Needed: LeBlond Regal 13" Crossfeed nut (circa 1950 machine)

Need the subject part as mine is worn and broken.

You might be lucky LeBlond - LeBlond Ltd.

Be sure to have the mc serial # and as many details as possible when you call, it makes their life easier.


If you've not bought machine tool spares before, definitely BE SURE you are sitting down when you ask the price.

Yes,and LeBlonde will want to charge you for how many years the part has been in storage.

I do not think LeBlond supports Regal lathes that pre-date the "square head" Regal series. They have some information as to when a particular serial number lathe was built or shipped, but not much else. On the other hand, the heavier LeBlond lathes are supported with some parts and drawings, as I learned in dealings with LeBlond when I worked at NY Power Authority.

As noted by G.Wilson, LeBlond Ltd, if they have a cross feed nut on their shelves, will charge as if it were made of unobtainium. They are not so accomodating as Hendeyman or Logan, nor are there the huge numbers of new old stock (NOS) parts or good used parts available on ebay (or similar) as there are for South Bend or Logan lathes.

My own advice is:

1. Inspect the cross feed screw. Chances are if the nut is that worn and broken, the screw threads may well be knife-edged in areas seeing the most use.
Replacing a cross feed nut without addressing the cross feed screw is going to make things a little better, but not fix the root cause. A worn cross
feed screw will only wear a new nut, and things will start off as sloppy (or as nearly so) as they were prior to replacing the nut.

2. Write off any ideas of getting a new cross feed nut and screw from LeBlond, unless you have a side-entrance into Fort Knox's vault. I'd suggest you find a
local machinist (a kind of semi-hobbyist sort, or a retired machinist with a small shop) and ask about having a new nut and screw made. LeBlond likely had
a special set of taps (roughing and finishing) for cutting the threads in the cross feed nut. A good machinist with the time to grind a small boring bar
with a roughing tool and another for finishing the threads can cut that thread in a lathe. The nut can be made from a chunk of hard bronze bar stock.
I would go with something a little harder/stronger than ordinary 660 bearing bronze. Maybe an aluminum bronze. We used to re-make stem thread nuts for
large valves and sluice gate operators around the hydroelectric plants, and we used aluminum bronze to handle the higher thrust loads.

I'd remake the screw out of "Stressproof" or maybe 4140 or 4340 steel.

3. There is a shop that does make new feed screws and nuts for the South Bend Lathes. Not a big shop, and they seem like reasonable folks from what I've
read on their website. They may be able to make up a nut and feed screw for your Roundhead Regal lathe. I think they were named something like Miller
Machine Works, if my memory serves me right.

4. At the powerplant, years ago, we had a Southbend Heavy 10" lathe. The cross feed screw and nut were worn to the point the backlash was beyond belief.
Too many would-be "machinists" using the little lathe, plenty of government jobs happening during the night shifts. We ordered, being a power company
and having deep pockets, a new cross feed screw and nut from South Bend- who were in business at the time. As I recall, because that lathe had the
telescoping taper attachment, we spent a bit over 600 bucks on the cross feed screw and nut, and that is a good 25 years ago or more. Parts for
manual lathes no longer made are either non existant, or made of unobtainium if some new entity has taken over the rights to the old lathe manufacturer's
line of lathe. The name of the game is 'reverse engineering', and making parts or having them made locally. You may think a local machinist is charging
an arm, leg, half the family jewels and your firstborn son.... but figure the time needed to measure up the parts, grind the necessary form tools for
roughing and finishing the threads, and doing the actual work. Cutting Acme threads is slow going, a few thousandths at a pass on this kind of work-
the feed screw will want to spring in and away from the tool if you take too heavy a cut, and the boring bars will want to spring inward and downward
and away from the thread being cut when you go to chase the thread in the nut. It takes care and time. You may be surprised to find that the
local machinists can make the parts for a LOT less than LeBlond- if they even entertain the idea- can furnish them. This is "one off" work, not
the kind of thing being banged out by CNC machining centers. If you have access to a nice tight small screw cutting lathe, you can try making these
parts yourself. No better way to learn machine work than a job like this, IMO. Owning, restoring, reparing and working on old machine tools calls for
this kind of thing- reverse engineering, thinking, and designing/making parts with what's at hand.

If it's a standard size and pitch McMaster sells precision rod and nuts. Both the precision shafting and nuts are available in sizes 1/4"-16 through 2 1/2"-4. I made a new cross feed screw and nut assembly for a 1916 Seneca Falls Star lathe a couple years ago. The nut for my Star lathe was almost the exact same profile as the one for your LeBlond. The original nut and screw assembly were 7/16"-10. It was a proprietary size which is no longer available so I changed it to 1/2"-10.

Here's the nut I used:
McMaster-Carr

Here's the Acme rod:
McMaster-Carr

You better be sitting down when you price out the nut. The 1/2" size was nearly $120.00. The rod on the other hand was less than $15.00 for a 36" section. If you decide to go this route be sure to get PRECISION shafting and nut. The non precision nut and shaft are cheaper, but will result in play when assembled. With the precision assembly I have no trouble holding tolerances to .0005 on a hundred year old lathe.

The job was a fairly simple job that only took a couple hours. I measured the old nut then put the new one in the mill and cut it to size. Then I cut the threaded portion of old acme rod off the cross feed shaft. I bored a 1" deep .312 diameter hole in the remaining portion of the shaft. Then cut a section off the new 1/2"-10 rod an inch longer than the portion removed. I turned down the 1" long portion to .3115", and then slipped it into the remaining portion of the original shaft. I silver soldered the pieces together, and the new shaft was complete.

LeBlond says they do not have information on the lathe, based on an image sent to them, so getting parts will be difficult, not being able to specify the part number. Additionally, I do not look forward to paying an exorbitant price for the part. The nut and rod are left-hand thread. Rod will be easier to get as a stock item from an after market dealer, but the nut is the hard part. I may decide to cut it myself. Thank you.

Google the firm "Nook"- they make Right Hand & Left Hand modified Acme thread lead screws and nuts in various configurations. A few years back, I designed a fixture for some in-place turning of generator slip rings (on the generator rotors). We made a cross slide out of some "Durabar" stock, and used an old lathe compound. I ordered a LH lead screw and nut from Nook, and it worked out fine. There is another firm, "Roton", which also offers LH threaded lead screws and bronze nuts in a variety of shapes.

Both firms offer LH nuts for the lead screws in a plain cylindrical shape, material being a hard/high strength alloy bronze. Adapting one of those nuts to work on the LeBlond cross slide looks feasable. There may be enough meat in the body of those cylindrical nuts to allow the flat top surface and the "spigot" or "boss" that keys the nut to the cross slide to be turned from the nut body.

Here is the contact information for Miller Machine and Fabrication.

http://www.millermachineandfabrication.com/contactus.html

I was having a hard time getting their homepage to load but this page loaded and has their phone number.

I know that they make nuts and screws for Monarchs and South Bends. I bought a cross feed screw and nut from them a few years ago. It was very well made, fair price and arrived quickly. I'm sure they could make almost anything you need for you lathe as long as you can provide the dimensions. Might be best to just send them the old screw.

When dealing with LeBlond don't believe everything he says. Sent pics and number of our lathe, clearly an older 20" heavy duty. Got a prompt reply that it will actually swing 26" and weighs 24,000#'s. Tape measure and fork truck said otherwise. (22 1/2 actual and moved it with 8,000# fork truck)

If it were me I'd use my old lathe to make new parts for itself.

AlbertNakaji said:

Need the subject part as mine is worn and broken.
View attachment 178216

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Make your own... Should be able to do everything on a lathe and finish the outside surface with an angle grinder (if you don't have a mill).

I just made a replacement for my 15"; the original looked exactly like that. For the replacement I used 2 pre-made thread-mount ACME nuts that screw into the "housing" that I made. Utilizing 2 nuts gets you the ability to adjust the back-lash which is very handy because a lot of the pre-made nuts have a lot more clearance than the original leblond nuts had. As stated, you should also replace the ACME screw.

I will say you DEFINITELY want to stay away from Roton; their service is terrible and they will milk your pocket-book on the shipping charges.

AlbertNakaji said:

LeBlond says they do not have information on the lathe, based on an image sent to them, so getting parts will be difficult, not being able to specify the part number. Additionally, I do not look forward to paying an exorbitant price for the part. The nut and rod are left-hand thread. Rod will be easier to get as a stock item from an after market dealer, but the nut is the hard part. I may decide to cut it myself. Thank you.

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I don't know what happened to my earlier reply so I'll repost it. My cross feed shaft and nut were also left hand thread. I mistakenly linked to the right hand versions available from McMaster.

Acme Nut:
McMaster-Carr

Acme Threaded Shaft:
McMaster-Carr

They may seem expensive, but I've found they were well worth the money for both accuracy and ease of use. As a general statement almost all parts for any industrial quality machine are far more expensive than comparable parts for hobby machines. They are far more robust and will outlast those used in a hobby grade machine 10 to 1. They are used in machines expected to run 40 to 80 hours a week, 50 weeks a year, and last for decades.

I would venture to guess this is the first time the cross slide has been in need of repair in more than 65 years. Considering that a $150.00 repair seems inexpensive.

MSC has a replacement nut for about $120, similar, but not quite (and I don't know the dimensions). Also found some "Grey Iron Tower ACME Nuts" that looked similar too, but they were all too large (price was good). Nook makes high precision nuts and rod, but the price was way out of my park.

My thinking now is that if no one has a replacement, I'll make my own using 2 or 3 nuts. Should come out to way less than $100 with a little elbow grease.

I was also thinking about using a tap for the internal threads, but the appropriate one is about $80. For one-time use, that doesn't seem feasible. I could cut the internal threads in the lathe, but the cutting tool would be maybe $75. I'm not confident that I'd be able to grind the bit myself to get the proper fit (if it were something not as critical as a lead screw I wouldn't mind trying it). Again, the cost for a one-time use doesn't seem feasible.

One quote I pulled from the Home Shop Machinist was, "the Machinist Handbook recommends no more than 2 times engagement of thread...Meaning that if you have 5/8 dia. stem, your ACME threads need no more than 1 1/4" of length. There is no advantage to having more engagement than than,in fact it can actually be counterproductive". This suggests that my idea of using 3 nuts on the 1/2" thread would be counterproductive. Any thoughts on the reason for this?

It's 1/2"?? 8 or 10 tpi??

Iwananew10K's post had me scratching my head for a moment, as 8 thds/inch seemed initially like an odd number, as I tend to think of a micrometer dial reading in numbers like 0.200" per revolution. 10 tpi vs 8 tpi did get me thinking. My 13" LeBlond Roundhead Regal has the crossfeed micrometer dial graduated at 0.250" TOTAL cut per revolution of the screw. That being the case, ONE revolution of the crossfeed screw will actually move the crossfeed 0.125". 0.125" = 1/8", so the crossfeed screw on a 13" Roundhead Regal should be 8 threads per inch, Left Hand.

10 threads per inch will move the crossfeed in 0.100" per revolution of the screw, taking 0.200" as the actual cut. Using 10 threads/inch for a cross feed screw will mean the micrometer dial is going to be incorrect. Might work on a Southbend lathe, where, if I remember right, one revolution of the cross feed crank reads 0.200", or 0.100" "radially" or "off one side of the work".

Interesting little brain teaser, for sure.

Appears to be 1/2 x 10, but I'll measure the rod to be sure.

Using Nick's image, the nut on my machine is slightly different, as can be seen in the modifications on this image. I haven't measured the size of the cross section thread, but the ID is .438.

My "micrometer dial" is not calibrated. That being the case, there is no issue with the cross feed matching the dial.

Joe Michaels said:

Iwananew10K's post had me scratching my head for a moment, as 8 thds/inch seemed initially like an odd number, as I tend to think of a micrometer dial reading in numbers like 0.200" per revolution. 10 tpi vs 8 tpi did get me thinking. My 13" LeBlond Roundhead Regal has the crossfeed micrometer dial graduated at 0.250" TOTAL cut per revolution of the screw. That being the case, ONE revolution of the crossfeed screw will actually move the crossfeed 0.125". 0.125" = 1/8", so the crossfeed screw on a 13" Roundhead Regal should be 8 threads per inch, Left Hand.

10 threads per inch will move the crossfeed in 0.100" per revolution of the screw, taking 0.200" as the actual cut. Using 10 threads/inch for a cross feed screw will mean the micrometer dial is going to be incorrect. Might work on a Southbend lathe, where, if I remember right, one revolution of the cross feed crank reads 0.200", or 0.100" "radially" or "off one side of the work".

Interesting little brain teaser, for sure.

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Would the SB nut fit? I can use a 5/8 x 8 rod.
South Bend Lathe 13" Cross Slide Feed NUT PT65T1 | eBay

This has been mentioned on PM before.

"http://bbs.homeshopmachinist.net/threads/43645-Making-Acetal-leadscrew-nuts-the-easy-way"

McMaster has three different materials to select from as far as rods are concerned: 1018 carbon steel, heat treated 4140 alloy, and 304 SS. For the cross slide screw, which would be suitable?

projectnut said:

I don't know what happened to my earlier reply so I'll repost it. My cross feed shaft and nut were also left hand thread. I mistakenly linked to the right hand versions available from McMaster.

Acme Nut:
McMaster-Carr

Acme Threaded Shaft:
McMaster-Carr

They may seem expensive, but I've found they were well worth the money for both accuracy and ease of use. As a general statement almost all parts for any industrial quality machine are far more expensive than comparable parts for hobby machines. They are far more robust and will outlast those used in a hobby grade machine 10 to 1. They are used in machines expected to run 40 to 80 hours a week, 50 weeks a year, and last for decades.

I would venture to guess this is the first time the cross slide has been in need of repair in more than 65 years. Considering that a $150.00 repair seems inexpensive.

Click to expand...