MetalworkingFun Forum

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.

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.

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?

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?

(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

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?

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.

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.

  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

Nicely done Mike Looks good.
 
DaveH