Metal Lathe for Multi-start threads - International Association of Penturners
     International Association of Penturners
Pens for Service Members
 
Support The IAP

Go Back   International Association of Penturners > Community Forums > Shops, Jigs, Fixtures & Tools
  Forgot Password
Register FAQ Members List Search Today's Posts Mark Forums Read
Shops, Jigs, Fixtures & Tools Show off and discuss your workshop and everything in it.


Logged on members can hide ads!

Welcome to penturners.org!

You've found the home of The International Association of Penturners. You are currently viewing our site as a guest, which gives you limited access to view discussions, photos, and library articles.

Consider joining our community today. You'll have full access to all of our content, be able to enter our contests, find local chapters near you, and post your questions and share your experience with our members all over the world.

Membership is completely free!!

If you have any problems with the registration process or your account login, please contact us.

Reply
 
LinkBack Thread Tools Display Modes
Old 03-23-2018, 11:02 PM   #1 (permalink)
 
Join Date: Aug 2010
Location: Florida
Posts: 22
Photos: 0

Default Metal Lathe for Multi-start threads

Hi All,
So, 7 years have passed since I logged in last. I bought a Micro-Mark 7x16 lathe specifically for making multi-start threads and realized later that 12 TPI is too fine. I made some pretty impressive segmented pens (if I do say so myself) but stopped making pens due to raising a family and frustrations with kit components. Now I'd like to get back into this.

Can anyone tell me if they have successfully used a small lathe (9x19, 10x22, etc) for cutting multi-start threads for kitless pens? I found a nice discussion of it on Silver Hand studio's site suggesting that 8TPI is acceptable but seeming to also suggest that reverse is necessary.

Any advice is greatly appreciated!
__________________
Dave
Northeast Florida
lign is offline   Reply With Quote Top
Old 03-24-2018, 04:37 AM   #2 (permalink)
 
randyrls's Avatar
 
Join Date: Feb 2006
Location: Harrisburg, PA 17112
Posts: 3,910
Photos: 61

Default

I checked my normal carry pen and it has normal right hand threads. That is a sample of only one though. I have not made any pen sections, Sorry.
__________________
Randy S.
~~~~ Add Your Postal Code and Country to the UserCP ~~~~~

I expect to pass through this world but once. Any good, therefore, that I can do or any kindness I can show to any fellow creature, let me do it now. Let me not defer or neglect it for I shall not pass this way again. -- Stephen Grellet
randyrls is offline   Reply With Quote Top
Old 03-24-2018, 06:40 AM   #3 (permalink)
 
More4dan's Avatar
 
Join Date: Mar 2016
Location: Katy, TX
Posts: 926
Photos: 5

Default

Iíve been turning on a 7 x 10 mini metal lathe for about 2 years now. For my early kitless pens, I cut the outer threads with the lathe and used the lathe to make my own taps for the inner threads. What a pain it was. I learned a lot. Mostly what I learned was I got better results with using taps and dies with guides that mount in the tailstock. It is also much quicker. For double threads you will have to find a way to advance the compound slide and retract the cross slide both to start in the correct place for the second set of threads. Or you could leave the slides alone and figure out how to turn your material 180 degrees w/o moving it into the chuck. You could mark the material at one jaw of the chuck and readjust to the mark for each jaw moving it 120 degrees for a triple thread. You would cut the same thread 3 times but just move the material. It wouldnít take me many times messing up my blanks before I got into the next group buy for a set of taps and dies. PM me if you have questions, Iíll send you my cell number.

Danny


Sent from my iPhone using Penturners.org mobile app
Likes: (1)
More4dan is offline   Reply With Quote Top
Advertisement
Old 03-24-2018, 07:55 AM   #4 (permalink)
 
Join Date: Apr 2017
Location: Indiana
Posts: 351
Photos: 0

Default

I cant help with this but there is a maker on here (forget who) that makes a modified acme thread that is very cool. It by passes some of the problems associated with triple starts.
Hereís a pic i saved.
Likes: (1)
PatrickR is online now   Reply With Quote Top
Old 03-24-2018, 09:49 AM   #5 (permalink)
 
magpens's Avatar
 
Join Date: Feb 2011
Location: Coquitlam, BC, Canada
Photos: 63

Default

The maker referred to by Patrick is jalbert.

In doing triple start on a lathe, I think you have significant challenges. . I believe there have been threads here about doing that; could be the same maker, or perhaps skiprat.

I cannot see how reverse would make things any easier.
__________________
Mal

Kids rule the world !!! .... eventually if not already !







Last edited by magpens; 03-24-2018 at 09:50 AM.
magpens is offline   Reply With Quote Top
Old 03-24-2018, 10:13 AM   #6 (permalink)
 
lorbay's Avatar
 
Join Date: Jul 2009
Location: BC. Canada
Posts: 3,016
Photos: 134

Default

Here is the link to Skip-Rats triple start threading.
http://content.penturners.org/librar..._threading.pdf

Lin
__________________
"If you come to a fork in the road Take It."
Yogi Berra.
Likes: (1)
lorbay is online now   Reply With Quote Top
Old 03-24-2018, 06:57 PM   #7 (permalink)
 
Join Date: Jul 2013
Location: Owensboro, KY
Posts: 262
Photos: 0

Default

Dave,

Some perspective:

Using 12 tpi gearing is going to give you a fine 36 tpi triple triple start.That is pretty fine, but I know at least one pen maker who uses it.

Since most of us tend to think metric, the two most common triple start tap/die pitches that are ordered are .75 and .8 mm if I'm not mistaken. A 0.8mm pitch translates into 31.8tpi. So if you set up your change gears for either 10 or 11 tpi you will be right in the ballpark (i.e. 30 or 33). If you have a 21 tooth gear you can set up for almost exactly 0.8mm.

24 tpi is a little bit coarse. What happens when you set up the Sieg 7X lathes for 8tpi is, due to the fact that you are driving the carriage a long distance (1/8 inch or 2 turns of the leadscrew) for each turn of the spindle, it tends to kick out of gear when driven forward. If you turn the spindle in reverse and cut the thread with the tool inverted, this will not happen. Another work-around is to drive the system by turning the leadscrew rather than the spindle.

Triple start threading isn't hard. It's slower than taps and dies, but it frees you from being locked in to specific diameters. Like anything else its a matter of practice, and well worth learning, even if you eventually buy the tap and die sets. Believe me, you won't want to use that $100 die set on a Damascus blank.

Take a look at Skiprat's tutorial for sure.

Hope this helps.

Bill
Likes: (2)
bmachin is offline   Reply With Quote Top
Old 03-24-2018, 10:11 PM   #8 (permalink)
 
magpens's Avatar
 
Join Date: Feb 2011
Location: Coquitlam, BC, Canada
Photos: 63

Default

Gee ... thanks, Bill ... that is very illuminating !

I would never have dreamed about the reverse trick ... as you may have read above, I did not know this.

I do have a 7x lathe so someday I might have to use this trick.
__________________
Mal

Kids rule the world !!! .... eventually if not already !







Last edited by magpens; 03-24-2018 at 10:14 PM.
magpens is offline   Reply With Quote Top
Old 03-24-2018, 11:05 PM   #9 (permalink)
 
Join Date: Aug 2010
Location: Florida
Posts: 22
Photos: 0

Default

Thanks so much for the helpful replies so far! To be honest, sometimes my hobbies are just excuses to buy really cool tools. I'm debating the possibility of getting a bigger lathe that can do 8 TPI. I am reluctant to be stuck with the size of a tap and die. When I spend 30 to 40 hours on a single pen, I HATE HATE HATE when my equipment ruins it. That's why I sold my Grizzly drill press and bought a Jet 17" drill press with laser. That's also why I sold my Grizzly lathe and bought a Powermatic. (BTW, I have other Grizzly tools I love and I don't hate Grizzly).

The picture attached is one of the last pens I made years ago. The scallops are sterling silver and jade and the body is ebony and Mother-Of-Pearl acrylic. I made it a heptagon (7-sides) because the guy I made it for wanted no doubt that it was one-of-a-kind.

When I spend this kind of time to make a pen, I don't want to be limited by anything, including sizes or crappy components. I'm a true pen lover (I own Pelikans, Parkers, and etc that cost me a fortune). I quit making pens because I was just so frustrated. I never made pens that truly measured up to the works of art I wanted to make.

Rant over.

I did read Skiprat's awesome material, and I realize that if I do this, I'll have a big learning curve.

I'm considering a number of options, all the way from Grizzly's variable speed 8x16 to their monster combo mill/lathe that can cut 4 TPI and costs $2,350. Any thoughts?
Attached Thumbnails
checkerboard1.jpg  
__________________
Dave
Northeast Florida
lign is offline   Reply With Quote Top
Old 03-24-2018, 11:22 PM   #10 (permalink)
 
magpens's Avatar
 
Join Date: Feb 2011
Location: Coquitlam, BC, Canada
Photos: 63

Default

Dave, that is one beautiful pen !!!! . I am certainly glad you decided to rejoin us.
__________________
Mal

Kids rule the world !!! .... eventually if not already !






Likes: (1)
magpens is offline   Reply With Quote Top
Related Content
Logged on members can hide ads
Reply

Bookmarks

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
Trackbacks are On
Pingbacks are On
Refbacks are On


All times are GMT -5. The time now is 11:32 AM.

Powered by vBulletin® Version 3.7.6
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.6.0

Content Copyright © 2003-2018 by Penturners.org, LLC; All Rights Reserved
Terms Of Service   Acceptable Use Policy