# Please Help Me Identify Two Missing Parts (logan 850 And Others)



## intjonmiller (Apr 15, 2016)

I just got my father's old Logan 850 reassembled last night (change and reverse gear assemblies have been disassembled for over a decade), except I'm missing three small parts. One, the 1/2-20 nut on the end of the leadscrew, I can grab at Ace. But the manual doesn't say what size the missing Woodruff key there is, and I don't know what the "collar" (LA-239 in the LA-42 bed assembly diagram) is or looks like exactly. The scan of the old manual isn't very clear. And I'm not confident in my ability to accurately measure the keyway. 

Would someone please provide either dimensions and description or a photo of the collar and a measurement of the key? I have several "extra" parts in the box, at least most of which are clearly from some other machine. 




The leadscrew turns easily by hand, and all the gears function as they should (albeit with one broken tooth on one of the reversing gears), I just need to make this final connection. 

Thank you!


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## intjonmiller (Apr 15, 2016)




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## John Hasler (Apr 15, 2016)

The key will be a stock size such as 1/8" or 3/16".    If you aren't sure you've measured it accurately buy one on either side of what you think it most likely is.  They're cheap even by my standards.  The hardware store where you get the nut will have a drawer full of them.


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## intjonmiller (Apr 15, 2016)

Yeah, I've bought them before (though not for a while). I just recall there being a rather large selection. I can size it on my surface grinder if I need to, but obviously buying the right one is ideal. Part of the issue is that I didn't think to size it while I was there and now I'm at work, wanting to pick it up on the way home...


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## John Hasler (Apr 15, 2016)

The Handbook has a table for "Key Size Versus Shaft Diameter".  What's the shaft size?


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## intjonmiller (Apr 15, 2016)

The diagram says "Lead Screw 46-5/8"".


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## wa5cab (Apr 15, 2016)

Intjon,

It won't help you with knowing which size to pick up before you go home but I just uploaded a chart of ANSI standard Woodruff key sizes and matching keyseat sizes to Downloads.  Look in Charts and Tables.  Should be at top of list.

First dimension to measure is width of the keyseat.  That eliminates about 80% of the list.


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## intjonmiller (Apr 15, 2016)

Awesome, thank you!


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## intjonmiller (Apr 15, 2016)

While we're on the subject, is there a favorite source for learning to use and manage these change gears and power feed? I mean I can search and find thousands of results on this site and others, but is there a recommended primer or anything? "Metal Lathe Change Gears for Dummies" kind of thing. Video is even better.


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## Dr Stan (Apr 16, 2016)

How to Run a Lathe by South Bend is a good start.  I believe Logan also published a similar book.  I'd check Amazon & FleaBay (EBay).


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## wa5cab (Apr 16, 2016)

Atlas Press Co. also published one called Manual of Lathe Operations and Machinists Tables (MOLO for short).  There are three versions of the South Bend publication in Downloads.  Two date to WW-I or the 1920's.  The third is 1966.  There aren't any scans of the Atlas MOLO in downloads.  It is technically still in print and available from the original publisher (now named Clausing).  So because the copyright situation isn't clear, we haven't uploaded any.  They turn up frequently on eBay.  

The down side to either publication is that all of the photos are of either Atlas or South Bend machines.  If you do decide to buy one of the MOLO's, get one published 1960 or later,  The only differences between in any given year between the Atlas and Craftsman versions are the front covers.  If you decide to purchase How To Run A Lathe, stick to the later ones as well.


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## Dr Stan (Apr 16, 2016)

lathe.com (Logan lathe) lists Running an engine lathe http://store.lathe.com/pl-50.html  However, the publisher (Lindsay) ceased operations last year, so I do not know if he has any in stock.  I just checked Amazon and Fred H. Colvin (the author of above book) has numerous books available.  Also if you do a search at Amazon using "how to run a lathe" you'll get 15 pages of books.  I suspect you will find what you need.


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## wa5cab (Apr 16, 2016)

"How To Run A Lathe" is the actual title of the SB publication, not a general subject.  "Running An Engine Lathe" might be another less well known possibility, especially if Logan recommends it.


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## Dr Stan (Apr 16, 2016)

wa5cab said:


> "How To Run A Lathe" is the actual title of the SB publication, not a general subject.  "Running An Engine Lathe" might be another less well known possibility, especially if Logan recommends it.



True, but tell that to the programmers at Amazon.


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