295 from the shoulder. Seemed to be going well. I threw on my threading tool at 90 rpm after using my fishtail and did a handful of passes, .005 at a time till the outside threads looked sharp. Turned up the speed and lightly sanded. I measured and they had shrunk to 1.057. Then went on to cut the bolt face. Used a 11/16 cutter just to see how it would do, then finished with a short boring bar. My goal was .150 deep and .705 wide. It ended up .143 deep and .702 wide. I didn’t clean off the face good enough when I measuring the depth and must have got a chip on the mouth cause I was sure it was right at .150 in the shop before I cleaned it up.
Lessons learned:
The compound moves when I’m turning the shank down if it is at 29deg.
The chuck t handle at 505rpm goes across the shop
The bolt nose cutter needs a pilot
I should true the shoulder on the shank then clean off the barrel face. I didn’t true the shoulder.

Any advice welcome guys!!
Mike

 

[carlsbad]

You need to focus on only 1 lesson today: Always, ALWAYS, take the tee handle out of the chuck before taking your hand off of it. If you leave it in the chuck for 1 second without your hand on it, you have violated the first rule of lathe safety. This is extremely important.

After you master that one, you can work on machining. Sorry if this sounds harsh but safety has to come first.

--Jerry

 

[mram10]

Not harsh. Prefer to keep my body in one piece. Don’t care about breaking some tools and ruining some steel. Like to keep my teeth intact

 

[Stan Taylor]

Not harsh. Prefer to keep my body in one piece. Don’t care about breaking some tools and ruining some steel. Like to keep my teeth intact

I just finished setting up my new lathe an cut my first set of threads for a stolle panda an chambered a 6mmbr Ackley improved turned out Pretty good.PS patients is a virtrue practice makes it worth ever minute you spend on that machine.

 

[GenePoole]

It looks like you may have missed your mark on the first pass. It looks like there's a groove right on your crest. Also, you should chamfer the edge before you start cutting threads. A 45° edge at least as deep as your thread minor diameter ensures that the threading tool will always contact at the tip of the tool and not the side when it runs up to the workpiece.

 

[mram10]

Making a better post for my bxa qctp and screwed up the thread pitch. Frick! I haven’t got my thread gauges in the mail yet. I need to be more patient

 

[mram10]

Gene, thanks! That is the advice I am looking for. I don’t even know the basics yet. I’ll go try another one with the chamfer

 

[boltman223]

Could be the pic, but it also looks like you tool wasn't perpendicular to the work piece.

 

[mram10]

Hoz, didn’t know that. Thanks! I’ll go read it now

Bolt, which part. Threading, shank turn or bolt nose?

 

[boltman223]

Hoz, didn’t know that. Thanks! I’ll go read it know

Bolt, which part. Threading, shank turn or bolt nose?

Oh, sorry, threads.

 

[boltman223]

Here's something you might like.

http://www.arwarnerco.com/p-22-kit-18-12-inch-threader-nv.aspx

 

[boltman223]

View attachment 1029748 View attachment 1029747
Lessons learned:
The chuck t handle at 505rpm goes across the shop

Haha Can you get a video of that next time?

Why is your compound moving? Maybe that explains why it looks like your tool wasn't perpendicular. That could be why your root looks a little wide too. Keep learning.

 

[mram10]

Bolt,
I don’t know why it creeps a little at times. Mainly if boring bar catches. I noticed it back off a bit. I tightened the drag screw on the compound and didn’t notice it much after. Also tightened the cross slide a bit. I’m going to try threading without the compound. See if that works. My buddy has always done it that way.

Thank God I wasn’t between the wall and that projectile (t-handle)

 

[Danny1788]

Bolt,
I don’t know why it creeps a little at times. Mainly if boring bar catches. I noticed it back off a bit. I tightened the drag screw on the compound and didn’t notice it much after. Also tightened the cross slide a bit. I’m going to try threading without the compound. See if that works. My buddy has always done it that way.

Thank God I wasn’t between the wall and that projectile (t-handle)

Take a picture of how your setting up your compound angle before threading,,, my lathe has to be set at 60.5 degrees, just because the dial on the compound says 30 degrees that doesn't mean it actually is. I looked up your lathe and the compound is setup like mine, at zero mark with a sharpie the 30degree mark on the right hand side then rotate that mark to the 30degree mark on the left hand side of the angle dial. This should get you close but I used a protractor to set mine up then scribed a line on my dial with carbide scribe so I can return to it every time.

everyone has to start somewhere, I'm self taught as well and I've learned a whole bunch from practice and reading books and watching machining videos. Then I started the rifle stuff after I built a few things and was very confident in my threading skills. Keep posting pictures and asking questions you will get it.

 

[Danny1788]

 

[mram10]

Thanks Danny. I have it set just barely past the 60 like your pic. I’ve left it there for almost everything. I’m guessing it should only be there for threading

 

[TRA]

View attachment 1029808

That illustration may confuse someone trying to teach themselves to cut threads. The tool is not shown as it should be.

Ned Seith should edit that to show the proper relationship of the tool to the work.

You definitely need to invest in some pre-ground tooling. Do yourself a favor and purchase some decent tooling You will see a dramatic improvement as soon as you do. Grinding, threading tooling, takes a skill that most don't acquire well enough for cutting such small treads. The thread relief should be cut with a grooving tool.
like shown below. BTW, That's from a Bat print.


Your chuck key incident is no laughing matter. Lathes are very dangerous machines. Many have killed or lost limbs running machinery they were not qualified to be.

 

[Shawnba67]

Can you take a pic of your compound set up for threading?
I ask because once I accidently set my compound at 60 not 29.5 (my dail said 30 but it was 60) and the threads came out very odd looking and lost alot from the major diameter also.
Also my dad knows a guy that had a chuck key ran into his chest and pinned him there couldnt reach the off switch.

 

[mram10]

Fixed the creep issue. Tightened the set screw and this one worked out much better. Good tools are on the way. I bought iscar threading and cutting tools, both left and right. All this has been done with the Chinese ebay stuff. I learned on a harbor freight 110 90amp wire welder with flux. When I got my Hobart 220 mvp, life was easy. Expect the same here. Or at least much easier. Thanks for the tips

 

[mram10]

Day 2-
Cut shank to 1.062 by 1.1. Then trued the shoulder and faced shank cutting length to .958(wanted.950). Cut relief to .284(wanted .280) from shoulder. Using a .3 recoil lug. Cutting tool and steel didn’t get along well, so when I cleaned up the cuts with a file and sand paper, the shank shrank to 1.047 after threading. Mistake. Used the 45 on face prior to threading and it seemed to work better. I also didn’t have an action handy to test the threads, so they are cut way to shallow....I think. Half way through threading I ran in the cross slide .004 then countinued again with compound. Bolt face recess turned out better but I cut it too wide to .729(wanted .705). Tried with boring bar and didn’t watch the crossslide setting close enough. I thought I’d hear it cutting. No luck. Depth was .148(wanted .150) I was happy with that for now.