ER40 collet chuck

I've got the boring complete and made the first light passes with a threading tool before calling it quits for the night. During the process, I discovered that the copy of the spindle nose I created a while back is slightly smaller than the actual spindle. At some point I should probably create a new one that is more accurate.
 
After many tests of unthreading the 3-jaw chuck and flipping the assembly to test the collet chuck the threads against the spindle, a good fit was finally achieved.


er40_2_004.jpg

From here on the rest of the machining will be done with it threaded onto the spindle. I have been considering options for attaching a spanner to the chuck body to assist in removal when it gets stuck. I am leaning toward drilling a couple holes for a pin spanner, any advice?

Before I can get to that though, I need to heat it up and remove the arbor which the 3-jaw chuck clamps to.
 
No offense intended but, that is some ugly raw material. There is no way my OCD would let me work on that internal thread without turning the OD round first. Chuck is coming out nice.
 
Pin spanner was my choice. A dedicated spanner means that you will know where it is when you need it.
PS your raw material looks fine to me.
 
Eventually I'll turn it round, but I didn't want to invest a lot of time cleaning it up only to make a mistake and have to start over (again). I don't mind ugly, a glance at some of my past girlfriends would easily confirm that I put more emphasis on other criteria before looks!

In my shop it's a guarantee that a 5 minute job will never take less than 10 minutes as I spend at least as much time figuring where I last left whatever tools I need. Sometimes I can measure the time it's been since I worked on a project by how far I have to dig to find what I need. :p
 
dtsh said:
In my shop it's a guarantee that a 5 minute job will never take less than 10 minutes as I spend at least as much time figuring where I last left whatever tools I need. Sometimes I can measure the time it's been since I worked on a project by how far I have to dig to find what I need. :p
Click to expand...

I can stretch some jobs out too. I'm so paranoid about leaving the key in the chuck, I often walk away with it in my hand to leave it sitting in random places around the shop. As far as your stock goes, my eyes would be drawn to the loping ob-round guaranteeing a lapse in concentration.
 
Firstram said:
I can stretch some jobs out too. I'm so paranoid about leaving the key in the chuck, I often walk away with it in my hand to leave it sitting in random places around the shop. As far as your stock goes, my eyes would be drawn to the loping ob-round guaranteeing a lapse in concentration.
Click to expand...

I have left the key in the chuck more than a few times; that's one advantage of this lathe, it starts up so slowly (relatively) that even when the chuck gets thrown directly at me it doesn't have enough velocity to do much more than startle and make me feel foolish.


A little more progress. I got the 8deg taper in and need to work on a smoother finish. I still can't seem to get a nice finish, I need to reexamine my cutting tools. That the internal taper is rough isn't surprising considering the boring tools I used has a rather fine point. The main body has been turned as well, so it's looking halfway reasonable now. When I get to it next, it will be time to start turning for the metric threads for the nut.
M50 x 1.5 (external)
Major: 49.968 49.732 (1.9672-1.9579)
Pitch: 48.994 48.894 (1.9289-1.9249)
Minor: 48.344 47.970 (1.9033-1.8885)


I ran my change gear script and compared it with the gears I'd calculated the first time I cut 1.5mm pitch threads and it came up the same, again, these are for my lathe with it's 12TPI leadscrew.

A=78, B=30, C=18, D=66, pitch=1.501 / 16.92tpi (where A is for the spindle, B/C are ganged, and D is on the leadscrew)

er40_2_005.jpg

er40_2_006.jpg
 
I managed to get the threading done sooner than expected. It ended up that I hadn't quite centered the stock and a flat spot remained, I consideed turning it down as small as the threads, but ended up deciding to mill the flat smooth and put another flat opposite it so that I can use it with a wrench. I may yet drill it to accept a spanner and have considered making a steel collar for it the same diameter as the nut to accept the same spanner. There's plenty of time to think about that and much more to be done yet.

Here's a view looking in the back at the spindle threads, there's still room to machine it down a bit, some of which will likely disappear as it gets closer to being done.
er40_2_009.jpg

er40_2_008.jpg

er40_2_007.jpg

I pretty happy with it thus far. A quick eyeball for runout shows there's some, but it's rough yet and there's room for improvement.
 
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