At work we had a very similar situation. They took a short length of acme rod, trued it up in the lathe and trued up a center hole for a live center very carefully. Then after trueing up a longer length of rod, about a 3 or 4 inch length in a centering 6 jaw they put the nut half way on the long piece and about half on the shorter outboard length. The live center was forced against that piece and loaded up properly and it held the nut only on the threads. But they still only could take light cuts. A long process to get there but you can. Thank you for the video, well done for sure.
Who would have thought them nuts would be so bad Still better than having to make them using the leadscrew to clock the rod great idea I’ve never seen it done like that Thanks for the vid shame you don’t do more you do interesting stuff 👍👍👍👍
Another easy and simple way to fix the face run out is to take a chuck of the stud, slice off a couple threads long disc off it, drill and tap the end of the stud dialed in the lathe (or thread a stub if you don't have extra stud) and drill a bolt clearance hole through the disc, thread the nuts on most of the way thread the disc in a the nuts leaving enough to clamp without bottoming out, insert a bolt and torque it up. This makes it fast to clean up a hand full of them and if the nut comes loose it runs away from the tool, like you brought up, and just run an upside down tool in reverse for left hand threads. I can't even tell you how many off the shelf nuts I've had to re-machine the faces on, that's why a lot of the time my customers that are using them in equipment bolt ups (pumps/gear boxes that sort of a thing) have them made from scratch as they just don't want to mess with junky hardware on what can be a million dollar piece of equipment.
I think of all the suggestions I have received I like yours the best. Simple and easy to set up. Unfortunately I didn't have any acme thread left over. Now that I know how bad the nuts are if I have to do this job again I will order extra acme thread and do it the way you suggested. The fixture can then be put away and used again later. Thanks, Ken
I don't know if you have one, but a mag chuck would have been one way to face the second side relying only on the first face to be flat and square while getting a pretty secure hold. Upside down tool running the lathe backwards also wouldn't have been wrong, as you pointed out, for doing the first face.
To reduce the Sphincter Pucker Factor I would be inclined to put a tool in Upside Down and run the Spindle in Reverse. That I think will cause the nut to move away from the Tool and towards the Tail stock. Just my thoughts, Cheers from John, Australia.
I agree and I mentioned that in the video. However I had it set up this way already by the time that dawned on me and I was pretty confident that it would be ok with the light cuts I was taking. You are right though. Upside down tool and spindle in reverse would cause the nut to move away from the tool in the event of a jam. A much safer situation. Ken
@@hmw-ms3tx Thanks for your reply Ken. I did miss that part where you mentioned that, perhaps I let the Video run while I went to the Fridge to get another Beer. Cheers mate, John, Australia.
Interesting approaches mentioned in the other comments... I would have drilled a few inches of the end of the acme rod and tapped it for a 1" pipe plug, then (band saw) slotted the acme rod and used it like an expanding mandrel. Presuming of course you have a few extra inches of acme stock to work with. You could then turn both ends and the OD of the nut in one op. Just more advise you don't need after you finished the work :)
It's funny almost every suggestion I've received in the comments I thought about when trying to come up with a way to do this. The expanding acme thread crossed my mind but I didn't have any acme rod left over to be able to try it. I also thought of two pieces of acme rod one with a hole and the other with a spigot that would be a close fit in the hole. Hold the piece with the spigot in the chuck and get it dialed in, then screw the nut on it about half way, then screw the second acme rod with the hole into the nut until the spigot is buried in the hole. This piece of acme rod would have a centre hole in it that could be supported by the tailstock. Squeeze the whole assembly with the tailstock quill and the nut rides on the flanks of the threaded rods. All of these options were too much effort for the level of accuracy I needed. However, if I ever need to do a similar job with greater accuracy I now have many different possibilities to try. Thanks, Ken
Lock one against the other and face the end to the shaft with the live centre, repeat it then put the 2 faces together then turn the OD and leave the unfaced side on the out side of your fixture.
He explained why he didn't want to do that. In practice I wonder if it was that critical. I suspect your suggestion would have been "good enough" for the job it was to be used for.
@@stevewilliams2498 I looked at the first 5 mins of the vid with out watching it through so my work around is not tainted by the end result. it can't be super tied up as it is a bolt thread not a machine thread.
Instead of the spreader bar, you might be able to use a short acme plug. That should ensure all load is on the thread only. You would have the extra step of making the plug though
Hello Thomas. That was my first idea but it turned out I only had about 3/8" of acme threaded rod (length) left over and it wasn't long enough to make a plug. I had thought about threading one myself but decided to try the spreader bar first as it was much less work. In the end the spreader bar, while not perfect, gave acceptable results for this job. After I did this I realized it would probably have worked better if I used a three point spreader bar (three armed spider) as it would have spread the load more evenly. Ken
Hi. I am a new subscriber and enjoyed this video. I was following your logic up to the point (no pun) where you were exploring the run out on the threaded rod. You dismissed the ID of the nut for a location register for for good reason. However you checked the OD of the rod which may not have been machined either. I wondered if your ball stylus would have been near the thread pitch diameter down in the thread ?
That's a good point. It was a bit of an assumption on my part. I figured the threaded rod was made by rolling the threads rather than cutting them (they looked rolled, not cut). In a rolled thread (as far as I know) the entire thread profile (minor dia., pitch dia. and major dia.) are all rolled into the rod at once and should all run concentrically to each other. In the case of the nut it was obvious that it was a cut thread and with the same grit blast finish on the minor ID I didn't trust that it was concentric to the thread itself (i.e. pitch diameter). In theory I could have tried to dial in the major diameter of the nut (using the same technique I used on the threaded rod) as it was cut while the pitch diameter was being cut. However that would have been very awkward to reach and I would have been trying to establish two features (thread runout caused by eccentricity and thread runout caused by the nut being cocked in the chuck.) Not an easy thing to sort out when your indicator is constantly traveling to the left. Sometimes a guy has to make assumptions and hope for the best. In this case it worked out ok. Ken
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Enjoyed the discussion/demonstration/build….geeez, I was only watching a video and I had my foot on the brake pedal!!!
At work we had a very similar situation. They took a short length of acme rod, trued it up in the lathe and trued up a center hole for a live center very carefully. Then after trueing up a longer length of rod, about a 3 or 4 inch length in a centering 6 jaw they put the nut half way on the long piece and about half on the shorter outboard length. The live center was forced against that piece and loaded up properly and it held the nut only on the threads. But they still only could take light cuts. A long process to get there but you can. Thank you for the video, well done for sure.
Excellent video, thanks so much
Who would have thought them nuts would be so bad Still better than having to make them using the leadscrew to clock the rod great idea I’ve never seen it done like that Thanks for the vid shame you don’t do more you do interesting stuff 👍👍👍👍
21:25 "simply to - engage the lead screw"
so obvious, but so genius
Another easy and simple way to fix the face run out is to take a chuck of the stud, slice off a couple threads long disc off it, drill and tap the end of the stud dialed in the lathe (or thread a stub if you don't have extra stud) and drill a bolt clearance hole through the disc, thread the nuts on most of the way thread the disc in a the nuts leaving enough to clamp without bottoming out, insert a bolt and torque it up. This makes it fast to clean up a hand full of them and if the nut comes loose it runs away from the tool, like you brought up, and just run an upside down tool in reverse for left hand threads. I can't even tell you how many off the shelf nuts I've had to re-machine the faces on, that's why a lot of the time my customers that are using them in equipment bolt ups (pumps/gear boxes that sort of a thing) have them made from scratch as they just don't want to mess with junky hardware on what can be a million dollar piece of equipment.
I think of all the suggestions I have received I like yours the best. Simple and easy to set up. Unfortunately I didn't have any acme thread left over. Now that I know how bad the nuts are if I have to do this job again I will order extra acme thread and do it the way you suggested. The fixture can then be put away and used again later. Thanks, Ken
I don't know if you have one, but a mag chuck would have been one way to face the second side relying only on the first face to be flat and square while getting a pretty secure hold. Upside down tool running the lathe backwards also wouldn't have been wrong, as you pointed out, for doing the first face.
To reduce the Sphincter Pucker Factor I would be inclined to put a tool in Upside Down and run the Spindle in Reverse.
That I think will cause the nut to move away from the Tool and towards the Tail stock.
Just my thoughts, Cheers from John, Australia.
I agree and I mentioned that in the video. However I had it set up this way already by the time that dawned on me and I was pretty confident that it would be ok with the light cuts I was taking. You are right though. Upside down tool and spindle in reverse would cause the nut to move away from the tool in the event of a jam. A much safer situation. Ken
@@hmw-ms3tx Thanks for your reply Ken.
I did miss that part where you mentioned that, perhaps I let the Video run while I went to the Fridge to get another Beer. Cheers mate, John, Australia.
@@joandar1 Going to the fridge for another beer is a perfectly acceptable reason for missing part of a video.
Interesting approaches mentioned in the other comments... I would have drilled a few inches of the end of the acme rod and tapped it for a 1" pipe plug, then (band saw) slotted the acme rod and used it like an expanding mandrel. Presuming of course you have a few extra inches of acme stock to work with. You could then turn both ends and the OD of the nut in one op. Just more advise you don't need after you finished the work :)
It's funny almost every suggestion I've received in the comments I thought about when trying to come up with a way to do this. The expanding acme thread crossed my mind but I didn't have any acme rod left over to be able to try it. I also thought of two pieces of acme rod one with a hole and the other with a spigot that would be a close fit in the hole. Hold the piece with the spigot in the chuck and get it dialed in, then screw the nut on it about half way, then screw the second acme rod with the hole into the nut until the spigot is buried in the hole. This piece of acme rod would have a centre hole in it that could be supported by the tailstock. Squeeze the whole assembly with the tailstock quill and the nut rides on the flanks of the threaded rods. All of these options were too much effort for the level of accuracy I needed. However, if I ever need to do a similar job with greater accuracy I now have many different possibilities to try. Thanks, Ken
Lock one against the other and face the end to the shaft with the live centre, repeat it then put the 2 faces together then turn the OD and leave the unfaced side on the out side of your fixture.
He explained why he didn't want to do that.
In practice I wonder if it was that critical.
I suspect your suggestion would have been "good enough" for the job it was to be used for.
@@stevewilliams2498 I looked at the first 5 mins of the vid with out watching it through so my work around is not tainted by the end result. it can't be super tied up as it is a bolt thread not a machine thread.
Instead of the spreader bar, you might be able to use a short acme plug. That should ensure all load is on the thread only. You would have the extra step of making the plug though
Hello Thomas. That was my first idea but it turned out I only had about 3/8" of acme threaded rod (length) left over and it wasn't long enough to make a plug. I had thought about threading one myself but decided to try the spreader bar first as it was much less work. In the end the spreader bar, while not perfect, gave acceptable results for this job. After I did this I realized it would probably have worked better if I used a three point spreader bar (three armed spider) as it would have spread the load more evenly. Ken
@@hmw-ms3tx Yeah, my thought was a 3 point spreader bar with ball bearings as the contact points against the nut for the full kinematic approach.
Hi.
I am a new subscriber and enjoyed this video.
I was following your logic up to the point (no pun) where you were exploring the run out on the threaded rod.
You dismissed the ID of the nut for a location register for for good reason.
However you checked the OD of the rod which may not have been machined either.
I wondered if your ball stylus would have been near the thread pitch diameter down in the thread ?
That's a good point. It was a bit of an assumption on my part. I figured the threaded rod was made by rolling the threads rather than cutting them (they looked rolled, not cut). In a rolled thread (as far as I know) the entire thread profile (minor dia., pitch dia. and major dia.) are all rolled into the rod at once and should all run concentrically to each other. In the case of the nut it was obvious that it was a cut thread and with the same grit blast finish on the minor ID I didn't trust that it was concentric to the thread itself (i.e. pitch diameter). In theory I could have tried to dial in the major diameter of the nut (using the same technique I used on the threaded rod) as it was cut while the pitch diameter was being cut. However that would have been very awkward to reach and I would have been trying to establish two features (thread runout caused by eccentricity and thread runout caused by the nut being cocked in the chuck.) Not an easy thing to sort out when your indicator is constantly traveling to the left. Sometimes a guy has to make assumptions and hope for the best. In this case it worked out ok. Ken
👍😎👍