Day 1 Practice - lessons learned. 12/30 update

[spitfire_er]

Not sure if it has been brought up yet, but you are advancing the cutter into the work with the compound and not the cross feed correct? Feeding with the cross slide and HSS doesn't work or to well normally.

Getting there, but something isn't right. Go back to the basics and double check every aspect, including taking out backlash, using the same # on the dial ( even though it shouldn't matter in your case), maybe use a little lube, advancing the compound 5 thou on the first few passes, then 3 thou. Do a spring pass half way through and before your final pass. Make sure your work isn't out past the chuck further than needed.

 

[GenePoole]

Gene,
What grinding setup would you recommend for a beginner? --Jerry

Good question. I had an import bench grinder with a pedestal that I used for general purpose grinding before I ever got into machining. I still use it. I replaced the bearing with some good ones and it runs pretty good and true. I was going to get a green wheel for it for HSS and carbide, but came across a diamond wheel at a used equipment shop for $20 and adapted it to fit the bench grinder (made an insert to fit the 1" hole to a 1/2" shaft). I rough grind with aluminum oxide or whatever the common hardware store wheels are and do my fine work with the diamond wheel. I see that Shars has similar wheels for not too much ($56). I don't know the quality, but Shars generally has OK stuff for the price. Looks like it'll need an adapter too:

http://www.shars.com/6x3-8-d1a1-diamond-wheel

 

[GenePoole]

Even if the thread pitch can be cut on any number, I just always use the same number and wait for it to come back around. This is how I do it so I know I'm catching the barrel at the same exact point in reference to the lead screw every time. Also after seeing your other posts your last threads are looking better. But just wait for the correct threading tools to come in, I only use ARW HSS tooling and solid carbide micro100 boring bars

I disagree with this. You are not getting the exact same point in the geartrain geometry just because the number is the same. Think about it. You could engage the same number a foot further down the leadscrew. What is still the same in the geartrain? Nothing.

Unless you are doing it the "metric" way and never disengaging the half-nuts, your odds of hitting the same geometry by using the same number are pretty small.

 

[carlsbad]

Hard to face off that t-nut in a lathe without a toolpost.

I'm sure the lathe came with the standard "4 way toolpost". Not as nice as a Quick Change but quite usable. --Jerry

 

[ridgeway]

Beg, plea do whatever to find a machinist that is manual proficient. Pay somebody...take a night class to get the basics. You seem to be determined...just need knowlegable person beside you and it will eventually all click...

 

[Rich S]

View attachment 1029748 View attachment 1029747 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!!

I agree with others regarding getting some help. Ive worked with machinist for years but recently started my own work. I took a class at a JR college that was very helpful. The class moved somewhat slow as it was geared toward folks with no knowledge but none the less worth it.

Regarding your compound moving: All manual lathes have some backlash. Some more than others. Make sure you are always feeding into the work to eliminate backlash on your adjustments. If your taking mic readings and they are not matching your adjustments, good chance its attributed to backlash. There should be nothing wrong with leaving the compound at 29 deg while turning as long as the tool post is properly adjusted.

Verify settings on the lathe with indicators: Id recommend mounting dial indicators to verify your feeds are moving the correct amount and returning to zero. You can also verify the backlash this way. I used a lathe that when you snapped the xslide when threading to a shoulder, the dial moved 1-3 thousands from the original zero. It worked fine for normal turning when there was not that quick snap. This was determined and corrected by verifying what was going on with an indicator. Since you have a new lathe its worth verifying everything is working as it should.

Regarding pilot to cut recess: You should not need a piloted reamer. The pilot would mainly be used to ensure it is centered with the bore. I typically use an undersized reamer held in the tail stock to rough it out. I machine the final dimensions with a boring bar - both depth and diameter. The micro 100 is an economical tool for this. It can also be used to prebore the chamber if you go that direction and to cut the crown.

 

[ridgeway]

There is a lot more going on here other than a possible tool post moving...he needs a mentor beside him, lol

 

[Dusty Stevens]

Another thing i forgot to add that may be elementary to you but im gonna put it in here. The backlash on the compound and cross slide cant be stopped but has to be dealt with. When you run in to set your zero always back up a few rounds and go into it. If you have to back up then back up 4-5 turns then advance back in. Always set up doing this. Like if youre zeroing your tools always back it out then go in never backing back up. Like say you get to the end of your thread and disengage, i back out exactly 2 rounds then advance back to my zero. If you just back out half a round then try to go back to zero you havent got the backlash out. Also another thing i do is when i go back to the right past the tenon and get my tool back on zero i like to go at least an inch or more past the tenon so when i engage the half nut i have time to think plus it takes the backlash out again. What i mean is its threading thin air for an inch or so before it touches the barrel.

 

[Stan Taylor]

Another thing i forgot to add that may be elementary to you but im gonna put it in here. The backlash on the compound and cross slide cant be stopped but has to be dealt with. When you run in to set your zero always back up a few rounds and go into it. If you have to back up then back up 4-5 turns then advance back in. Always set up doing this. Like if youre zeroing your tools always back it out then go in never backing back up. Like say you get to the end of your thread and disengage, i back out exactly 2 rounds then advance back to my zero. If you just back out half a round then try to go back to zero you havent got the backlash out. Also another thing i do is when i go back to the right past the tenon and get my tool back on zero i like to go at least an inch or more past the tenon so when i engage the half nut i have time to think plus it takes the backlash out again. What i mean is its threading thin air for an inch or so before it touches the barrel.

That's very good train of thought Dusty

 

[Roeder]

View attachment 1029808

A picture is worth a thousand words. For those that have never used a Chinese made lathe this explains it. Thanks for posting Danny.

 

[mram10]

Lot of writing in this thread, but I mentioned earlier that fixing the qctp is priority one. For those that say it’s a “slow motion train wreck” save your breath. I’ve done much harder things in life. For those that are helping, I can’t say thanks enough.
Here is the last thread job. Reground tools, sharpened and fixed the qctp so it doesn’t move. Not perfect but improving. Did a pass, blew off with air, oiled, did another pass. Used 2thou on the crossfeed twice to clean it up. Critiques please.

 

[carlsbad]

OK. You've fixed the BIG problem you had. I assume it was the QCTP mount as shortgrass diagnosed. Congratulations. Now you have a quite usable thread with no further changes other than to get your thread fit. You can play with various cutting materials and fluids but that's all mostly cosmetic. Next step is doing the calcs to get the fit, either with a thread gauge or with a thread mic/3 wire configuration.

 

[Someoldguy]

View attachment 1030015 View attachment 1030016 View attachment 1030017 Lot of writing in this thread, but I mentioned earlier that fixing the qctp is priority one. For those that say it’s a “slow motion train wreck” save your breath. I’ve done much harder things in life. For those that are helping, I can’t say thanks enough.
Here is the last thread job. Reground tools, sharpened and fixed the qctp so it doesn’t move. Not perfect but improving. Did a pass, blew off with air, oiled, did another pass. Used 2thou on the crossfeed twice to clean it up. Critiques please.

Good on you, Sir! Asking a question on this forum nearly always results in the thread deteriorating into a public execution beneath the guillotine. I never knew there were so many among us who never make mistakes until I came here.

 

[mram10]

Carl, I’ll go do a full rem700 profile minus chamber and post the pics for you guys to critique.
Someoldguy, lol. There are a few things in life I am pretty good at, yet I would never tell someone wanting to learn anything that would hinder them.
A great gunsmith once said, “they think they’re saving the effing world by Chambering a few rifles”, when talking about the snotty know it alls.

 

[mram10]

Sounds like a personal problem but you did good don't ask questions if you don't want good pr sir I wished I would never offered to help now.

Stan, critiques are welcome, “train wreck” comments aren’t helpful. Your offer was never taken, so no need to worry. Merry Christmas

 

[Someoldguy]

I've received criticism here more than once when I pointed out that in my opinion making a mistake was not the worst thing someone could do.

I assign tucking one's tail and slinking away to be the worst behavior possible. But it's been well established here that my opinion is in the minority.

You gents have yourselves a Merry Christmas.

 

[carlsbad]

Carl, I’ll go do a full rem700 profile minus chamber and post the pics for you guys to critique.

The next part is critiqueable (is that a word) only with measuring tools. Then when it all goes together the final critique is the target.

I've made only 2 strong critiques, and those were both safety. you're moving fast and putting in a lot of hours. Don't get too caught up and hurt yourself. It only takes a second to get your arm wrapped around the chuck. Other than that, put your first photo next to your last and that's a big change. Be patient now as gains will be made more slowly.

PS The flat bottom on your thread groove intrigues me. It is a good feature often used on threads that will require a surface exam such as in the Nuclear industry. A pointed bottom will retain dye and bleed a false indication. Did you put it there on purpose, by accident, or did you end up with an insert with a flat tip?

--Jerry (but you can call me Carl)

https://en.wikipedia.org/wiki/Carlsbad,_California

 

[mram10]

Copy all Jerry
Thanks. I have “never take your hand off the t-handle” going through my head every time I use the chuck, so thanks for that guys. I’ve been pulling up my sleeves and staying away from the chuck. Also, taking my time. I’m very slow still, but watching vids and reading about lathe safety.
Please keep the critiques coming.

 

[mram10]

Stan, what do you mean by gunship?

 

[mram10]

Jay, what do you mean?