Shop Floor Talk  

Go Back   Shop Floor Talk > Welding and Metalworking Forums > Machining

SFT Search:   
Reply
 
Thread Tools Display Modes
  #1  
Old 11-27-2017, 07:06 PM
toprecycler's Avatar
toprecycler toprecycler is offline
Elite Member
 
Join Date: Jan 2009
Location: Petoskey, Michigan
Posts: 2,727
Default Lathe threading...

First day on the job and I am shadowing the junior machinist. We had to make a replacement to shaft for a hydraulic cylinder. Turn one end 7/8” shaft down to 1/2” dia. 1 1/2” length. And then thread the end for 20 tpi for 5/8” long.

All seemed straightforward enough til he started threading. I was taught to angle the compound slide to 29 degrees and use that to feed in. Use the cross slide to back the cutter out at the end and then move carriage back for next cut, feed in cross slide back to 0, and adjust the compound for next cut.

We are using quick change tool posts with threading insert tooling. This is all new to me now. The compound is set parallel with the ways, and seems only to be used to sneak up on shoulders when done with carriage feed. Only the cross slide was used in feeding the threading tool bit in.

Later, that was the last machining job of the day, so I was told to go practice on my lathe and turn something to learn the lathe controls. I took the old shaft and machined the threaded end. I got the threads to work, but was not happy how they actually looked. They seemed off, as one side was wrong angle. It may have been that I did not verify that the threading tool was perfectly perpendicular to the shaft and I think the compound is off slightly. Previously they mostly used the lathe to chuck up parts to clean up with Emory cloth and or use spray metal weld build up on certain few jobs per year. I had to clean up the thread dial to be able to read it, so I know it has not been used for threading in a while.

So my question is, is it Good practice to only use the cross slide feed when threading using threading insert tooling. It seems to me that the reason I was taught to use the compound slide was so you only cut on one side of the hand ground tool but mostly, and if you were off a little in the grinding of the 60 degree cutting bit, it would not make as big a difference in final threads. I would think that the insert tooling is ground to more precise angles vs hand grinding a tool bit and can handle taking chips out on both sides of the bit at once?

Now on to do some research on my lathe at work. It is a Summit. Will have to get actual size later.Click image for larger version

Name:	IMG_4795.JPG
Views:	65
Size:	158.5 KB
ID:	142312


Sent from my iPhone using ShopFloorTalk mobile app
__________________
Brian

You don't know what you don't know.

"It's what you learn after you know it all that counts." John Wooden
Reply With Quote
  #2  
Old 11-27-2017, 07:12 PM
toprecycler's Avatar
toprecycler toprecycler is offline
Elite Member
 
Join Date: Jan 2009
Location: Petoskey, Michigan
Posts: 2,727
Default Lathe threading...

New boss asked how first day was going and I let him know what I was doing. I mentioned that I was having to borrow quick change tooling from other guys lathe, and I would have to adjust the height nuts for my lathe, and he thought about it, and said he will probably order me a new quick change tool post and new holders since he was told that this one is wearing out. The handle to tighten is turning more that it should because the gears inside are wearing out? At least that’s what I was told by Co workers. So I might come in tomorrow and have new tooling to work with. big change from my old job in this way.

I was starting to design a hammer to make. I figured if they want me to make some chips to learn the lathe, might as well make some useful tools in the learning time. Want to make a hammer with different screw in heads. Figure one brass, aluminum, nylon, and maybe a lead one. Anyone have any leads on plans for such a hammer?

Sent from my iPhone using ShopFloorTalk mobile app
__________________
Brian

You don't know what you don't know.

"It's what you learn after you know it all that counts." John Wooden
Reply With Quote
  #3  
Old 11-27-2017, 07:13 PM
digger doug's Avatar
digger doug digger doug is offline
Not to be used as a Flotation Device
 
Join Date: Jan 2008
Location: NW Pa
Posts: 9,786
Default

I was taught the way you were taught and for the same reason.

When you say insert tooling, do you mean a multiple thread laydown
insert ? Or just a single "V" ?


BTW on such a small thread (that looks like a common size)
They don't have a die head laying around ?
Reply With Quote
  #4  
Old 11-27-2017, 07:24 PM
milomilo's Avatar
milomilo milomilo is offline
Auction Addict
 
Join Date: May 2010
Location: Wheatland, Wyoming
Posts: 12,103
Default

Probably does not help much but, I do my threading just like they are doing. Just seemed easier in the set up to me. You do have to have it perfectly square to the part this way. I have done it the other way, just like this way better.
__________________
Chris

“In order to become the master, the politician poses as the servant.” Charles de Gaulle
Reply With Quote
  #5  
Old 11-27-2017, 07:57 PM
digr's Avatar
digr digr is offline
The Real Deal
 
Join Date: Apr 2005
Location: Duluth MN
Posts: 7,011
Default

Here are some hammers I made
__________________
Drawing by Smartdraw
Reply With Quote
  #6  
Old 11-27-2017, 08:06 PM
greywynd's Avatar
greywynd greywynd is offline
I can dig it
 
Join Date: Dec 2005
Location: Peterborough, Ontario
Posts: 3,388
Default

Either way will work, especially on small threads like a 1/2-20.

Verify your bit is square to thebwork with a 60 degree gauge (I always called them fishtail gauges, can't remember the proper name!)

Doing it with the compound parallel, lock the compound and just use the cross slide for depth. Use cutting oil, and don't be afraid to run a little faster on the rpm then you would with hss if you can.

As you get close to final size, taking lighter cuts should help on the finish.
Reply With Quote
  #7  
Old 11-27-2017, 08:51 PM
toprecycler's Avatar
toprecycler toprecycler is offline
Elite Member
 
Join Date: Jan 2009
Location: Petoskey, Michigan
Posts: 2,727
Default

Quote:
Originally Posted by digger doug View Post
I was taught the way you were taught and for the same reason.



When you say insert tooling, do you mean a multiple thread laydown

insert ? Or just a single "V" ?





BTW on such a small thread (that looks like a common size)

They don't have a die head laying around ?


Single v bit. Three cutting edges on insert, dull one and rotate as needed.

I think they will cut more with lathe just because? This one could have used a die just as easily. I guess sometimes, we may make special diameters but still use a common fine thread. They didn’t worry about measuring with wires though. Just cut Til they look close and start checking the nut going on. When it threads in easy, your done.


Sent from my iPhone using ShopFloorTalk mobile app
__________________
Brian

You don't know what you don't know.

"It's what you learn after you know it all that counts." John Wooden
Reply With Quote
  #8  
Old 11-27-2017, 08:55 PM
toprecycler's Avatar
toprecycler toprecycler is offline
Elite Member
 
Join Date: Jan 2009
Location: Petoskey, Michigan
Posts: 2,727
Default

Quote:
Originally Posted by greywynd View Post

Verify your bit is square to thebwork with a 60 degree gauge (I always called them fishtail gauges, can't remember the proper name!)

As you get close to final size, taking lighter cuts should help on the finish.

This is where I am thinking I messed up. I did not verify that the bit was square to the work. I did take lighter cuts near the end though. Thanks for the reply.



Sent from my iPhone using ShopFloorTalk mobile app
__________________
Brian

You don't know what you don't know.

"It's what you learn after you know it all that counts." John Wooden
Reply With Quote
  #9  
Old 11-27-2017, 08:58 PM
toprecycler's Avatar
toprecycler toprecycler is offline
Elite Member
 
Join Date: Jan 2009
Location: Petoskey, Michigan
Posts: 2,727
Default

Quote:
Originally Posted by digr View Post
Here are some hammers I made


Thanks for the reminder of this thread, Ted.


Sent from my iPhone using ShopFloorTalk mobile app
__________________
Brian

You don't know what you don't know.

"It's what you learn after you know it all that counts." John Wooden
Reply With Quote
  #10  
Old 11-27-2017, 09:00 PM
greywynd's Avatar
greywynd greywynd is offline
I can dig it
 
Join Date: Dec 2005
Location: Peterborough, Ontario
Posts: 3,388
Default

Another thing to watch is the tip on inserts, they often have different radii depending on the tpi that you're cutting. Bigger radius for a 'coarser' thread.

Double check the height of the tool to centre too.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Web Search:

All times are GMT -5. The time now is 10:56 AM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2018, vBulletin Solutions, Inc.