Jump to content

Lathing long narrow objects

Titanium

By Titanium
in Tools & Equipment

 Share

Recommended Posts

Titanium Watch Enthusiast

Titanium

Posted
Posted

Lately I’ve been trying to make pins for a strap and to do this I need to lathe a bit of metal down to 1.3mm wide and it has to be 20mm long. To do this I place a live centre at the non-chuck end then slowly lathe the rod down. The problem I’m having is the diameter of each end can be up to 0.12mm thinner than the middle. I’m using an Emco Unimat 3 to do the work.

 

Is there a way to get better results or is it a difficult thing to do?

khunter WRT Addict

khunter

Posted
Posted

You're probably experiencing flex in the work piece, and without a steady rest on the back side of the work you'll get that. I would try turning shorter sections at a time, it might take longer but the results should be more uniform.

teegee Watch Enthusiast

teegee

Posted
Posted
6 hours ago, Titanium said:

.. each end can be up to 0.12mm thinner than the middle. I’m using an Emco Unimat 3 to do the work.

Such a thin and long piece will definitely flex with any significant tool pressure. You could try with an extremely sharp cutter (so not some carbide insert), or with a very sharp hand graver. Or try to stone/sand the 0.12 mm center error away..

measuretwice WRT Addict

measuretwice

Posted
Posted

There are many ways to come at this.  Easiest is to machine it in sections, like oldhippy suggests, have a little sticking out of the chuck, machine some, pull more out etc.  Sort of a manual Swiss lathe :) (with a swiss lathe tool stays still and the material advanced out of the chuck).

Does your lathe have collets or just the three jaw?  I don't think too many of those had collets so if its just the three jaw, carefully maintain the same radial position of the material - this will minimize the affect of scroll error as you reset the position.

You can get a less than a perfect finish this way but there is a neat toolmakers trick for that.  take two pieces of wood and glue some fine emery to them - roughing maybe 600 or 1000 grit, then 2000 grit.  Ideally flat little slips of hardwood, but two popsicle sticks might work (better if its harder).  pinch them over the revolving work, abrasive side to the work obviously, and bring to size.  Unlike holding the abrasive cloth by hand, the firm backing gives some control an makes it possible to end up with a reasonable good and smooth cylinder.  Make sure you protect the bed with paper towel, any abrasive paper gives off lots crap you don't want on the ways.  Now if you're ever called upon to make 1mm taper lap you know how lol

Titanium Watch Enthusiast

Titanium

Posted
  • Author
Posted
3 hours ago, measuretwice said:

ou can get a less than a perfect finish this way but there is a neat toolmakers trick for that.  take two pieces of wood and glue some fine emery to them - roughing maybe 600 or 1000 grit, then 2000 grit.  Ideally flat little slips of hardwood, but two popsicle sticks might work (better if its harder).  pinch them over the revolving work, abrasive side to the work obviously, and bring to size.  Unlike holding the abrasive cloth by hand, the firm backing gives some control an makes it possible to end up with a reasonable good and smooth cylinder.  Make sure you protect the bed with paper towel, any abrasive paper gives off lots crap you don't want on the ways.  Now if you're ever called upon to make 1mm taper lap you know how lol

This is a good tip. I guess I could put the wood in a vice and that should give me better control.

I have a weird ER chuck for the Unimat that attaches to the spindle but it does not normal ER16 collets properly. I think it's for ESX 16 collet which are apparently ever so slightly different. Today I ordered this collet chuck so I'm looking forward to using that. I'm still trying stuff. I'll report back if I find a good way of doing this.

9f3a1a3e-957a-4b13-88c8-a76e00d54e49_600

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

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.

×
 Share
Go to topic listing

  • Recently Browsing

    • No registered users viewing this page.

  • Topics

  • Posts

    • watchweasol
      Hello from the Netherlands

      By watchweasol · Posted

      Hello and welcome to the fo4um. Enjoy
    • clockboy
      Hello from the Netherlands

      By clockboy · Posted

      Welcome to the forum, enjoy.
    • JohnR725
      A lathe with indexing that won't break the bank?

      By JohnR725 · Posted

      You're asking a pretty broad question and you didn't specify the machine but yes it's simple especially if you have the right machine. The question has problems but I'll take it as it is. Is it really that simple yes especially if you have the right machine. So in the video below he's making a screw and yes it really is that simple but pay attention to the machine it is not simple at all probably wasn't cheap but it is small it will probably fit in your garage. Unfortunately wouldn't fit in my garage as it's far too cluttered up with things. In the video he talks about making a screw and pay attention to the machine. The machine has lots and lots and lots of cutters and lots of things to do lots of machining all-in-one machine conceivably one step after another all programmable. If you look at his channel lots of CNC's stuff and there are several other videos related to this machine. He goes to the factory where they talk about it and show all the other machines they make in Switzerland.  I did look up the specifications the machine I don't recall the price it's not going to cut wheels I think it has a maximum diameter around 11 mm basically it's really good for making small diameter watch parts. Then in one of the other videos he goes to a factory that used to make parts with waterpowered machinery been in business for 100 years and everything they now make is made with CNC machines including this one. What was interesting with the factory photo was that when they make some parts they can put them on a optical comparator comparator compares with whatever the reference is and the machine can be programmed to adjust its cutting to make sure everything is actually being made to specifications. Oh and then somewhere in all of this there was at least one picture of a balance staff can't have a CNC Swiss machine without making balance staffs.   It would be really nice if we had pictures of the machine. Then yes if you look at the page for wheel cutting you can enter parameters and it will generate a G code but he left out things? Notice he has a picture of a complete wheel but the G code isn't making a complete wheel it's only cutting the gear teeth I don't see whereas the program for crossing out the spokes? Typically when you see people cutting gears once the teeth are cut most the time the spokes are cut by hand. Occasionally someone will mill them out but typically not with the program which seems strange if you have CNC capability for instance one of my friends fill it used to design assembly line equipment or things to make things. So his hobby was to continue to make tools to make things like clocks. Very interesting and clever clocks but his true fund was making the machines to make the clocks. Then machine is not controlled by G code like we would typically find today as the stepping motor controller he has was made a long time ago and the individual controllers used a textbased program. So the company had a editor you could write a program to cause each the stepping motors to do something. So basically once you figure out how to cut a gear he would just change the parameters for different size gears so here's an example of a gear as you can see we have the teeth and the spokes. Then we have a picture the machine which sucks because it would've been so much nicer if I could've taken a picture when it was cutting a gears so we can see things better. Then yes there is a worm gear stepping motor indexing this is a mini lathe and the indexing is at the end of the lathe head hiding. The basic operation of this machine would be brass sheet not cut to a specific diameter size not even round mounted on the machine. Then it turns and a milling cutter will cut the diameter. Then the gear would be cut with a gear cutter. The same mill cutter for the diameter although conceivably change the size I don't know but basically the same milling for cutting the outer diameter would be used to cut the spokes. I really can't remember how he did the center hole but whatever it was was very precise.          
    • JerseyMo
      Does a lighter fluid trick actually work on vintage mechanical Timex watches?

      By JerseyMo · Posted

      Yeah I know the site and the creator of it.  the two video clips are good examples of the quicker method and a full tear down.  the quick method will work in many cases. But not always and not for all the different movements.  I strongly suggest to not bend the four tabs as was done in the first clip.  Instead there are three tabs that insert into the top plate, Much saver way as to not break a tab.
    • JseTay
      Lathe motor advice

      By JseTay · Posted

      I found a motor that is 3/4 hp and another that is 1.2hp. They come with speed controller. So I don’t think I would need a wiring diagram. But I sure appreciate you offering your help! Do you think 1.2 hp would be too much for a watchmaker’s lathe?
×
×
  • Create New...