Jump to content

My 1st milling/turning job...


Recommended Posts

...is a new cross-slide nut for the SIEG C0 lathe (copy of the Unimat 3). I suspect the original is made of brass, as even with good lubrication I have replaced two already due to all threading gone. For the third one I decided to take the matter into my own hands, bought a 16mm bar of SAE660 phosphor bronze, which supposedly is the most wear-resistant grade, and doubled the threaded lenght from 10 to 20mm. The part can be made with the lathe only, but since my "big mini" lathe has a milling column, I decided to give it a try.

 

DSC_0460_copy_800x600.jpg.34e26fd19d2f5a8140e020d445ed9626.jpg

16mm dia is perfectly sized for making the part, incidentally is also the biggest that can be fitted in an ER25 collet. I used a square block because I was thinking I would have rotated it in the vise, which of course wasn't necessary, neither it was to mill side faces at all, but I did it anyway for practice. In milling videos you hear all the time "just measure/move/divide with your DRO", well my machine doesn't have one anymore, as the crappy heads had rotten away also due to carelessness by the previous owner. However for a simple part like this just measuring and looking at the handle dials is enough.

 

DSC_0461_copy_800x600.jpg.9507e976e757315af6341ea4d34a039c.jpg

I then moved to the 4 jaws for turning and threading the top post. Centering the work was quite a struggle, as I scribed lines instead of indicating, thinking that would have saved time compared to using a dial indicator. Wrong, as I had to take awkward positions and too much eyeballing. Same story for the leadscrew hole. Note to myself: I need to make better "jaw pads" from copper.

 

DSC_0462_copy_800x600.jpg.5a1e097a073213c2a98ba5a7235b8d58.jpg

Original nut is on the right, threads are visible but don't hold at all. I think I managed to be well within 0.05mm for all the sizes, but made some small mistakes and still have room for improving. The nut works nicely and is well aligned as long the cross-slide bolt is not tightened too much, in hindsight I should have left the post a bit taller for that adjustment, but will use a small washer for the purpose.

 

DSC_0465_copy_800x600.jpg.75a82a759017f9e42c0569c10daac64f.jpg

Last picture is of the new quick change tool post that I bought for the occasion of having the baby lathe working again. Specific for the type, not too expensive and well made by Soba in India, it was something long overdue.

  • Like 5
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.



  • Recently Browsing

    • No registered users viewing this page.
  • Topics

  • Posts

    • although not in this case.  It was the Lugano Convention and its deficiencies that allowed a Swiss court decision in the first place.  This isnt really a Brexit issue at all.  A decision that affects both the EU and the UK should never have been heard in Switzerland. I bet the authorised service centres in the UK are pretty pleased.  It's a massive shame, though; I believe watch owners should be able to choose to have their watch serviced by whoever they trust.
    • Hi guys I think that old hippy is correct, it opens the gates for china to manufacture aftermarket spare parts. considering that they already do work on behalf of the Swiss I guess this decision gives the a little more legitimacy to tool up and I am sure they will take advantage of the situation either with or without the blessing of the Swiss watch industry  Having read about the protectionist machinations of the Swiss in the history of Europe they were the only ones to get fat at everybody else’s expense. I think the outcome could have been guessed at but ,  fair play to Cousins UK for standing up to them.  Now the question,  will everybody boycott Swiss watches and Swatch, no way they will still fill their coffers.  Me I stick with the Japanese once renowned for cheap shitty watches who came good through industrial effort and don’t for get the Russians that most dismiss as low grade crap. Wouldn’t buy a swatch product ever how about you all.? a
    • Hold the crown when in winding position, move the click away from the crown wheel, and then while holding the crown let it slowly unwind. I recollect that you must remove the automatic device bridge first, but maybe I'm wrong. You can first try without removing the automatic device bridge.
    • nevenbekriev- You nailed it with your description of me and my reaction when the clock started ticking again. I am a newbie.  I love the sound and idea of mechanical clocks but the idea of owning one and trying to keep them running has never appealed to me. My wife bought this one and an antique German wall clock.  When I looked into having someone repair them for me, the universal response was "it's really expensive to work on them, you should just replace the movement". So, I had nothing to lose, I started researching them and opened them up. The wife is happy because she hears the sound of the clocks again. But I have gone down the "accuracy" rabbit hole. In the vertical position, the balance wheel was not floating. It was sitting on the bottom of the frame. I adjusted the lower spring collet and got it floating. It easily passed the 270 degree 3 to 5 minute oscillation test. It took 8 minutes for the wheel to completely stop moving.  I put it the unit back in the movement and checked the safety pin. It does not touch the safety roller anywhere in +/-270 degrees rotation from neutral position. But the amplitude of the rotation with the spring fully wound is weak based on what you are saying. It rotates +/-90 degrees from the neutral position.  No, I did not take the movement completely apart.  That seemed way outside my skill set at the time. There is a reason I became an electrical engineer and not a mechanical engineer. I am much more comfortable with moving electrons than tiny moving metal parts. Will I do it in the long run? Anything can happen. I don't seem to be able to let it go.
×
×
  • Create New...