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Er40 collet chuck

140mower

140mower

Don
I'm pretty sure that I have shown the collet chuck I made for my South Bend 10k, well over the weekend I was talking to @JustaDB on the phone and mentioned that a collet chuck would be a great project for his new to him 9a. I dug through the pictures on this phone and realized that I was over half finished the thing when I got this phone. (I had a sad go of it in that time period where two phones committed suicide in a short period of time. Both jumped to their demise, probably took too many selfies for their liking.) Alas, some pictures are recreations, so if something doesn't seem right, it might not be.... If anyone has any ideas or sees a better way, jump in and let's see if we can get James into a little project. ;)
20230223_190325.jpg
 
For material, I used 4340 and was quite pleased with the way it machined and the finish. For this operation I have no pictures, but I put it in the three jaw and opened up a hole through it to just under the minor diameter of the er40 collet. From there, I measured the depth of the threaded sections of a few backplates and kinda took an average of those and bored for the minor diameter of the 1 1/2" 8tpi threads to that depth. This was my first time internal threading, so I was pretty nervous about it, but it was all for naught and they came out nice and my thread guage earned its keep. Next I took it over to the mill and put a couple wrench flats onto it. You could drill holes in it for a tommy bar as well, if milling isn't an option. (Although, one could remove the toolpost, leaving the tee nut and stud and clamp the chuck with a big washer and mill it on the lathe.)
20230223_190420.jpg

As you can see, I left my usual "makers mark" when the end mill came loose....:rolleyes:
 
Next I mounted it directly to the spindle to finish the machining. First thing was to clean up the outside as it was still covered in mill scale aside from the two flats. Now it starts looking like a tool. Next, I turned the major diameter of the metric thread, but decided that I wanted to bore the angle for the collet next, because if I screw this up, there's no point in threading the end.
20230223_190157.jpg

This is basically the set up I used to dial in my compound to match the collet. Ideally one would probably want to turn a section between centers and set the collet up on that for the best precision. Then it was just a matter of boring until I was satisfied with how deep the collet sat in the chuck. I don't recall having a specific number here, just went with my gut feeling.
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A little blueing in the chuck once in a while, testing the fit.
 
Lastly, was to try out those metric transposing gears I have been proudly holding onto waiting for a reason to use them in anger. Other than not being able to disengage the halfnuts, there was nothing special about cutting metric threads.
The nut, I purchased from Amazon, I think I paid about $15 for it.
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.... and that's kinda the bulk of it all. The last picture is of it mounted in the 4 jaw on my 13" lathe.
 
Why an er40? Well, when I bought my little mill, it came with a set of er40 collets, and I love being able to share my tooling across more than one machine, so er40 it was. :p
This was a great weekend project and for minimal cash outlay I have a very handy little tool that can also be used on my dividing head, or, when I get it going, the tool head on my tool and cutter grinder.
I'm still very much a beginner in this hobby, and I believe the more tooling that I make for myself not only makes the shop's capability greater, but my skills as a machinist and confidence level grows as well.
 
Nice Job!

I didn't see any mention of making the eccentric ring that pulls the collet out when tight. Did you just drop that?

Or are you just using the nut from the mill version?
 
140mower said:
I'm still very much a beginner in this hobby, and I believe the more tooling that I make for myself not only makes the shop's capability greater, but my skills as a machinist and confidence level grows as well.
Click to expand...
Some shops cannot make these types of holders in house anymore, depending on customer approvals. When are made to buy as part of the TE agreements and so on.

That certainly isn't something that a beginner in this hobby could pull off IMO. You deserve to give yourself much more credit than you do.
Nice work with the blue in !
 
I am totally encouraged by this! My only ER32 holding is via an MT3 holder, and that's just too long a spindle for my little indexing jig - I get too much deflection and wind up needing to support it really awkwardly.
I'll start a new ER32 spindle for it this weekend!
 
140mower said:
It's like eating any other elephant
..... One little bite at a time. ;)
Click to expand...
First off, thx for posting this. When I get there, it'll definitely be a great template.

Second, I'll need more tooling in order to make it happen: metric threading gears, boring bar/threading bar. And, of course, collets & a collet nut. With budget constraints... I do like the idea of the ER40's though.

Third, the threading doesn't worry me too much (naively?). It's the internal taper that causes me pause.
 
JustaDB said:
Third, the threading doesn't worry me too much (naively?). It's the internal taper that causes me pause.
Click to expand...
Just taking your time to adjust the compound until the indicator reads zero all the way across, is all that it comes down to. It's kinda finicky, but five minutes and you are done with that part, then you start at the front and start boring, using the compound slide until the collet sits in deep enough. Blue up the bore check it against the collet and if need be, make minor adjustments to the compound until you get full blueing transfer from bore to collet.
You can do this...... You only need to remind yourself of that once in a while.....:cool:
 
While we're all looking at this ER40 chuck...
Morse Taper reamers are very available - AliExpress will send me coarse and fine set MT3 for about $30.
Any idea where I can find a 16-degree reamer? That would let me precisely clean up an ER collet chuck.
 
PaulL said:
Any idea where I can find a 16-degree reamer? That would let me precisely clean up an ER collet chuck.
Click to expand...
Honestly, no, I don't. The finish came out pretty nicely with a fresh hone on the tool and a light finishing pass. Could always try grinding it with a tool post grinder..... Just one more side project away...:p
 
140mower said:
Just taking your time to adjust the compound until the indicator reads zero all the way across, is all that it comes down to
Click to expand...
Well, lookit you go! I did not understand why the dial indicator. So many tricks to learn. Thx!

I did pick up some 1/2" drill rod on the offside chance that I'd want to try making a boring bar. I have an S&D drill set that will take me up to 1" on the adapter. I've been grinding my HSS bits so far, haven't found that too much of an issue. So, looks like eBay for the metric threading gears & a couple practice runs at threading.
 
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