Need to value an ROK M-5S 240 LPI leadscrew

[electronrancher]

Hi,

I got a damaged leadscrew delivered with a M5 purchase, and seller wants to make an insurance claim. It's 240 LPI (with the clutch mechanism) which I was told is rare - I honestly don't know.

If there is a stable market for these items, could anyone estimate how much it would cost me to replace this with either a more standard 100-120ish, or a direct replacement of a 240LPI? Needs the clutch for M5S, though.

Thanks!

[ROLANDJAYS]

I tried to make a rekocut screw under 2 hours but it was too difficult. I value the screws at 350$ a piece because of everything that is involved. with or with out the gears. as far as I know im the only one making presto screws and it took a while to get those right. getting a rekocut screw made would be very expensive.
ok good luck.

[petermontg]

Hi

I can get screws for presto and rek o kut made.

Only in batch of 10 screws

€1000 per batch is €100 per screw.

Best
Peter

[electronrancher]

Thanks, guys. I was also thinking in the $300-400 range for this model, so that's reassuring.

Petermontg - when you say you can get screws made for 100 Euro, is that just cutting the thread, or does it include the one-way gear the M5S uses for manual advance? I took one apart, and while the guts were simple (sharpened flat spring), the material was an unusually hard copper strip whose construction and composition didn't seem trivial to duplicate. Lots of cursing getting that thing back together, let me tell ya!

[petermontg]

No I dont supply any gears just the screw am afraid.

[ROLANDJAYS]

I have looked into getting the gears made . There 100$ for the big and 50$ for the small, if you order a batch of ten .

[electronrancher]

FYI that small gear is pretty much identical to a common gear used in RC car racing - 36 tooth, 48 pitch. You'd need to mill it out to fit, but at least the base cost is less than $10 for that type of gear. But the big gear, and the clutch mechanism is not going to be trivial. I don't doubt it's a bit pricy.

[mratx]

Is the clutch/spiraling crank damaged, or just the leadscrew? I believe the gears for the clutch and crank are the same regardless of lpi for the leadscrew, so if they aren't damaged you would just need a new leadscrew/halfnut of some lpi. When I swapped out my leadscrew I just needed the screw and halfnut, I used the existing clutch/crank gears.

On a related topic, did Rek-o-Kut at some point add the spiraling crank, or was that an option available all the time? I had either an M5 or B5 that didn't have one, but the one I have now has one. Otherwise they seemed to be identical, but I have no idea what years they were made, the only catalog I have lists only the version with the crank.


Mark

[electronrancher]

Just the leadscrew is damaged, so yes - that might absolutely be an option.

I'm calling the lathe with the spiraling crank the M5S, although the badging is identical (Master Pro M5) to a non-crank M5. I got both types in a bulk lot, and it's baffling why any company would mark them identically when they are clearly different models. The 2-gear leadscrew is a bit longer than a basic one IIRC, and has special milling to accept the "clutch", or one-way mechanism or whatever it should be called. I didn't see any way to make a standard leadscrew into a clutch type other than at the machine shop which is not really an option for me.

So to (not) answer your question - I have no idea how those two models came about, but I too am curious.

[mratx]

The ones for the crank models are indeed longer, and I thought the ones with no crank did not have the small gear on the one end. I would think that you could convert a non crank version to a crank version if you could locate a matching gear, but you'd need to figure out how to mount the gear on the end, by tapping the leadscrew end or something similar. So if the small gear end on your 240 is intact, you could pull that (i think they're pressed on, but didn't remove my leadscrew from my lathe to check), and mount in on a non-crank leadscrew.