5/16 30tpi screw?

J

Jeff in ND

Plastic

Joined

Dec 16, 2002

Location

Valley City, ND, USA

• Mar 12, 2004

• #1

I need to make a 5/16 - 30 tpi screw for a Stevens 44 I am working on. Problem is my lathe does not have a 30 tpi threading setting, it jumps from 28 to 32tpi.

Is there some trick I can use to make a 30tpi screw on a lathe without a 30tpi setting?

Thanks
Jeff in ND

 

S

Skeeter

Aluminum

Joined

Dec 10, 2002

Location

Marshall, Tx USA

• Mar 12, 2004

• #2

Hi Jeff,

Try this URL. It is Varmint's Al's page. He has a program that you can download. It will let you cut many threads with your present gear units. Program is Gears.zip.

I hope it works for you.

Good luck on your project.

http://www.varmintal.com/alath.htm#Cutting_Odd_Threads

 

GGaskill

Titanium

Joined

Feb 14, 2001

Location

Central AZ

• Mar 12, 2004

• #3

How many threads engage in the hole? If only a few, make the screw from soft material with 32 tpi, lube it with some moly grease, and turn it in. It will stretch as it is turned in. Don't try this if there are a lot of threads engaged as you will probably not be able to fully seat the screw.

 

lathefan

Titanium

Joined

Nov 7, 2003

Location

Colorado

• Mar 14, 2004

• #4

If your lathe will cut metric threads, 30tpi is just about exactly .85mm pitch.

 

T

TRAILBREAKER

Plastic

Joined

Mar 12, 2004

Location

Minnesota,USA

• Mar 14, 2004

• #5

The only lathe that I have seen that will cut 30tpi is a monarch 10EE.Not including CNCs

 

lathefan

Titanium

Joined

Nov 7, 2003

Location

Colorado

• Mar 14, 2004

• #6

Of course this is the advantage to a change gear lathe, it can be geared to cut virtually any thread.According to Martin Cleeve in his book "Screw Cutting in the Lathe" a 20 gear change gear set can be set up in combinations of 2, 4, or 6 gears to achieve approximately 750,000 different thread pitches. For an 8 tpi leadscrew, any gears set up in a ratio of 4/15 will cut 30 tpi, for example 16/60, 20/75 etc. If you set your quick change box to cut the same tpi as your leadscrew(i.e. 8 tpi for a 8 tpi leadscrew), and if you can change the gearing between your spindle and the change gear box to equal the basic 4/15 ratio, then the lathe will cut 30 tpi.


[This message has been edited by lathefan (edited 03-14-2004).]

 

J

Jeff in ND

Plastic

Joined

Dec 16, 2002

Location

Valley City, ND, USA

• Mar 18, 2004

• #7

Thanks for the info guys, I have a few options to look into now.

Good Hunting
Jeff in ND

 

Dave Milosevich

Aluminum

Joined

Feb 8, 2001

Location

Sequim, Washington, USA

• Mar 19, 2004

• #8

Re: Only lathe... The Clausing-Colchester 13" and 15", 80XX series lathes cut 30TPI without changing stock gears.

The thread I've yet to see on a lathe as standard is 25TPI.

As to 30TPI - it is also used on Winchester pre '64 Model 70's. The cocking piece screws on to the firing pin and the thread used there is 9/32" X 30TPI. Also, the stud that screws into some of the accessory rails of the target rifles uses the same thread.

FWIW

 

G

green frog

Cast Iron

Joined

Mar 9, 2001

Location

Lynchburg, VA, USA

• Mar 24, 2004

• #9

Also, the old Ideal and Lyman Tru-Line Jr and 310 tool dies are 30 tpi! That's a tough tap or die to find as well.

GF

 

D

doc

Hot Rolled

Joined

Mar 12, 2001

Location

alvaton,ky

• Apr 3, 2004

• #10

plug for atlas /crftsmn quick change which HAS 30 TPI ....came in handy for mod 12 win. barrel thrds a few times.....win seemed to like that particular thrd..........there is value in keeping an old loose change lathe around ...

best wishes
docn8as