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Thread: ER32 collet setup?
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24th Aug 2019, 06:48 PM #1
ER32 collet setup?
Hi folks, me again, the Serial Pest from the South.
I've had a search around but haven't found any direct answers on this, so all feedback is appreciated.
I have a Hercus 260ATM and a lot of the work I'll be doing will be on smaller stuff, often aluminium. I'd like to add a collet setup to my lathe, probably ER32.
The options open to me seem to include a collet chuck design built into an integral plate (I'd have to mount this on a Hercus threaded backing plate just as I'd do with a regular chuck), a collet chuck with MT4 taper threaded for a drawbar, or a collet chuck with plain MT4 taper, not threaded for a drawbar.
Seems to me the MT4 designs have the best chance of centering perfectly (correct me if I'm wrong) but...will I need to add a drawbar? I've a hunch that I probably will, as I'd hate to lean on the workpiece and find the taper spinning around and marking up the spindle bore.
All comments gratefully received.
Cheers,
Moz
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24th Aug 2019, 07:39 PM #2
Hi Moz,
Noted that the 260 has an MT4 taper in the spindle. My Myford is only MT2, so quite a bit smaller.
I have and use both ER25 and ER32 collet chucks, usually the ER32 in the spindle and the ER 25 in the tailstock.
Yes a drawbar is certainly required, as you say, you don't want the chuck coming loose under any circumstances.
I made a brass nut that fits into the open end of the spindle and has a shoulder that bears up against the outer diameter. Using a length of threaded bar, I loctited the brass nut onto the end and use that to ensure that the collet doesn't come loose. I do find that it takes very little force on the nut to secure the collet chuck firmly in the spindle. I use a soft faced hammer to tap the nut after loosening it a couple of turns to remove the chuck.
I had originally given thought to an ER40 on a threaded backing plate, but dismissed the idea because of the small through hole in the spindle. Only 9/16" inch ! However I've not really needed to pass anything through it other than the drawbar for the collet chuck.
Anything longer than three inches or thereabouts I support from the tailstock. It amazes me how much deflection you get when trying for bearing fits on spindles.
16-03-2019-001.JPG 16-03-2019-002.JPG
This is the nut that I made to fit the lathe bore.
16-03-2019-007.JPG 16-03-2019-003.JPG 16-03-2019-005.jpg 16-03-2019-004.JPG
Since I had made the nut to use an existing pin spanner and I couldn't find the one that I thought that I had, just couldn't find it. I've a sneaky idea that its got knocked off and ended up in the scrap. I had to improvise. This was easy to reach, so I drilled it and put a couple of pins in to use as a wrench.
16-03-2019-006.JPG
It works quite well. That threaded bar is 10 mm.
HTH.Best Regards:
Baron J.
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24th Aug 2019, 08:27 PM #3Philomath in training
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As John says, you would need a draw bar for the MT4 taper option. However, I think you are dismissing the integral plate option too quickly. If you buy something then yes, the accuracy is as good as you can set it up. However, if you make up a threaded mount for the Hercus, screw that onto the spindle and proceed to cut the external thread for the nut and an internal taper to seat the collet, everything should be as concentric as it can be. It won't be hardened, but for hobbyist use, it probably does not need to be. Nuts are not expensive.
Michael
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25th Aug 2019, 12:08 PM #4
Good thoughts both Baron and Michael, thank you.
At this stage I reckon that the drawbar option would be easier (for me) to set up. I'll definitely fit one of Mal's spindle thread protector collar thingamajigs though, don't like the thought of the spindle thread sitting out in the open.
Moz
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25th Aug 2019, 04:02 PM #5Most Valued Member
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Why not just get a screw on ER 32 collet chuck?
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25th Aug 2019, 06:59 PM #6
Hi Pipeclay, Guys,
Michael, was suggesting that Moz make one to suit his 260 spindle ! He may not be able to obtain one with the correct thread.
Moz, I made a spindle nose protector out of a piece of Nylon 60. It works brilliantly for me, I use a foam rubber ring between the chuck body and the protector in use. It stops any swarf from getting in there and causing problems.
28-11-2018-015.JPG 08-04-2019-005.jpg 13-01-2019-010.jpg
As you can see it just screws straight onto the nose of the spindle. Sorry I didn't take any pictures of making it. But I threaded it first and then turned the threads off so that it covered the register. You can see in the third picture that it screws right up, to completely cover it. Also in this picture you can see the foam ring between the chuck and protector face.
06-12-2018-005.JPG 06-12-2018-006.JPG
After turning it I found that it was very difficult to unscrew from the spindle. The slight oiliness made it hard, so I cut some flutes on the surface to give me some purchase to unscrew it. In hindsight I should have taken a few thou more off the threads, since the Nylon absorbs water and swells a fraction, in damp weather it gets a little tighter on the threads. But it does the job nicely.Best Regards:
Baron J.
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26th Aug 2019, 07:14 PM #7
Hey that'a pretty cool Baron, thanks for the pics.
It's got the wheels turning in my head.
(Stand by to see smoke coming from my ears...)
Moz
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27th Aug 2019, 08:24 PM #8Senior Member
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Pipeclay has the correct answer...why on earth would you not want a screw on one?
If youre making a drawbar setup, then youre already cutting threads, but you have more components to make.
If youre making a spindle thread protector, then youre ALREADY making a thread to suit the spindle nose.
The screw on chuck will have significantly more rigidity, given that its purchase on the spindle is at a much wider point. Youll have the luxuary of being able to put long stock into the chuck, which given youre planning to use it on a lathe spindle is very handy. The chances of it damaging the spindle taper is basically nil. The spindle nose threads are already protected. The threads are clearly suitable for mounting chucks on, otherwise hercus wouldnt have been doing that themselves.
Its not even a question for me, screw on chucks are plainly the best choice. The ONLY drawback is that you are not able to run the lathe in reverse while using that chuck. Its not been a problem for me in the near decade ive owned 260's and the near decade and a half Ive been teaching on them.
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27th Aug 2019, 08:54 PM #9
Scotty, guys;
I think you make a good point. Mind you, I'm new to this...until very recently I didn't even realise that a collet chuck that screws onto the spindle was on option - mostly, of course, because I didn't see any 'off the shelf' options that screw right onto the old Hercus spindle thread.
Now...yes, I am indeed starting to cut threads but not imperial threads yet. That's a long way down the track as I'll need extra gears for that. And the spindle protector I was considering was to be purchased (from Mal...) rather than made myself.
So tell me, is an off-the-shelf screw-on chuck available for the Hercus 260, or is this purely a 'make it yourself' option? If so, although I can see how it is the ideal solution, I fear it will be beyond both my budget (gears) and capabilities (threading/machining experience) for awhile.
Thanks again for your wisdom and patience, guys.
Moz
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27th Aug 2019, 10:26 PM #10Member
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Moz
I have the Er32 collet chuck I purchased from Pipeclay.
This describes how to recut to get better accuracy on your machine.
https://metalworkforums.com/f223/t20...s-260-9-hercus
Because the collet chuck screws home against the face on the spindle ( register I think Peter calls it ) there is a small variance between the machines.
I have 2 9" Hercus's and the one collet chuck doesn't provide the same accuracy on both machines.
Here is a link to where Peter was selling his collet chucks.
Simon
https://metalworkforums.com/f223/t20...2-collet-chuck
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27th Aug 2019, 10:30 PM #11Golden Member
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I made another one a few weeks ago. I cut 1-3/4" 8TPI thread on someone lathe with imperial leadscrew and done the rest on the hercus itself.
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27th Aug 2019, 10:54 PM #12Golden Member
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I am using 85% as reference so the minor diameter of the bore is 1.6120" for that thread...
I put the cutter upside down and cut in reverse.
20190827_213544.jpg
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27th Aug 2019, 11:09 PM #13
Simon, Jackaroo...thanks for the tips and advice!
Cheers,
Moz
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28th Aug 2019, 02:36 AM #14
Hi Moz,
Be very careful here ! The threads do not align the chuck to the spindle. Its the register that does that !
The threads only hold the chuck in place.
The register is the horizontal flat portion along with the flat face, immediately behind the threads. That is where the accuracy of the fitting is determined. Any damage to the surface of that portion will be detrimental. Absolute cleanliness of the register and the threads is vital.
Realistically the female part that fits onto the register should have a ground finish and virtually zero gap between the surfaces.
Get a bit of almost anything trapped there may mean that the chuck is hard or almost impossible to remove once its on.Best Regards:
Baron J.
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28th Aug 2019, 08:35 AM #15Senior Member
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I believe you can buy one from pipeclay, thats one option.
Option two is to buy the required gears to do the imperial threading. Id consider this option because it means youre going to finish the job still having the capacity to cut threads to mount things to your spindle nose. If you ever need a new backing plate for a chuck, or want to do some other bizzare attachment, then youre tooled up to do that.
Option three is to get someone else to do it. You could pay an engineering firm to do it. Alternatively, if youre not in a pants on fire rush, you can prep the part and mail it to me, ill thread it and mail it back. My lathes at school are imperial and Ive usually got one set up to do threading at any given time, so its not a huge job to put through.
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