Clarkson Autolock S type small collet and chuck

[ricgstevens]

Hello from Melbourne. I’m currently mid-restoration of an Arboga U2508 mill-drill which has a Clarkson Autolock S type small collet system. I have the chuck but no collets.
I’ve been scouring the internet and the only collets I can find are used imperial sized collets. Metric ones are rare and virtually impossible to buy as a new set. I’m keen to get a set of metric collets (6,10,12,16mm). Most of the used collets are a little worse for wear too.
Can one of you experts point me to a hoarder of these collets?
Thanks in advance.
Richard.

 

[dutchgray]

They are easy enough to find in the UK, but then they would be, there's loads of Clarkson type collet chucks floating about.

But I would seriously consider not using the thing and going to an ER system for collets or sidelock end mill holders, provided your machine is on an "available" spindle taper and you haven't already got a massive stash of screw in end mills to use on the Clarkson.

 

[ricgstevens]

They are easy enough to find in the UK, but then they would be, there's loads of Clarkson type collet chucks floating about.

But I would seriously consider not using the thing and going to an ER system for collets or sidelock end mill holders, provided your machine is on an "available" spindle taper and you haven't already got a massive stash of screw in end mills to use on the Clarkson.

Your idea has crossed my mind. Luckily I’ve not invested any money into tooling yet. This is a new to me machine. The challenge I have with the system Arboga uses is the Clarkson Autolock chuck system which relies on a retaining washer slotted into either an MT2 or MT3 arbor held to the body of the drill via a threaded collar. Without this collar and washer , the entire arbor/chuck could fall out under lateral load.
I love the idea of using an ER32 collet system however I need to find a modified Morse Taper arbor which can take a retaining washer. Not sure if I’ve seen this anywhere yet. I’ve read elsewhere of someone considering having shoulders and slots machined into a standard Morse Taper arbor with an ER chuck. It was a discussion at the time and I’ve not sure if the chap ended up doing it.

 

[Peter S]

I have bought plenty of spare Autolock collets by keeping an eye on Trade Me here in NZ (like ebay).

The metric collets have a groove machined around the OD at the threaded end. The groove is just to help I.D. a metric collet.

Only buy them if they look as-new or vg condition. Butchers are able to ruin the hardened threads and collapse the split portion so it is difficult to screw a cutter in.

A Clarkson or Larcher are great cutter holders, it is impossible for the cutter to move. Impossible.

Unlike ER collet chucks.

However you can't use plain shank carbide cutters in your Clarkson.

Threaded end HSS milling cutters are still available in NZ, no problem.

 

[ricgstevens]

I bit the bullet earlier tonight and purchased what appears to be a lightly used arbor with 8 collets (4 imperial and 4 metric). Got it off a seller on eBay based in the uk. Shipping and Australian GST amounted to more than 50% of what the autolock items cost. Disgusting really. But what what am I supposed to do? Cry once I say. I really didn't want to shop around for bits and pieces.
I’ve also found a seller in the UK selling a range of threaded milling bits in 2, 3 and 4 flute in HSS and cobalt. Aiming to get in touch with them this week to get a range of milling bits.
I’m still at a loss on how to adapt/fix a face mill/shell mill to Clarkson Autolock arbor. I like the ones with replaceable tips. Looking for something no larger than 40mm in diameter to help me with light surfacing passes.

 

[dutchgray]

Pretty sure I had a look at that R8 autolock set this morning on ebay, a good one for sure, if I didn't already have one I hardly ever use on my Bridgeport I would have been tempted.
I guess you could sell on the R8 body to recover some of the cost.

I would think trying to hold even a small face mill on a 16mm screwed shank in an autolock holder wouldn't be very good. Would not be ridged enough, if it was a large size autolock with say a 32mm collet in I think you'd have more chance of it working.

You are really going to have to try and find actual tooling for the Arboga spindle or find standard tooling that you can modify to fit.

Clarkson did have a range of holders for facemills/ shellmills, in HSS and carbide insert cutter bodies, the "Dedlock" system, but those have been effectively obsolete for a long time and I don't think anyone makes cutters for them now, you still find used and some NOS.

 

[Peter S]

ricgstevens,

Good to hear you found some collets.

I wasn't sure what an Arboga U2508 mill-drill was, so did a quick search.

How about keeping the R8 collet chuck and start looking for a Bridgeport style turret mill

This video came up, he describes a method for fitting MT2 shank tooling to the Arboga MT3 system.

I think you would have to be careful with a face mill not to overload the morse taper and have it spin. (But I see you only intend to take light skim cuts).

I can't imagine it's much fun milling on a mill-drill. I recall having to use a tiny Modig mill, it would jump out of gear when it all got too much for the poor thing.

You might find fellow users on some of the home shop forums? I think there is an Aussie model engineer forum? Also HSM forum:

General - The Home Shop Machinist & Machinist's Workshop Magazine's BBS

This forum reserved for general machining discussion. Off topic threads are allowed, but will be closed if they go too far off track or become too numerous. Please add “OT” to the title of any off topic thread. Discussions on religion or politics are not allowed.

bbs.homeshopmachinist.net

 

[ricgstevens]

Pretty sure I had a look at that R8 autolock set this morning on ebay, a good one for sure, if I didn't already have one I hardly ever use on my Bridgeport I would have been tempted.
I guess you could sell on the R8 body to recover some of the cost.

I would think trying to hold even a small face mill on a 16mm screwed shank in an autolock holder wouldn't be very good. Would not be ridged enough, if it was a large size autolock with say a 32mm collet in I think you'd have more chance of it working.

You are really going to have to try and find actual tooling for the Arboga spindle or find standard tooling that you can modify to fit.

Clarkson did have a range of holders for facemills/ shellmills, in HSS and carbide insert cutter bodies, the "Dedlock" system, but those have been effectively obsolete for a long time and I don't think anyone makes cutters for them now, you still find used and some NOS.

I’m treating this Arboga refurbishment (rather than a full restoration) as a learning exercise. By comparison with other bigger milling machines mine is a really quite basic in terms of design although what drew me to it in the first place was its heavy build and overall good condition. I don’t believe this machine was ever abused earlier in its life. That said, face milling might be a tad over ambitious.