AMOLCO milling attachment

[HillclimberParticipant @hillclimber]

Just commissioning an Amolco milling attachment on my S7, and trying to understand parts of its operation.

Emerging diagonally from the powerhead casting is a prominent allen screw. By all appearances this should be a column lock. But the screw is not quite long enough to engage on the column, and if that is the intent it's a pretty clumsy lock as it is likely to result in damage to the column.

So two possibilities come to mind. Either there should be a soft pad below the screw, which allows pressure to bear on the column without marking it? Or I am completely wrong and it is to serve some other purpose?

Can anyone cast some light on this? And was there a ever a manual for these attachments that would release all its secrets?

Cheers, Colin

Edited By Neil Wyatt on 08/07/2018 22:48:25

[Neil LickfoldParticipant @neillickfold44316]

Google found this , http://www.lathes.co.uk/amolco/ Looks like the screw you are talking about is too short.

Neil L

Edited By Neil Wyatt on 08/07/2018 22:48:35

[BazParticipant @baz89810]

I would make a brass pad, if you fit a longer screw you will bruise the column, just my two pennyworth.

Edited By Neil Wyatt on 08/07/2018 22:48:41

[RobboParticipant @robbo]

Looks like there was probably a brass pad in yours and its got lost, as the screw is too short.

I checked the Amolco I've got hanging around and there is no pad, but the screw is long enough to lock on the column, and it also has had its end flattened and smoothed off before blackening, so looks like original. There are no visible marks on the column.

I would go for a shaped brass pad though.

Edited By Neil Wyatt on 08/07/2018 22:48:47

[Leszek DelagParticipant @leszekdelag40763]

[Leszek DelagParticipant @leszekdelag40763]

Hello all,

I recently bought an AMOLCO milling attachment online for my old Myford. It was in fact, in very poor shape all round on inspection after arrival, having had a very rough life and been poorly treated, but am gradually getting it back to running condition.

The spindle has an internal MT2 taper and an externally threaded nose. I would like to buy a collet set for it but am a bit confused by the many choices of size; ER20, ER25, ER32 etc.

The work I intend to do is to fine tolerances and I would be very grateful if anyone out there could offer some sound, practical advice and guidance to a beginner please..Also, is it possible to still buy the tapered bearings for this attachment as the existing ones are running very noisily.

With many thanks in advance..

[EmgeeParticipant @emgee]

Hi Leszek

If you can find out the bearing number you can search the bearing suppliers for replacements, they willno doubt be available, but don't buy the cheapest you see, keep with a known manufacturer of quality bearings.

If your spindle has provision for a drawbar then you could use MT2 collets, the disadvantage with these is they are for fixed sizes so you may need many different sizes, they do have the advantage of not taking up tool to table space so allow larger parts to be milled/drilled.

The ER collet chuck seems favourite these days as the collets hold a range of sizes so not so many are needed, before buying a collet chuck decide what is the largest dril/milling cutter/reamer you will want to use and get a chuck with the maximum size collet for the range.
ER11, ER16, ER20, ER25 all take different size ranges, ER25 goes to 16mm and is most likely as big as you will need on such a machine. All are available on MT2 shanks with drawbar facility.

Most makes will give fair accuracy but if you need minimum TIR then you may need to go up market with the holder and collets.

Emgee

typo edited

Edited By Emgee on 06/07/2018 00:31:55

[roy entwistleParticipant @royentwistle24699]

The Amolco milling attachment I seem to remember used Myford collets

Roy

[Howard LewisParticipant @howardlewis46836]

I would expect the external thread / register to be the same as the mandrel on the ML7

You can buy holders for ER collets with a 2MT shank. The drawbar thread used to be 3/8 BSW but more recent versions may have metric thread.

Your choice of ER size will depend up on what size cutters you intend to use. (For instance, ER20 will take upto 13mm shank. ER25 upto 16mm).

Based on my experience of a ML7 fitted with a Rodney attachment, don't expect to take big cuts, the lathe is not sufficiently rigid! 0.020" on steel seemed a pretty heavy cut on mine.

That should bring out of the woodwork, a lot of claims of deeper cuts without problems.

Good luck, and enjoy yourself!

Howard

[Leszek DelagParticipant @leszekdelag40763]

Firstly, thank you all very much indeed for your most informative replies…they are very much appreciated indeed!

I have been working on the Amolco attachment today, rewiring the motor electrics with correct and undamaged cable and replacing the existing cracked domestic light switch with an NVR switch. Have discovered that the nose thread is 1 1/8" BSW, the same as that on the Myford spindle. The internal thread is definitely MT2 but the spindle bore at the top is only 5/16" so I would imagine that I will have to make a custom drawbar for any collets I buy?

Many thanks Emgee for your observations re. an ER collet head taking up a lot of space..a very good point that as as everything is much more stable when the cutter is close to the spindle end. I already have a nice Albrecht keyless chuck with a No.2 Morse taper, which will hold drills from 3-13mm and feel that MT2 collets will be the best option as the biggest milling cutters I own have a 12mm shank. There is a German company on a well-known website offering a small set of precision MT2 collets from 4mm to 12mm for a fairly reasonable sum and they should cover most things that I intend to make.

Re. bearing replacement, point also taken about cheap bearings..I am looking at SKF ones at present but there is a question mark over the size..

There is a long way to go before the attachment will be usable.. I discovered today also, that the motor pulley block had been hammered on..! I eventually got it free with the aid of a custom 3-point puller, but the bore was so dreadfully scored up that I have had to bore it out in the 4-jaw on the lathe, sleeve it and rebore it out to size again. Have also removed a good few of the dents to the block and got it running true and concentric again.

I just don't understand how some folks can spend good money on nice machinery and then abuse it so much..

Will try and post a photo when it is finally operational again! Many thanks once again for your help.

Kind regards,

Leszek

[davebParticipant @daveb17630]

I had a Rodney attachment with my ML7, the cross slide wasn't rigid enough for milling, fitting a Super7 cross slide was a huge improvement. The attachment is intended to use the Myford patent 2MT collets, these are available used. Chucks use up a lot of space between the spindle nose and cross slide of which there isn't much to begin with. The prices being asked for used Rodney attachments is almost enough for a used milling machine – unless you really must have all the Myford attachments – that would probably be more useful. Machines with hammer marks were usually not paid for by the user!

[RobboParticipant @robbo]

Leszek

As has been said, the Amolco was designed to use Myford patent collets, with an external locking ring which fits on the nose thread.

If you want to use a drawbar you will find the the hole through the spindle is too small for most drawbars which are usually inserted through the top of the spindle. I have used an M8 thread drawbar in an Amolco by reducing the diameter of the part above the thread and inserting the drawbar up through the spindle nose before inserting the collet.

[Leszek DelagParticipant @leszekdelag40763]

By coincidence, I have just done this job!

Commonsense suggests that there should indeed be a soft pad in front of the screw-which is 3/8" x 20 BSF, by the way. Instead of just an socket head screw, I made mine as a ball-ended lever. The end of the screw was drilled out to 3/16" dia. x 0.2" deep and a 3/8" dia. piece of brass with a 3/16" dia. spigot on the end pressed in. The brass was turned down to 0.3" afterwards with a good chamfer on the front. The length of the brass pad was then adjusted until the lever locked on when about horizontal. It now pinches up quite nicely without faffing about with Allen keys and safe in the knowledge that you won't damage the column or get the brass pad stuck inside.

With regards..

Edited By Neil Wyatt on 08/07/2018 22:48:52

[Leszek DelagParticipant @leszekdelag40763]

Many thanks Robbo..I figured that this would be the way to go..

Having looked around, the cost of a set of genuine Myford collets-which have to be in very good condition for the work I intend to do-would probably cost more than I paid for the machine..if you could get them!!

I have ordered a set of MT2 collets from Germany. They cost £55.56 for the five, 4mm to 12mm, but seem to be good quality. They have an M10 thread so I am thinking of turning down a length of M10 studding where it has to pass through the top, then thread that end M8 or 5/16" and make a screw-on knurled hand wheel and spacer for the top.

It ought to do the job and wouldn't be to much bother to detach when not required.

Thanks again for the advice..

Leszek

Edited By Leszek Delag on 08/07/2018 22:48:02

[Neil WyattModerator @neilwyatt]

"Crossed threads" combined!

Neil

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