Clausing 6900 series Left hand lead screw and nut replacement.

[Stephen S]

I am replacing lead screw and nut on Clausing 6900 series. what material will be best for the lead screw?
Found LH lead screw on Mc Master Carr. and eBay.
E bay lead screw made of Plain Steel. prices is cheap. Acme Threaded Rod Left Hand LH 1/2-10 x 3ft. Plain Steel. US $19.99.
Mc Master Carr made of Carbon steel 3 ft. $44.94. Black-Oxide 4140 Alloy Steel 3 ft. $17.56. 304 Stainless Steel 3 ft. $72.44
Also found Clausing 4900-37, DL-453, 10" & 12" Lathe Cross Feed Nut 1/2"-10 Left Hand ACME. US $65.00

Item description from the seller​

I have had a buyer tell me that it fit his 6300 Series - part number 990-069.

 

[benmychree]

Be advised that the items of screws are not likely precision in the manner of accurate lead, not suitable for measuring.

 

[Stephen S]

Thanks for your response.
Helped me out.

Thread Size

Lg.

No. of Thread Starts

Speed Ratio

Travel Distance per Turn

Thread Fit

Fastener Strength Grade/Class

Hardness

Tensile Strength, psi

Specifications Met

Each

1/2"-10

3 ft.

1

1:1

0.1"

Class 2G

Grade 2

Rockwell B61

64,000

ASTM A108

98935A823

13.63

After doing more research, McMaster Carr lead screw is class 2G
For precision machining 2C or 8E would be desirable. Unfortunately, I have not found this on McMaster Carr.

The issue that I am facing, Clausing quoted me $1,213.68 for SCREW & NUT ASSY for Q-551S.
While I am doing this i was going to replace the threading gears. DL-628 GEAR (R), $104.40 and Q-384 $109.41
Total $1455.27.
I paid $1850 for the lathe 22 years ago.
May be better served to buy another lathe and sell this one.

 

[jwmelvin]

Contact Green Bay Manufacturing and see what their price would be?

greenbaymfgco.com

Edit: oh, sorry, looks like class 2G is their standard. But maybe worth calling to see if they also do higher precision?

 

[jwmelvin]

Also call Roton and see what specs they can do.

 

[benmychree]

Usually most of the wear is on the nut, does the screw look badly worn? maybe best to buy the aftermarket nut and use it as-is.

 

[Ischgl99]

I agree with benmychree, check and make sure the leadscrew is worn, the leadscrew in my Burke Millrite was fine and it just needed the nut replaced. If you do need to replace the leadscrew too, these guys would have what you need.

Precision Lead Screws

REMPCO leadscrews are manufactured to exceed the highest industry standards. Efficiencies up to 80% are achievable with our precision leadscrews.

www.rempco.com

 

[Stephen S]

Usually most of the wear is on the nut, does the screw look badly worn? maybe best to buy the aftermarket nut and use it as-is.

After sleeping on, and your suggestion I decided that I will start with the nut replacement.
Will go from there.

 

[Stephen S]

I agree with benmychree, check and make sure the leadscrew is worn, the leadscrew in my Burke Millrite was fine and it just needed the nut replaced. If you do need to replace the leadscrew too, these guys would have what you need.

Precision Lead Screws

REMPCO leadscrews are manufactured to exceed the highest industry standards. Efficiencies up to 80% are achievable with our precision leadscrews.

www.rempco.com

Thanks for the information on the website. I added this to the folder for this project for future reference.
I visited the website. I will get a quote from them in the event I change the lead screw.

 

[G-ManBart]

The issue that I am facing, Clausing quoted me $1,213.68 for SCREW & NUT ASSY for Q-551S.
While I am doing this i was going to replace the threading gears. DL-628 GEAR (R), $104.40 and Q-384 $109.41
Total $1455.27.
I paid $1850 for the lathe 22 years ago.
May be better served to buy another lathe and sell this one.

I have a copy of the dealer master parts list for the 6900 series (and two 6913s) and I can't find that Q-551S part anywhere. What's it for and do you know the manual page you got that number? I ask because I know a gentleman who bought all of the Clausing parts when they closed the previous service center and he's got all kinds of parts stashed away. I have to call him to check on a couple of things I'm looking for anyway, so if I can reference a part I have in the manual I'd be happy to see if he's got what you're looking for.