From: southbendlathe@yahoogroups.com on behalf of Dennis Turk [dennis.turk2@frontier.com] Sent: Saturday, December 04, 2010 1:53 PM To: southbendlathe@yahoogroups.com Subject: Re: [southbendlathe] Half Nuts  AAAAAAAAAA HAAAAAA; that is why I could not fine the 160 catalog number. I dont have an early N catalog though I do have a 1935 or 36 large lathe N catalog I have never seen one for the smaller lathes. If I had seen a picture of the lathe I would have known. Now I do have some N parts for a 9 inch and I will tell you that the N was a breed of cat all its own. The saddles will not interchange with a bed for an O R S and T lathes. The apron from an N will not bolt onto any of the other series saddles. The quick change gear box is different as the lead screw exits the box in a different place as required buy the apron gears. Also the end bracket for the lead screw is different and will not interchange. Just some observations. When I got these parts as I figured I could build an N series lathe with parts I have but I find that I cant without an N bed. Dennis T ----- Original Message ----- From: Steve Wells To: southbendlathe@yahoogroups.com Sent: Saturday, December 04, 2010 9:01 AM Subject: RE: [southbendlathe] Half Nuts The 160 was an “N” series 9 inch cast base under-drive. It still would be considered a “wide-bed” lathe. The N series had improved spindle hardness, the new double wall apron with multi disk wet clutch and a “push-pull” feed shifter. The three wide-bed series O, N, & R ran in production in the 30’s together. This N series ran until aprox 1937-38 being replaced by the T series which was the improved R series with Double wall apron, shifter and tapered gibs. The S series replaced all older wide-bed series in the next model year (39-40) with improved headstock oiling, super-finished spindle and all other features of the T series. Steve Wells ------------------------------------------------------------------------------ From: southbendlathe@yahoogroups.com [mailto:southbendlathe@yahoogroups.com] On Behalf Of Dennis Turk Sent: Friday, December 03, 2010 8:38 PM To: southbendlathe@yahoogroups.com Subject: Re: [southbendlathe] Half Nuts  Hi Dennis The PM is the Practical Machinist board. Been around for a long time. I am sort of active over on the South Bend site and lurk around the antique site also. I think someone gave you the link or the name of the fellow that is repairing half nuts. I just looked at my 1933 catalog and I dont find a 160 R in the 9 inch laths or the 11 inch. Are you sure you have the correct catalog number? If your lathe is a wide bed 9 inch tool room lathe with power cross feed then you could have two different half nuts. I have one new set on the shelf but unless I can identify your lathe I am not sure they will fit. Dennis ----- Original Message ----- From: Dennis Whitaker To: southbendlathe@yahoogroups.com Sent: Friday, December 03, 2010 5:22 PM Subject: Re: [southbendlathe] Half Nuts Good afternoon Dennis That is another place I screwed up, Jim suggested I practice a bit before i tried it, the way you guys explained it to me I thought I had it under control. Now I'll have to weld the hole up and get lots of practice. Dennis, I don't know an O from an A or B let alone junior or tool room, It's a 160R serial number 51,947. You guys looked it up before, I think it was Feb 1933 wide bed if I remember right, is this an O? I'd like to hear more these inserts, what is the PM board? Thanks Dennis T Dennis W --- On Fri, 12/3/10, Dennis Turk wrote: From: Dennis Turk Subject: Re: [southbendlathe] Half Nuts To: southbendlathe@yahoogroups.com Date: Friday, December 3, 2010, 1:54 PM Good Morning Dennis Well have to tell you my good man your half nuts are just about gone. And no there is no adjustment built into them. One of the guys on this forum or on the PM board is rebuilding half nuts with bronze inserts and what I have heard they work out really well. I do have a few sets on the shelf but not sure they would be much better than what you have. Understand on the old O series lathes be it a Jr. or a tool room model there are I think three different styles of half nuts and they do not interchange. I have a new set from a heavy ten and they do not fit the early O series aprons though the lead screw is the same. If you think about all the gears involved with cutting threads as well as the half nut you can see there is clearance from a little to a lot in ever joint between the spindle and the lead screw. You also have to take into account the end play in the lead screw itself. So when you move the saddle left to right with the hand wheel with the half nuts engaged you can also have end play in the lead screw as well as worn half nuts that you are feeling and seeing. One way guys make up for all this is to make sure you have moved far enough to the right for the start of the next pass. Then by placing a little pressure on the hand wheel as you start the spindle this will keep all the slack or clearance in all the gear train and half nuts and lead screw end play tight in one direction. Old time machinist will always keep a little pressure on the hand wheel so as to make sure everything is tight. On modern lathes you do this as the thread is being cut but you have to take your hand off the hand wheel before you try and pull the half nuts out at the end of the thread. On lathes with large course lead screws like the larger SB's and even bigger lathes if you put to much pressure on the hand wheel you can not pull the half nuts out they will be locked in. I have a number of lathes at my business and one here at home you have to operate this way when cutting threads. Its a hard lesson to learn as not letting up on the pressure on the hand wheel you will end up in a crash. Seen it many times. Threading is a learned art form Dennis. Its something a beginner needs to practice a lot before he commits to a real part he wants to keep. I have a friend that has a full five gallon bucket full of practice threads he cut before he attempted to cut a thread on a part he had to have a good thread on. I will say for a beginner he does a heck of a job threading but he has spent hours practicing. Dennis T ----- Original Message ----- From: Dennis Whitaker To: group Sent: Friday, December 03, 2010 2:23 AM Subject: [southbendlathe] Half Nuts Hello all I was trying to cut internal threads in a new chuck backing plate and totally screwed it up. It looks like the tool point moved left or right, randomly, not during the cut, but after I backed up and started to make another pass. The thread is 1 1/2" 8 tpi, I never released my half nuts, just released belt tension and rolled face plate backwards by hand as I don't have reverse. In trying to figure out what was wrong I noticed that with the half nuts engaged I could roll the carriage back and forth about 1/8", part of it is the lead screw, but most of it is the half nuts. Please tell me there is an adjustment for the half nuts! Thanks Dennis W __._,_.___ -- Web: http://groups.yahoo.com/group/southbendlathe/ More pix: http://groups.yahoo.com/group/SouthBendLathePix/ Newbie guide: http://groups.yahoo.com/group/SouthBendLathePix/ Files area FAQ: http://groups.yahoo.com/group/southbendlathe/files/SouthBendLatheFAQ.html Post: mailto:southbendlathe@yahoogroups.com Email Moderators: mailto:southbendlathe-owner@yahoogroups.com * * * * * Manage your subscription by sending a blank message as follows: Unsubscribe: southbendlathe-unsubscribe@yahoogroups.com Stop delivery: southbendlathe-nomail@yahoogroups.com Daily digest mode: southbendlathe-digest@yahoogroups.com Individual emails: southbendlathe-normal@yahoogroups.com Your email settings: Individual Email|Traditional Change settings via the Web (Yahoo! ID required) Change settings via email: Switch delivery to Daily Digest | Switch to Fully Featured Visit Your Group | Yahoo! Groups Terms of Use | Unsubscribe __,_._,___