700 series carriage lock

The carriage lock itself us usually a pretty simple piece to duplicate. All of the ones that I have actually seen were basically a short piece of steel flat bar with the center 70 percent or so milled about 1/16" thinner than the ends, And with a hole drilled and tapped in the center. If you can't buy a replacement but have access to a mill or milling attachment, the hardest part of the job will be figuring out what to do with the left-over material. If you are going to make it yourself, and are going to use a milling attachment, cut two pieces and drill and tap one of them to use as a temporary lock shoe while you are milling out the other one.
 
I don't have a mill. it could probably be made out of a piece of flat barbut I don't really understand why the tapped hole is put in on an angle? im thinking a piece of flat steel would work even though it doesn't have the valleys in the center.. think that's more art then anything
 
I think that the valley is there so the .lock isn't wearing the edge of the ways. It is easy enough to add that relief with a file though. As the the screw, if it is stripping out now, I wouldn't be comfortable with just a threading to the end. You would only gain two extra threads at the most.

In my mind, form follows function. The lathe is meant to be used. If you are concerned about appearance or not being able to use the OEM wrench, making a new screw shouldn't be that difficult, even without a mill. I would turn the head of the bolt to a diameter equal to the distance across the points of the square head (1.414 x the distance across the flats). Then I would file the flats. Clickspring has some great videos on working with a file. If your bull gear has index holes on the side, you can use the lathe to scribe guide lines 90º apart on the cylindrical head.

Fastenal sells square head set screws.
Set Screw.JPG
 
I think that the valley is there so the .lock isn't wearing the edge of the ways. It is easy enough to add that relief with a file though. As the the screw, if it is stripping out now, I wouldn't be comfortable with just a threading to the end. You would only gain two extra threads at the most.

In my mind, form follows function. The lathe is meant to be used. If you are concerned about appearance or not being able to use the OEM wrench, making a new screw shouldn't be that difficult, even without a mill. I would turn the head of the bolt to a diameter equal to the distance across the points of the square head (1.414 x the distance across the flats). Then I would file the flats. Clickspring has some great videos on working with a file. If your bull gear has index holes on the side, you can use the lathe to scribe guide lines 90º apart on the cylindrical head.

Fastenal sells square head set screws.
View attachment 308952

that would probably work...doesn't have the shoulder like the original but a washer would suffice... funny that Fastenal online is willing to sell but on the door of the business locally they have a sign that reads contractors only no private sales.... as far as making the plate part of it your right it could be done with a file or even a grinder... drilling the hole would be easy enough but too duplicate the odd angle back into the hole would be a bit tricky... who knows maybe thats why it failed. puling the threads on an angle would prbly load them in one area...?
 
hmm might have to do something like that ball handle... just did it on the qctp.. came out pretty good.... but back to the saddle lock... the longer bolt worked for a bit but seemed I was always having to tighten it a bit tighter... rest of the threads gave out in the little cast iron locking piece.. not sure what im gonna do with that.. its not just a matter of drilling it bigger and threading a bushing as the hole goes into that piece on a compound angle.. for some reason..


Have you called Logan to see if they have one?
 
the website shows the nut portion for 21.00 the bolt is out of stock.... not sure how up too date that site is tho...seems it hasn't changed in quite awhile... at 21.00 for a part that size I'll keep it as a last resort...
 
For $21 I could buy enough material to either make all the mistakes I needed to make before I present a completed part or to Learn There is Much more LEARNING NEEDED before trying again! Either way a Lesson Well WORTH $21 and the effort to try in my book.
 
well i set the drill press table to about 5 degrees and drilled the hole out to just under 9/16... then took a 3/8 coupler nut and turned it down to about the same size left a 1/8 shoulder on it and cut the rest off... then brazed it into the cast iron piece. not pretty but I have threads again... it does lock the carriage down some but not really super tight maybe I gotta use a longer wrench.. then again theres not a hell of a lot of bearing on that cast irion piece to the bottom of the ways...if you look at my first post you will see its only those 2 square patches that grab the ways...
 
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