Fitting an ER 40 to an AL320G

[barkersegg]

Further to Eskimo's thread......

I wanted to fit an ER collet to my AL320 but keep the throughbore for longer lengths but all the suggestions made were to use a drawbar on it. Special thanks to Kev In Katherine for thinking outside the square and helping someone with limited experience to knock it up.....

Step 1, bought an ER40 collet holder and some 200sq x 20mm rolled plate - I had some 75mm round and then proceeded to cut the shaft off the holder and turn the plate round and fit it to the registration boss on the lathe back plate. It needs to be taken slow to get the correct fit but as the mountin screws are drilled through, it should align in the correct position. To ensure it goes on the same way each time, I stamped and numbered the holes. I then cut a fillet to weld the round onto the face of the backplate.
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[barkersegg]

Step 2 involved welding the housing (which a mate did for me) onto the adapter plate and then turning that round, boring it out to accomodate the holder and then drilling and tapping for two grub screws to lock it in. Those grub screws lock onto the milled flats on the collet holder to hold it in place.
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[Dave J]

Good work:2tsup: I need to make one myself one day. I don't do much collet work, but would be handy for some things.
Commercial ones are available if someone wants to go that way.
Chronos Ltd Lathe Type Collet Holders for ER Collets (http://www.chronos.ltd.uk/acatalog/Lathe_Type_Collet_Holders_for_ER_Collets.html)

Lathe collet chucks for metalworking lathes buy on line from Warco (http://www.warco.co.uk/Turning-Accessories-Lathe-Collet-Chucks-ER25-and-ER32-4291D2254D.aspx)

Tools4cheap LLC Online Machine Shop Tooling Store: Mill Tooling,ER Collets and Chucks (http://www.tools4cheap.net/products.php?cat=35)

Dave

[barkersegg]

The final step was to fit it up, face it off and then turn down to a more respectable shape - once it was all done, I measured the TIR at 8 thou.....I put that down to firstly my feeble attempts at machining my first project, secondly the grub screws are not a precise lock and lastly, there would undoubtedly be some play in the fit between the holder and the housing as it is not securely fitted aside from the grub screws........even to the best of my abilities someone more competent could reduce it even further
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This was a first attempt, it works and I have managed to work on long rods through the spindle bore as I intended without a drawbar.

The next Mk II model, I will attempt to reduce the TIR by boring a taper for the collets into some round fitted similarly mounted on an adapter plate........and then copying the thread for the locking nut....thereby not using a bought collet holder

All up cost of materials? not including the collet holder and set of collets, about $40 but priceless in terms of experience (thanks Kev....and see, not a drop of blood in any picture... :o.)

So Eskimo.........., it can be done (a lot better than me) but this is just one way I chose....hope it helps.....Lee

[barkersegg]

Dave, I looked at the commercial ones and spoke at length with Jeff Beck at Tool4Cheap but none were available in ER40 and those that were for other series, did not come with a correct registration to fit the AL320.....LMS was close, in terms of overall size but the freight would sting....then it would have to be adapted in any regard ......I thought if I had to cut a bought one, then holding it would be a bugga too in the 3 jaw so I might as well start from scratch and learn how to make it myself - at least if I stuffed it up then no great financial loss........

[Dave J]

Hi,
Don't get me wrong, I think you have done a good job and only posted the links for the lazy ones. LOL
One suggesting for getting less run out would be to set up a dremel or similar tool as a tool post grinder and take a light slim off the ER taper. Doing this will get you down in the low 10th's for run out.
Another way is you could machine a 20-25mm bar true in your 3 jaw to suit the largest collet you have, then put collet in your chuck and mount it on this bar backwards and face off the back of the plate to run true. That way when you turn it around and mount it, it will be running dead true with the collet taper so it will only need to be centered.

I have not had a look or used one of the commercial ones, but I doubt they would be dead true strait out of the box.

What type of registration does the AL320 have?

Dave

[.RC.]

I just made one out of a D1-6 backing plate on my lathe...

http://img.photobucket.com/albums/v606/OzRinger/th_colletchuck004-1.jpg (http://smg.photobucket.com/albums/v606/OzRinger/colletchuck004-1.jpg) http://img.photobucket.com/albums/v606/OzRinger/th_colletchuck007.jpg (http://smg.photobucket.com/albums/v606/OzRinger/colletchuck007.jpg) http://img.photobucket.com/albums/v606/OzRinger/th_colletchuck005.jpg (http://smg.photobucket.com/albums/v606/OzRinger/colletchuck005.jpg)

[Gavin Newman]

The AL320G has a fixed flange with three through holes that thread into the chuck or faceplate from the rear of the flange. It has a register that locates the chuck axially machined into the flange. The flange is integral with the spindle.

[Dave J]

Thanks Gavin.

Dave

[eskimo]

its a tad out of my league....
i will need to take night classes before I tackle something like that..
maybe one day I might have a go, but for now I might just get a collet chuck

[barkersegg]

Eskimo, we've all got to learn otherwise why bother at all??? :C .....this was my first project and like you, ummed and arred for months thinking along the same lines as maybe I'd overstretched my abilities etc..............but then $40 worth of metal, one or two medicinal frothies and a few hours lathe time is therapeutic enough for me......I'll have a go at MkII with sub micron TIR when the fridge recovers....:2tsup:

This Forum and the people on it are a greatly under utilised resource in your learning process.......it's a huge knowledge base ready to help as I found along the way, so suck it in bloke, and go for it.............don't forget ....lots of pics along the way so we can learn as well.........

[Dave J]

You have the right attitude and you are right in what your saying, there isn't a day that goes by that I don't learn a new technique or something else new on these type of forums.
If someones not confident, do a trial cut of a taper or a thread on a piece of scrap and when your happy with it do it on the job.

Have you thought about the idea above of mounting it backwards onto a machine true bar and facing the back of it? you may not have to ma MK2.
Here is a picture of the set up I was thinking of to do the facing, you should have minimum run out after doing this.

http://www.woodworkforums.com/attachment.php?attachmentid=152318&stc=1&d=1289108317
Dave

[barkersegg]

Thankyou Dave.............you're spot on of course - that's one way of truing it up .....especially like the drawings...very clever.......something else I'll need to learn......:?.

[eskimo]

Dave
Using your sketch on how to true it up ....
how would you get the bolt holes true?....wouldnt it be that if they are not true then the whole thing will be out of true even after doing what you propose?..remember I am still an apprentice in all of this stuff...hence my question..lol

[Dave J]

Hi Eskimo,
He said above that it isn't the bolt holes creating the 8 thou it's the grub screws so it's not much.
If after doing this you find the bolt holes are out slightly and you cant get it centered, you could open the holes up larger to let a bit of movement to get it to run true.

The facing could also be done after the two collet chuck parts are pressed/welded/screwed together, before mounting it onto a face plate and drilling holes. You would not get an interrupted cut this way from the drilled holes.

Dave

[barkersegg]

Eskimo,

As Dave mentioned...the TIR is caused by the grub screws engaging the milled flats on the collet holder...........there is no runout on the housing/back plate as they are turned in the lathe it is fitted too.......the way of mounting the thing up initially is to work on the boss registration in reverse........ie, do your measuring up for the boss etc and then cut it out - when you have it close enough, remove it, turn it around and mount it with the marked holes....it will involve trial and error to fit the registration.....once that is sitting true then everything else you cut or mount to it from then on will be true to your own lathe...there will be no runout from your holder (assuming none in your spindle etc)

I did not use the 3 jaw in making it so I simply measured the registration on the 3 jaw while it was off the lathe and cut the plate to that fit.......

MK11 for me will involve the same process as above but cutting the ER taper instead of boring a recess and fitting a bought one and then threading the housing to match the ER40 nut......

One project leads to another and I have since made a verticle milling slide attachment to go with this on the AL320......it's a modified bought one with full rotation as distinct from some methods of mounting them --- can post that process if you are interested............Lee

[eskimo]

yep please post