What's new
What's new

New Parts for an Old Heavy 10

salesandinfo

Plastic
Joined
Mar 11, 2020
Location
Hyannis, MA Cape Cod
Hi,

I am looking to replace the bearings and lead screw on my South Bend Heavy 10, I’ve called around with no luck and was pointed to PM forum. Would anyone know where or who makes new parts for the Heavy 10?

Thank you in advance,
Jon
 
For the lead screw you really need to brush up on what makes an accurate enough ACME thread to be used as a lead screw. Unless South Bend themselves went to the trouble of installing the fairly specialized machine tools and metrology equipment to properly machine, grind etc and then verify the results, (and they may well have) then they were likely buying the ACME lead screws with blank un-machined ends from a specialty company and then doing the much simpler end machining themselves. There's a hell of a lot more to it than just slapping a shaft in any old lathe and machining lead screws by the thousands. EVERY feed screw will have measurable and what are called lead / lag pitch errors in them. Not only is it impossible to manufacturer "perfect" pitch feed screws, and even if it was, they start to wear less accurate the more there used.

For a bit of back round, Moore Tools in there book The Foundations of Mechanical Accuracy mention the efforts they went to trying for that perfection for use in there manual jig borers and grinders. They did manage to get those lead / lag errors down to low millionths of an inch, but that perfection was still impossible no matter how much money and effort they invested into the project.

You also won't find new blank ended lead screws using that search term simply because those specialty manufacturer's don't designate them as that. That industry calls them feed screws no matter where on a machine tool there being used. SKF, Nook etc all have websites selling exactly what your looking for "if" they happen to manufacturer the same direction of screw pitch, ACME thread diameter and TPI. The same is true for there ACME nut blanks as well. You'll also find there guaranteed tolerances for screw straightness and pitch accuracy. The price jumps a whole lot as that pitch accuracy and screw straightness gets better. They also offer custom machined ends to fit what you already have at a usually very high price. Most end users would simply order the screw and nut blanks and machine to fit there own machines themselves. As I said, there's a great deal more to this than just grabbing some ACME all thread off the shelf at a big box store that simply isn't even close to being good enough for that screw straightness and pitch accuracy. I simply don't know enough about those heavy 10's to judge if there lead screw diameters will fit within there spindle bore or not for machining the ends. If not? Then to even attempt this, you'll need access to a larger lathe and probably a half decent mill as well that can do this. Re-boring the original half nut assembly, splitting and machining the ACME nut blank to fit and then usually soldering the split nut into the original half nut assembly is then how it's usually done. If you don't have that machine tool access and the required skills to pull it off, then your going to have to pay someone who does.

Your bearing answers can be found doing a search since I'm sure that's been covered multiple times already.
 
For the lead screw you really need to brush up on what makes an accurate enough ACME thread to be used as a lead screw. Unless South Bend themselves went to the trouble of installing the fairly specialized machine tools and metrology equipment to properly machine, grind etc and then verify the results, (and they may well have) then they were likely buying the ACME lead screws with blank un-machined ends from a specialty company and then doing the much simpler end machining themselves. There's a hell of a lot more to it than just slapping a shaft in any old lathe and machining lead screws by the thousands. EVERY feed screw will have measurable and what are called lead / lag pitch errors in them. Not only is it impossible to manufacturer "perfect" pitch feed screws, and even if it was, they start to wear less accurate the more there used.

For a bit of back round, Moore Tools in there book The Foundations of Mechanical Accuracy mention the efforts they went to trying for that perfection for use in there manual jig borers and grinders. They did manage to get those lead / lag errors down to low millionths of an inch, but that perfection was still impossible no matter how much money and effort they invested into the project.

You also won't find new blank ended lead screws using that search term simply because those specialty manufacturer's don't designate them as that. That industry calls them feed screws no matter where on a machine tool there being used. SKF, Nook etc all have websites selling exactly what your looking for "if" they happen to manufacturer the same direction of screw pitch, ACME thread diameter and TPI. The same is true for there ACME nut blanks as well. You'll also find there guaranteed tolerances for screw straightness and pitch accuracy. The price jumps a whole lot as that pitch accuracy and screw straightness gets better. They also offer custom machined ends to fit what you already have at a usually very high price. Most end users would simply order the screw and nut blanks and machine to fit there own machines themselves. As I said, there's a great deal more to this than just grabbing some ACME all thread off the shelf at a big box store that simply isn't even close to being good enough for that screw straightness and pitch accuracy. I simply don't know enough about those heavy 10's to judge if there lead screw diameters will fit within there spindle bore or not for machining the ends. If not? Then to even attempt this, you'll need access to a larger lathe and probably a half decent mill as well that can do this. Re-boring the original half nut assembly, splitting and machining the ACME nut blank to fit and then usually soldering the split nut into the original half nut assembly is then how it's usually done. If you don't have that machine tool access and the required skills to pull it off, then your going to have to pay someone who does.

Your bearing answers can be found doing a search since I'm sure that's been covered multiple times already.
Thank you for your response, that helps a lot!
Respectfully, Jonathan
 
Hi,

I am looking to replace the bearings and lead screw on my South Bend Heavy 10, I’ve called around with no luck and was pointed to PM forum. Would anyone know where or who makes new parts for the Heavy 10?

Thank you in advance,
Jon
I S B Latheman does not have what you need you can buy accurate lead screw material in many pitches, left and right hand threads and also bronze and cast iron nuts that are oversize to machine to suit your needs. Green Bay Mfg. in Two Rivers Wisconsin has most anything you need. I made a cross feed screw for my Holbrook and it is dead accurate.
 
I S B Latheman does not have what you need you can buy accurate lead screw material in many pitches, left and right hand threads and also bronze and cast iron nuts that are oversize to machine to suit your needs. Green Bay Mfg. in Two Rivers Wisconsin has most anything you need. I made a cross feed screw for my Holbrook and it is dead accurate.
awesome, thank you!
 
I S B Latheman does not have what you need you can buy accurate lead screw material in many pitches, left and right hand threads and also bronze and cast iron nuts that are oversize to machine to suit your needs. Green Bay Mfg. in Two Rivers Wisconsin has most anything you need. I made a cross feed screw for my Holbrook and it is dead accurate.

I only saw rolled thread acme on their site?

FWIW, when i changed the bed under my 10K to a 54" length and needed a longer leadscrew, i, too used a rolled leadscrew from Roton. They won't tell you what the accuracy is; but it has been fine for everything i've threaded, and i don't avoid single point threading.

McMaster Carr will at least tell you what the accuracy is. Note that price almost quadruples for only about a 1/3 better accuracy and availability of options per thread and diameter decreases. (.009"/ ft, to .006"/ft). ("Precision acme" vs "Ultra- precision acme")


Nook offers rolled, milled, or ground thread.

Whatever you get, besides turning the ends and shrinking on the drive end from your old screw, DSCN0003.JPGDSCN0001.JPGDSCN0010.JPGDSCN0009.JPGyou'll need to mill a keyway in it.

smt
 








 
Back
Top