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That Enco rod is utility grade 2G stock...I wouldn't use it on a machine tool. And you need single start.

What size do you need? I am going to order some good stuff in a few sizes so if my sizes match anyone else's I can split a rod. I only need a foot in each size but the minimum drop is 3 feet each size.

Greg

Hi Greg,
I assume you've thought of this but I'll ask anyway.
Have you priced a ball screw? I assume the price would be about half the price of my lathe but you never know.

Stuart

Hi Stuart...Yeah, I did think of a ballscrew but I have advice from trusted quarters that they aren't really appropriate for a manual machine owing to their tendency to creep or self-feed. Having said that I saw a King Rich cnc/manual turret mill the other day that had all ballscrews...it was silky smooth and the vendor (Standaco in Nunawading) said that it had no issues with climb cutting etc.

If I was going to go the ballscrew route I'd do my usual caper of waiting for the right thing to appear for a fire sale price (10% of retail)

If I was going to really upgrade my lathe I'd like a ballscrew z axis with a clutch at the headstock end and a variable speed drive with an ELS...dial-a-feed on the fly and instant threading at whatever pitch you want.

Then again lathes have been around for 150 years without such gizmos...and I do have that particularly good gear train on mine that lives in an oil bath so it'll likely last another hundred + years.

Greg

Hi GQ,

Funny, I also suggested a ball screw for Bryan's repair in the other thread, there seems to be a rash of cross slide repair threads lately.

The issue of backfeeding, should be simple enough to solve with a locking mechanism, something involving the gib would work.

I've had ball screws on the x axis of my mill for a while now, and have had no issues with backfeed.

Regards
Ray

That's interesting Ray...and encouraging. A ballscrew wouldn't work for me on my lathe I have decided as there is very little room for a nut under the cross slide; all of the ball nuts I've seen look pretty chunky. On the Z I am tempted.

The other project going right now is that Perrin mill which could use a ball screw on the X easily. In fact its going to get a stepper drive on at least that axis anyway, albeit hand wheel controlled.

Greg

Hi Ray,
I was going to suggest it myself the other day when I saw a price of up around $100 for a screw and nut, but they don't come in the same pitch so I left it.

Dave

Originally Posted by Greg Q

That Enco rod is utility grade 2G stock...I wouldn't use it on a machine tool. And you need single start.

What size do you need? I am going to order some good stuff in a few sizes so if my sizes match anyone else's I can split a rod. I only need a foot in each size but the minimum drop is 3 feet each size.

Greg

This is the description of what I an going to buy.


Acme Threaded Rods & Nuts; Type: Precision Acme Threaded Rod; Thread Size: 5/8-8; Thread Direction: Left Hand; Material: Alloy Steel; Length (Feet): 3; Number of Starts: 1 Thread Size: 5/8-8 Rotation: Left Hand Length Ft. (Feet): 3 Length (Inch): 36 Material: Alloy Steel Material Grade: B-7 Number Starts: 1 Manufacturer Part Number: 5/8-8LH131A
I am not up with grades but this would be hugely better than what I have at the moment. This lists the grade as B-7. Where does this fit in?

Cost is important but if anyone has a better solution I am all ears.

Dean

ENCO lists their acme threaded rod as grade 2C for accuracy...which is the lowest grade for a centralising thread form. They quote 0.009" per foot maximum accuracy. Surely it will have much less backlash than what you currently have, but I doubt that it'll be more accurate.

You can buy directly from their supplier, Keystone at similar prices. Keystone's website does mention precision products which are grade 3C or better.

Greg

Not planning on getting 5/8 X 8TPI I suppose. Guess you would be looking at metric sizes.

Dean

I am planning on imperial. All of the machines here are old. I don't feel like converting them now given the complexities involved.

I plan on getting 5/8" 8 tpi LH

and

1/2" 10 tpi LH

and bronze sleeve type nuts to suit that I can then insert into my old (custom shaped) bronze nuts.

Let me know if that interests you. If so I'll be happy to order whatever nut you want to go with your threaded rod. I imagine there's easily enough for three guys to share a 3' bar...just order as many nuts as required. In fact, I might just do that anyway and ebay a 1' kit with nut if no one else wants one right now.

Greg

Oh...My bud Mike and I will also order some larger sizes...I think 3/4 but I have to confirm that. There likely won't be any spare of that bar, but it is getting to the point that incremental shipping is cheap if you don't mind waiting for a sea container (8 weeks). Otherwise, I'm going to have it all FedEx'd by shipito.com, my preferred shipper for airfreight outside of economical postal limits, which this stuff will be. (since its not flat rate box sizes)



Greg

I would be more than happy to put my name down for a foot length of 5/8" 8 tpi LH and the nut you suggested bronze sleeve type nuts is what I want also. I will PM my email address. Thanks.

Dean

Next issue. My plan to fit the new section of thread is to bore out the remaining section to accept a length of the threaded rod which has been machined down to a suitable size. An interference fit would be best I think. I was then going to pin the two to prevent seperation. I have a 5/8 diam shaft at this point.

The Pin has to be surface level to allow the drive gear to fit over it (the one I have to make yet). I was going to drill right thru, say 1/8 inch, then drill bigger from each side for a short distance to form enlarged but surface level only heads. One end of pin could be pre machined. The whole then could be cleaned up with file etc.

I have thought about and rejected grubscrews. A spring pin could also be used.

Any ideas would be appreciated for discussion.

Dean

Originally Posted by Oldneweng

Any ideas would be appreciated for discussion.

Hi Dean,
Careful what you ask for

I dont see anything wrong with your idea. If you had the gear you could silver solder it but that will just give you more problems. One thing you could look into is a tapered brass pin like the ones used on lead screws. That would of course mean getting your hands on a tapered reamer. I'm guessing that is would give you a stronger joint but really, how strong does it need to be(I think knurling would be the hardest work a crosslide ever has to do(?). If would make it easier to get apart, but how likely is that?

Stuart

This seller may have what we need McMaster-Carr