tag:blogger.com,1999:blog-1592992209402300549.post7457202360690410418..comments2024-03-28T08:06:43.198-04:00Comments on The Silicon Graybeard: Monday, MondaySiGraybeardhttp://www.blogger.com/profile/00280583031339062059noreply@blogger.comBlogger8125tag:blogger.com,1999:blog-1592992209402300549.post-35143482348338919862016-12-06T17:38:43.441-05:002016-12-06T17:38:43.441-05:00These are Kerk leadscrews, 4 tpi (.250 lead) dual ...These are Kerk leadscrews, 4 tpi (.250 lead) dual start threads. They're ~.442 across the tops of threads, which look like real acme profile, and are what Kerk calls their 7/16" or 11mm screws, in Kerkote, a permanently self-lubricating coating. <br /><br />In '07, I replaced the X/Y axis of my original Sherline mill with this setup. The X-axis gives 18 inches of travel and the Y axis is 12. The headstock doesn't reach to the middle of that; it's still only about 3". The real attraction was the ability to work on larger pieces, even if it took a few setups, like when I cut and drilled the front and back panels on my motor controller box. Another selling point was that they're supposed to be zero backlash and really fast on rapids. One out of two. They're NOT zero backlash, but they can do 90 IPM, and that's handy at times. The Sherline motor is 90W, 1/8HP, so no matter what else you do to it, it's going to be a light duty machine. <br /><br />I don't know if that 1/4-20 portion was machined onto the end by the vendor (A2ZCNC, who is now gone), or if the screws were ordered from Kerk that way. Looking at the current Kerk website (<a rel="nofollow">Haydon Kerk Motion Products</a>), they're very configurable. When things were looking a little bleak, I was considering emailing Kerk to see if I could get replacements. <br /><br />SiGraybeardhttps://www.blogger.com/profile/00280583031339062059noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-62417008540749772252016-12-06T15:35:55.004-05:002016-12-06T15:35:55.004-05:00Out of curiosity, what is the leadscrew diameter i...Out of curiosity, what is the leadscrew diameter itself? <br /><br /> It is a bit unusual the screw threads you are dealing with are National, I would have expected metric. ravennoreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-73606562901589345002016-12-06T13:18:23.997-05:002016-12-06T13:18:23.997-05:00That's strange, as Acme threads are what's...That's strange, as Acme threads are what's generally used on lad screws.....drjimhttps://www.blogger.com/profile/05647484115197408897noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-48606558397122350712016-12-06T12:47:06.536-05:002016-12-06T12:47:06.536-05:00The left end is kind of boogered, but it's nev...The left end is kind of boogered, but it's never used. The nut for this leadscrew is on the other end of the cross slide, and that end never gets closer than about 3 inches from being used. It doesn't even have to be threaded. <br /><br />As for the taper on the right end being useful, I'm with you. When I looked at that, I thought "this needs a key". OTOH, the other two axes still work without losing motion and they look just like this. <br /> <br />SiGraybeardhttps://www.blogger.com/profile/00280583031339062059noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-33867582435275258842016-12-06T12:17:08.555-05:002016-12-06T12:17:08.555-05:00The left end (shoulder) of the lead screw looks me...The left end (shoulder) of the lead screw looks messed up?<br /><br />If in fact the taper is the connection to the motor drive, any bad threads could keep it from being pulled up tight, and certainly a 5-40 is not the sort of thread to put much torque on...<br />ravennoreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-26715417660907526352016-12-06T09:31:01.266-05:002016-12-06T09:31:01.266-05:00They do look like Acme threads, but another pictur...They do look like Acme threads, but another picture I took shows that the threads aren't as square as they would be if they were Acme threads. They just got rolled over. <br /><br />One of my problems was that the pre-load nut didn't move properly on the screw threads. I needed a wrench when I should have been able to just spin the nut. A 1/4-20 stainless nut out of my parts bin didn't work right either. After running the die over it, both nuts turn freely. <br /><br />SiGraybeardhttps://www.blogger.com/profile/00280583031339062059noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-11694931113082691982016-12-06T00:14:07.554-05:002016-12-06T00:14:07.554-05:00I just looked at the pictures again, and I noticed...I just looked at the pictures again, and I noticed the top one is *not* a standard thread.<br /><br />Looks more like an Acme thread than any other.drjimhttps://www.blogger.com/profile/05647484115197408897noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-19982846375423548122016-12-05T21:53:58.309-05:002016-12-05T21:53:58.309-05:00I hate it when a vendor messes up an order.
And I...I hate it when a vendor messes up an order.<br /><br />And I think I'd start to hate the vendor if they did it twice on the same order!drjimhttps://www.blogger.com/profile/05647484115197408897noreply@blogger.com