I need to make a small repair on my Franken Mill

[mike-sid]

I made a cut today and decided my mill's head was out of tram. No big deal...wrong. When I tried to loosen up the ram that holds my head, one of the levers just kept spinning.  Here is the result.







The shaft is threaded 3/8" x 24 tpi and is attached to the lever with a pin. The pin was sheared off and the screw shaft is bent at the top. Thinking back to the last time I adjusted the head, I noticed something was wrong but I had the head trued up and left it like that. Thinking way back, I think the shaft was bent getting it into my shop.
Time to get busy. Forgot to mention that I'm making a new shaft.

[PixMan]

Are you tooled up for threading the 3/8-24?

I don't recall if you and I ever went over the subject of threading tools.

[mike-sid]

We did go over it one time when we meet up for a beer. I have the Kennametal LSASR- 83 tool holder and I think you call it a "full forming" insert. I have a 16 ER 24 UNJ insert on hand. Does that sound right? I'm not so sure about the insert?

[the penguin]

Wouldn't be easier to just use a piece of hardened 3/8"-24, B-7 All-thread and pin the handle to it?

Would like me to send you a couple of pieces?

[mike-sid]

(01-18-2015, 11:03 AM)the penguin Wrote: Wouldn't be easier to just use a piece of hardened 3/8"-24, B-7 All-thread and pin the handle to it?

Would like me to send you a couple of pieces?

Thank you for the offer! But I want to make it myself. I need the practice. It is a very low tolerance part...even I can't mess it up as hard as I try

[Sunset Machine]

Looks simple enough, but what about the bottom half of the cotter? Those threads on the shaft looks pretty well trashed, the female component likely is too. Drill/tap it out to the next larger size?

[PixMan]

I'd be surprised if the threads are trashed because they stay threaded together unless you're taking it completely apart. It's probably just the rust making them look a little dodgy.

If the threads are junk I'd make all new parts! More work, but more fun and gratifying to do.

[mike-sid]

PixMan is correct. The threads are ok, the picture is not in the best of focus and the rust came out looking 10x worse than it is.

[mike-sid]

  My first attempt did not go well, but I learned not to take shortcuts even on easy work. I turned down  a .5" bar without supporting the other end. The first piece came out looking like wavy gravy . I threaded the part for practice. Here are some pictures of the first attempt.





 On the second try I used a live center. This worked great, nice finish and it cut nice and true. Here are a few pictures of the set up and part before and after threading.  I know some of you guys did this kind of work in high school, but I bought the lathe and Franken Mill and I'm learning  as I go.  I might add that I meet up with PixMan a couple of times and he showed me a lot. As a novice watching him set up and thread a new lead screw for my cross slide was truly inspirational.  





I still need to drill for the pin

[DaveH]

Nicely done Mike Looks good.
 
DaveH