To the left or right?
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Thread Bar Project, nothing is going right and I need help
- Thread starter jlsmithseven
- Start date
To the left or right?
I engage the lead screw, then turn the screw a little by pulling the belt ( takes any back lash out), and then adjust the compund and X axis to pick up the thread. Works for me all the time. I do this to pick up threads on a part that has damaged threads that need cleaned up. I repair Model T Ford Wheel hubs this way and they are 32 TPI.
- Joined
- Mar 19, 2014
- Messages
- 2,681
Turn your compound so its travel is the same as the work direction. Turn the lathe on engage the half nuts have the tool bit over the work. Turn off the lathe. Dial the compound and cross until the tool bit aligns perfectly with the thread you are trying to catch. Now retract the tool bit with the cross slide. Do not touch/turn the compound anymore. Just feed the cross until the job is done…Good Luck, Dave.
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I usually line up with the lathe in motion and leadscrew engaged to get it real-world accurate and take up play, then juggle topslide and cross-slide - low speed and blue on the existing thread help.
Dave H. (the other one)
Tool height can be problem but simple to adjust.
Use a small steel thing...A pocket rule or the "v" guide or even a short length of packing strap or hack saw blade.
Hold it vertical between your work and the cutter with lathe stopped.
Using cross slide slowly and gently bring it in until is just touches...If carbide it can break if too tight.
When it just touches it will hold it in place so now look at it from tail stock.
If too high the top will be towards back and too low top towards you and in dead center it will be vertical.
A little practice and you will get it and this is your starting point as fine adjustments based on cutter and material may be needed too.
Sent from my SAMSUNG-SGH-I337Z using Tapatalk
Use a small steel thing...A pocket rule or the "v" guide or even a short length of packing strap or hack saw blade.
Hold it vertical between your work and the cutter with lathe stopped.
Using cross slide slowly and gently bring it in until is just touches...If carbide it can break if too tight.
When it just touches it will hold it in place so now look at it from tail stock.
If too high the top will be towards back and too low top towards you and in dead center it will be vertical.
A little practice and you will get it and this is your starting point as fine adjustments based on cutter and material may be needed too.
Sent from my SAMSUNG-SGH-I337Z using Tapatalk
good directions on how to pick up a thread for whatever reason you need. toz you hold the carriage against the leadscrew to simulate the load against the carriage as it is moved by the leadscrew. so trick question if you are threading toward or away from the chuck. bill
Second comment...
Your instructor should be slapped!
It is his job to properly explain all of this in class before allowing you to touch the machine.
One question with part in hand should have had him assist you by pointing out all of the things pointed out here.
Ask them questions and expect good and expect answers that yiu can understand as that is their JOB!
Sent from my SAMSUNG-SGH-I337Z using Tapatalk
Your instructor should be slapped!
It is his job to properly explain all of this in class before allowing you to touch the machine.
One question with part in hand should have had him assist you by pointing out all of the things pointed out here.
Ask them questions and expect good and expect answers that yiu can understand as that is their JOB!
Sent from my SAMSUNG-SGH-I337Z using Tapatalk
- Joined
- Jan 22, 2011
- Messages
- 8,031
After this is all said and done, and you have completed a passing part, if it is possible and you can arrange it......make another one. This will help cement your new knowledge even more firmly. I don't know how rigid the class structure is, but I wouldn't think the instructor would mind. If that's not possible, get a little notebook and start a journal, making notes about things you did right, and the things you did wrong. It will be to refresh your memory next time you thread. Rarely are threading operations identical, and in real life you won't likely be faced with making a product like that thread bar (which btw I thing is an excellent teaching exercise), but you can learn a lot from it.
- Joined
- Jan 16, 2017
- Messages
- 216
I'm kinda confused on what you mean hold the saddle to the right means? Originally, when I tried to re-catch threads, I was turning the compound so it would just barely touch the right side of the thread. All I turned was the x-slide and then the compound and fed it in and it barely touched the right. I ran it across in the air and it looked fine.
Last edited:
- Joined
- Feb 7, 2014
- Messages
- 90
I didn't read every response to your thread, there were A LOT of them. I assume you are simply making a bar with threads for the sake of being able to demonstrate you can cut threads? That would make the most sense to me. When I was in college they had us make practical items that were actually useful for something. We made a no twist clamp for example and that was my thread training. To be honest other than a fairly automatic machine I used to set up at a shot, and only because I was the only guy there smart enough to figure it out, that was the only threading I've ever done by the book so to speak. Setting up that machine was a bit different from just using a lathe because it was designed just to cut threads and do it in one cut. Also, my clamp use the type of thread that is used in a clamp...which is, of course, different from typical screw or bolt threads...so I don't think what my threading training taught me is the same thing as you have to accomplish.
That being said, I think Mikey said it best when he pointed out that you CAN'T take it out and keep concentricity. They used to pound into us the importance of it, especially in lathe work but actual demonstrations didn't get into a lot of detail about it. I don't real the instructor showing how to check as we went to make sure thing were right, WITHOUT taking it out of the machine or what to do if we didn't have a choice. When class is done you're done.... You have to take it out. For sure, once you start cutting threads, you really can't take it out and think you can put it back in and it work. I'm sure some really good and really talented guys can do this but I just happened to have the knack for basic machining while going to school for engineering drafting and design. The only reason we had to take the machine tool sequence was to make us better designers. Most of the guys barely make it through the class, some were from the outside companies getting certifications and about a quarter were people from the "machinist program". So we were mostly looked at as, "they just need to get by and get the general concept, they aren't going to look for work making chips". But I did one time when there was one of the many layoffs at one of the many companies I worked at in the small area I lived in. Work was very seasonal but there was no season...LOL But I, again, kind of had a knack for it, probably because I'd worked on cars all my life till then and had a fair understanding of machined parts and therefore machine tools.
I'm not going to be able to help you much with your project but I wanted to say that you came to the right place. Some of these guys, for a hobby board, are just incredible machinists! I mean WAY over my head just in general conversation! If anyone can help you get through your projects they can. But listen, you ARE going to have that "ah ha" moment and this will become far easier. It might help to think of the machines as just a tool, no different than a chisel or a wrench. They do a job and that's it. If you use the wrong wrench or don't hold it squarely, it'll slip and round the head of the bolt and probably bust your knuckles LOL. This isn't rocket science, don't get bothered because you're struggling. Most if this is not that complicated and these guys will help you with the little blocks that you run into. I shocked everyone when I aced the class and made everything perfectly and got all points available. I had better than a 4 point if you consider getting extra points here and there for test questions or extra projects. But I really thought it was cool what you could accomplish with fairly simple tools. We also learn to understand the basics of CNC programming and machining. I ended up excelling at that in the field too. This isn't that hard and you WILL get it. Just remember that there may be more than one way to do just about anything..but sometimes there's only one way. If anything moves while you're cutting...it's probably scrap. Almost every time unless you started with a lot more steel than you needed. LOL.
Keep the faith, try not to get too frustrated, there's a learning curve to peeing in the toilet, so there'll certainly be a learning curve to making a precision work piece.
Wayne
That being said, I think Mikey said it best when he pointed out that you CAN'T take it out and keep concentricity. They used to pound into us the importance of it, especially in lathe work but actual demonstrations didn't get into a lot of detail about it. I don't real the instructor showing how to check as we went to make sure thing were right, WITHOUT taking it out of the machine or what to do if we didn't have a choice. When class is done you're done.... You have to take it out. For sure, once you start cutting threads, you really can't take it out and think you can put it back in and it work. I'm sure some really good and really talented guys can do this but I just happened to have the knack for basic machining while going to school for engineering drafting and design. The only reason we had to take the machine tool sequence was to make us better designers. Most of the guys barely make it through the class, some were from the outside companies getting certifications and about a quarter were people from the "machinist program". So we were mostly looked at as, "they just need to get by and get the general concept, they aren't going to look for work making chips". But I did one time when there was one of the many layoffs at one of the many companies I worked at in the small area I lived in. Work was very seasonal but there was no season...LOL But I, again, kind of had a knack for it, probably because I'd worked on cars all my life till then and had a fair understanding of machined parts and therefore machine tools.
I'm not going to be able to help you much with your project but I wanted to say that you came to the right place. Some of these guys, for a hobby board, are just incredible machinists! I mean WAY over my head just in general conversation! If anyone can help you get through your projects they can. But listen, you ARE going to have that "ah ha" moment and this will become far easier. It might help to think of the machines as just a tool, no different than a chisel or a wrench. They do a job and that's it. If you use the wrong wrench or don't hold it squarely, it'll slip and round the head of the bolt and probably bust your knuckles LOL. This isn't rocket science, don't get bothered because you're struggling. Most if this is not that complicated and these guys will help you with the little blocks that you run into. I shocked everyone when I aced the class and made everything perfectly and got all points available. I had better than a 4 point if you consider getting extra points here and there for test questions or extra projects. But I really thought it was cool what you could accomplish with fairly simple tools. We also learn to understand the basics of CNC programming and machining. I ended up excelling at that in the field too. This isn't that hard and you WILL get it. Just remember that there may be more than one way to do just about anything..but sometimes there's only one way. If anything moves while you're cutting...it's probably scrap. Almost every time unless you started with a lot more steel than you needed. LOL.
Keep the faith, try not to get too frustrated, there's a learning curve to peeing in the toilet, so there'll certainly be a learning curve to making a precision work piece.
Wayne