Hardinge Cataract screw cutting attachment

L Vanice · May 28, 2012

I have finished replacing missing parts on two Hardinge Cataract screw cutting attachments. And I just finished converting a Hardinge 1946 model 9" slide rest to work for screw cutting. Today I took the first cuts with it.

The pre-1946 Hardinge 7" and 9" slide rests all have extensions on the longitudinal feed screw, meant for use with the screw cutting attachments. But Hardinge designed a new slide rest in 1946 to go with the new dovetail bed lathes now known as the DV-59. Hardinge also made these slide rests with a base to fit any of the older 9" split bed lathes. The 1946 slide rest did not have provision for use with the screw cutting attachment. So I had to convert one to work, which was pretty simple in concept.

I bored a hole in the end of a longitudinal feed screw and soldered in a long plug. Then I turned the plug to the same dimensions as the end of the pre-1946 feed screws. I fitted a cast iron guide bushing to the hole in the left end of the slide. The only real trick was correcting the alignment of the feed nut so that the feed screw did not bind in the nut when constrained by the new bushing.

Here are some pictures, as many as I can add to one post.

Larry

L Vanice · May 28, 2012

More pictures. I set up the gears for 40 TPI and cut a 5/16-40 thread. It worked, but it makes the quick change gear box for threading seem like a great idea.

The old Hardinge Cataract catalogs include tables of change gears for pitches from 5 to 160. The tables are different for the no. 3, 4 and 5 lathes because the larger the spindle, the larger the spindle gear. I have a 127 tooth gear, but there are no tables for using it to cut metric threads. Another future project, perhaps to wait until I actually need to cut a metric thread.

All of the Cataract beds have the holes in the end to mount the screw cutting attachment. I have never seen a circa 1940 and later Hardinge bed, the "skirted" style, fitted for screw cutting. The skirted beds were, however, available with the rear T-slot for the thread chasing attachment. My ESM-59 has the thread chasing attachment, which was one of the main reasons I bought it.

When the dovetail beds were introduced in 1946, all of them were machined on the rear for the thread chasing attachment. It was a different attachment from that found on the split beds, and in particular the hobs, or lead screw masters, were different. After a few years, the dovetail bed pattern still had provision for thread chasing, but the bed machining was not done. The 1960 major redesign of the DV-59 left no provision for single point threading.

Larry

D. Ravizza · May 28, 2012

Nice work Larry!

It's nice to see a Cataract lathe set up for thread cutting.

How is the threading tool engaged/disengaged from the work?

Dan

L Vanice · May 28, 2012

D. Ravizza said:
...How is the threading tool engaged/disengaged from the work?

Dan

By using the cross feed.

I have the same sort of attachments for my Levin and Derbyshire watch lathes. I only use them if there is no choice. It is a slow process to set up the gearing and cut the threads. With the watch lathes, I use a triple slide rest with the bottom slide set at 30 degrees to the bed. I feed with the bottom slide and retract and return with the top slide. It is a better system than using a conventional slide rest like the one on the Hardinge. Pictures are of a Levin set up for threading.

The thread chasing attachments are much faster, especially for repetitive fine pitch work in brass, where the thread can be cut in one pass.

Larry

traditional-tools · May 29, 2012

Wow, that's a great looking machine! Nice work!

L Vanice · May 31, 2012

Today I set up the gears and cut a 5/16-48 RH thread. The gear train is a double reduction for pitches of 44 TPI and finer. The rear arm idler gear is not used except for left hand threads on the finer pitches.

I previously showed the gearing for 40 TPI RH, which is single reduction. The coarser pitches use the rear idler gear for right hand threads.

I tried reversing the spindle without retracting the cutter and it worked OK. I have a new feed screw and nut in this slide rest and I had set up the gears with about zero backlash. So the cutter nicely followed the previously cut thread when I reversed. Of course, the cutter just rubs in the threads without cutting when reversing, so the threads are not damaged. Doing it that way is a real timesaver.

I am thinking of making a compound slide/retracting tool holder (kind of like the HLV-H) to sit on top of the normal top slide. Then i can feed the cutter at the preferred 29 degree angle instead of straight in.

Larry

robinr · May 31, 2012

Hi Larry,

I don't know if you are familiar with the swing up threading tool, but it should be a lot easier to construct than a retracting tool holder. Here is a link to a thread on the subject over on the HSM site, it contains links to video's of it in use, cutting both right and left hand threads. Swing threading tool - The Home Shop Machinist & Machinist's Workshop Magazine's BBS

glennview · Dec 7, 2017

Beautifully maintained and restored equipment

L Vanice said:
I have finished replacing missing parts on two Hardinge Cataract screw cutting attachments. And I just finished converting a Hardinge 1946 model 9" slide rest to work for screw cutting. Today I took the first cuts with it.

The pre-1946 Hardinge 7" and 9" slide rests all have extensions on the longitudinal feed screw, meant for use with the screw cutting attachments. But Hardinge designed a new slide rest in 1946 to go with the new dovetail bed lathes now known as the DV-59. Hardinge also made these slide rests with a base to fit any of the older 9" split bed lathes. The 1946 slide rest did not have provision for use with the screw cutting attachment. So I had to convert one to work, which was pretty simple in concept.

I bored a hole in the end of a longitudinal feed screw and soldered in a long plug. Then I turned the plug to the same dimensions as the end of the pre-1946 feed screws. I fitted a cast iron guide bushing to the hole in the left end of the slide. The only real trick was correcting the alignment of the feed nut so that the feed screw did not bind in the nut when constrained by the new bushing.

Here are some pictures, as many as I can add to one post.

Larry

View attachment 52968 View attachment 52969 View attachment 52970 View attachment 52971 View attachment 52972

Larry

Beautifully maintained and restored equipment! Where the heck did you come up with new feed screws and nuts? Perhaps a needle bearing would be another option instead of that cast iron bushing. I have some to spare; I would be glad to send you a couple. No doubt you have lathes with the rear thread chasing attachment as well. Have you found or written articles on working with the rear thread chasing attachment? If so, I would like to read them.

glenn

Giglio_A · Nov 5, 2019

L Vanice said:
More pictures. I set up the gears for 40 TPI and cut a 5/16-40 thread. It worked, but it makes the quick change gear box for threading seem like a great idea.

The old Hardinge Cataract catalogs include tables of change gears for pitches from 5 to 160. The tables are different for the no. 3, 4 and 5 lathes because the larger the spindle, the larger the spindle gear. I have a 127 tooth gear, but there are no tables for using it to cut metric threads. Another future project, perhaps to wait until I actually need to cut a metric thread.

All of the Cataract beds have the holes in the end to mount the screw cutting attachment. I have never seen a circa 1940 and later Hardinge bed, the "skirted" style, fitted for screw cutting. The skirted beds were, however, available with the rear T-slot for the thread chasing attachment. My ESM-59 has the thread chasing attachment, which was one of the main reasons I bought it.

When the dovetail beds were introduced in 1946, all of them were machined on the rear for the thread chasing attachment. It was a different attachment from that found on the split beds, and in particular the hobs, or lead screw masters, were different. After a few years, the dovetail bed pattern still had provision for thread chasing, but the bed machining was not done. The 1960 major redesign of the DV-59 left no provision for single point threading.

Larry

View attachment 52973 View attachment 52974 View attachment 52976 View attachment 52975

Larry,

What does the catalog say the change gear set includes as a standard for a Cataract 37 and 47 headstocks? I would like to complete the set that I started with the purchase from you. Thanks

L Vanice · Nov 5, 2019

Giglio_A said:
Larry,

What does the catalog say the change gear set includes as a standard for a Cataract 37 and 47 headstocks? I would like to complete the set that I started with the purchase from you. Thanks

I put the change gear information into excel spreadsheets. Here are excerpts of the gear information from each one.

SCREWCUTTING IN THE HARDINGE CATARACT NO. 3 LATHE

GEAR CHART FOR USE WITH AN INCH SLIDE REST WITH 10 TPI LEADSCREW AND 40 TOOTH GEAR ON SPINDLE

ALL GEARS ARE 30 DP 14 1/2 DEG. PA. SET IS: 25 (2), 30, 35, 40, 45, 46, 50 (2), 55, 60, 65, 70, 75, 80, 90, 100 AND 127 TEETH

SCREWCUTTING IN THE HARDINGE CATARACT NO. 4 LATHE

GEAR CHART FOR USE WITH AN INCH SLIDE REST WITH 10 TPI LEADSCREW AND 60 TOOTH SPINDLE DRIVER GEAR

ALL GEARS ARE 30 DP 14 1/2 DEG. PA. SET IS: 25 (2), 30, 35, 46, 50 (2), 55, 60, 65, 70, 75, 80, 90, 100 AND 127 TEETH

SCREWCUTTING IN THE HARDINGE CATARACT NO. 5 LATHE
OR CATARACT NO. 4 LATHE WITH LEVER COLLET CLOSER
GEAR CHART FOR USE WITH AN INCH SLIDE REST WITH 10 TPI LEADSCREW AND 70 TOOTH SPINDLE DRIVER GEAR

ALL GEARS ARE 30 DP 14 1/2 DEG. PA. SET IS: 25 (2), 30, 35, 45, 46, 50 (2), 55, 60, 65, 70 (2), 75, 80, 90, 100, 105 AND 127 TEETH Note that the spindle gears were sized to fit the spindle, with smaller gears on smaller spindles. But I expect there would be no difficulty using larger count gears on the smaller spindles. Of course, the change gear charts depend upon the spindle gear. I had a later type Cataract bench mill power feed unit that only had a few gears with it, but they seemed to be in increments of 6 teeth instead of 5. I have never found a gear chart for the mill power feed unit.

Larry

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