DIY Milling/Drilling Spindle

[James AlfordParticipant @jamesalford67616]

I plan, at some stage, to make a milling/drilling spindle to use in a vertical slide on my Flexispeed. My thoughts are to fabricate a suitable housing, with bearings, for one of these spindles and then run it with a sewing machine motor.

**LINK**

Does this sound like a sensible plan? I like the idea of the spindle as it gives the collet holder rather than fabricating a spindle with a screw-on chuck or similar.

Regards,

James.

[James AlfordParticipant @jamesalford67616]

[Jeff DaymanParticipant @jeffdayman43397]

In my opinion sewing machine motor may be too low on power for much milling with your spindle. Might be fine for drilling small dia holes though. I would look for the biggest motor that fits without being in the way too much. You can belt it in several steps to a more remote location if need be. JD

[Michael GilliganParticipant @michaelgilligan61133]

James,

You should find several relevant discussions in previous threads.

… Have a look at Roderick Jenkins' Album for starters.

MichaelG.

[James AlfordParticipant @jamesalford67616]

Thank you for the comments and suggestions.

James.

[John HinkleyParticipant @johnhinkley26699]

James,

Unless I have misunderstood your intentions, aren't you about to duplicate effort? If you intend to add a milling spindle to a vertical slide, surely that is just adding another link in the chain, so to speak. Mounting a cutter in a collet holder in the lathe headstock and holding the workpiece on the vertical slide will achieve the same result. Or am I missing something blindingly obvious? If you want some idea of what the finished article could look like, have a look at this:

The motor is about 90W and for scale the collet is ER25. (The extra pulleys – unmachined in this picture – are to provide alternative spindle speeds.) The motor that I purchased (new) cost a little over £20 inc postage and included a primitive three-step speed controller. Allegedly revs to 10,000 rpm! Spindle is from CTC and runs in ball bearings. Only thing to watch out for is the direction of rotation of the motor.

John

[James AlfordParticipant @jamesalford67616]

John,

Thank you for the details of your spindle.

You are not missing anything: I want to be able to use a mill in the headstock chuck to mill work on a vertical slide and have a separate spindle to mill and drill work held in the chuck.

James.

[James AlfordParticipant @jamesalford67616]

John,

Out of interest: do you find that the motor is powerful enough for light milling?

Regards,

James.

[Douglas JohnstonParticipant @douglasjohnston98463]

These spindles are remarkable value for money and similar ones I have bought have been very well made. They are an ideal basis for making a milling spindle or simple indexer.

Doug

[Roger HeadParticipant @rogerhead16992]

I can't see any spindles on the http://www.ctctools.biz/ site. Do you have a direct link please?

Roger

[John HaineParticipant @johnhaine32865]

I wonder if the spindle uses a "collet chuck" from CTC like this:

**LINK**

as the shaft and chuck which is then mounted in bearings? These are remarkably cheap and well made and a great basis for tooling.

[Roger HeadParticipant @rogerhead16992]

Mmmm… I've considered that path before, then I read the earlier posts and took them to imply that a complete mounted spindle was available. Oh well, …

Roger

[John HinkleyParticipant @johnhinkley26699]

Roger/John,

My mistake for using the incorrect terminology (again!). I should have written collet chuck, not spindle. Sorry for sending you on a wild goose chase. I should have explained that the spindle as a whole was home made.

James,

To be perfectly honest, I haven't used the spindle for milling, just for a few drilling operations, I use my mill for, well, milling. I imagine that it would be perfectly adequate for use with small diameter milling cutters or engraving, for example. It's never going to be able to rip great chunks out of stainless steel, though.

John

[Roger HeadParticipant @rogerhead16992]

" I should have explained that the spindle as a whole was home made."

In which case, 'Well Done', it looks to be a very neat job!

Roger

[John HaineParticipant @johnhaine32865]

There was an article in MEW some time back by Dick Stephen on making a new high speed head for an X3 mill based around IIRC an ER25 collet chuck of this pattern. Neil can probably advise which issue?

[CotswoldsPhilParticipant @cotswoldsphil]

Here is my cobbled together version of a tool-post spindle. It was driven for years by a flexible shaft from a remotely fixed 1/4hp motor (now driving my tool-grinding spindle) It can be used either way up and is always at centre height when mounted. It now has a 90 watt sewing machine motor (with basic speed controller) which is fine for drill spotting prior to transfer of the work to the drilling machine or perhaps engraving, but is not enough for milling, aside from the wrong type of taper mount chuck, it struggles with anything over 1/8 inch. Spindle speed is about 2000 rev based on the stated motor speed of 6000 revs.

I think Roderic Jenkin's suggested in another post that a 120 watt motor was the minimum.

It has also been mentioned to watch the direction of rotation. This motor was rotating in the wrong direction for my application, when received. It was a tricky/delicate, but not impossible job, to identify and swap the field coil connections inside the motor.

With regards to the usefulness of ready made ER20 straight shank chucks, I used one (from ARC – no connection) for an indexing head for my home made tool grinder which saved a lot of work. I lapped the shank and bore of the indexing head for a close running fit. Dry lubricated with graphite and it spins very freely without shake.

Phil

Edited By CotswoldsPhil on 02/01/2016 11:10:20

[John HaineParticipant @johnhaine32865]

Phil, I'm curious to know how the vertical bush which is bored out (presumably) for the tool post stud, is attached to the spindle housing – is it welded please?

[geoff walker 1Participant @geoffwalker1]

I have a 1/4 hp 1400 rpm parvalux which I use to power a potts milling attachment see photo.

It provides adequate power for end mills up 6mm used on familiar model engineering materials. The key for me is fine feeds, high speed and light depth of cut.

I have the potts mounted on the vertical slide and the power from the parvalux is via an overhead drive.

The potts is really robust design. I was lucky to acquire an old set of castings about two years ago. They were supplied to the original buyer by woking precision models in 1974 so it was best part of 40 years before I got them and made the attachment. As far as I know the castings are no longer available but if you are ever offered a set, buy them. Apart from usefulness of the attachment it's quite a challenge to make one.

hny to all geoff

[Roderick JenkinsParticipant @roderickjenkins93242]

Posted by geoff walker 1 on 02/01/2016 13:58:13:

The potts is really robust design. I was lucky to acquire an old set of castings about two years ago. They were supplied to the original buyer by woking precision models in 1974 so it was best part of 40 years before I got them and made the attachment. As far as I know the castings are no longer available but if you are ever offered a set, buy them. Apart from usefulness of the attachment it's quite a challenge to make one.

I'm sure Hemingway used to offer them and presumably have the patterns since they took over the Woking stuff. I think they stopped offering the Potts milling spindle when they introduced the Quick-Step; which is a pity since I don't really think they are rivals.

Rod

[CotswoldsPhilParticipant @cotswoldsphil]

Posted by John Haine on 02/01/2016 11:49:40:

Phil, I'm curious to know how the vertical bush which is bored out (presumably) for the tool post stud, is attached to the spindle housing – is it welded please?

Hello John.

I clamped the vertical block to the tool-post (as when in use) and scalloped out the seating for the spindle housing with a boring bar. It's all held together with 2 cap-head bolts (loctited) one each side of the tool-post hole. It's been like that for nearly 40 years and never moved.

The Potts is really robust design…

I agree.

I acquired a Potts milling attachment when a Super 7 came into my ownership about a year ago.

I remade the spindle to suit ER20 collets and managed to hang a 1/4hp small frame motor out the back or at the top as required. It has 3 speeds <>700, 1500 and 2840.

Phil

One day I'll get a post done first time!

Edited By CotswoldsPhil on 02/01/2016 15:59:51

[James AlfordParticipant @jamesalford67616]

Thank you for all of the ideas and comments. I have now ordered a couple of ER11 collet chucks on 4" parallel shanks to use as a base for a spindle and for a collet chuck for the headstock. I shall let you know how it goes, in due course.

I have not sortedout a motor yet, but there is plenty of time for that yet.

Regards,

James.

Edited By James Alford on 03/01/2016 09:36:27

[geoff walker 1Participant @geoffwalker1]

Hi phil

that looks like a neat set up you have on an original potts column type milling attachment.

G P Potts first introduced the column attachment in a two page article in vol 76 of M.E. magazine back in 1937.

It was originally made for use on the very early Drummond M type lathe having a two piece central locking bolt the top half of which had a threaded collar to screw down on to the top slide tool post stud.

I am currently making a column type potts so more pics of your attachment and drive would be of real interest to me.

No rush Phil when you have time, best regards geoff

[CotswoldsPhilParticipant @cotswoldsphil]

Hi Geoff,

Thanks for your interest.

I thought it easier to dismantle and let some pictures do the talking.

This protrusion is in the way to use the boss on the rear of the spindle housing to hang the motor from.

Adding a close fitting, collar secured with a couple of grub screws, solved the problem. I used the original draw-bar collet spindle as a pattern, extending the pulley end and added an ER20 collet chuck at the business end.

The 2 existing end-float adjusting nuts now sit inside the new collar.

A thick washer spaces over the remaining thread and provides clearance for the pulley.

The motor mounting is a length of 4 * 1/2 inch alloy bar with a split clamp at the spindle end and air-fits to pretty it up a bit. This 1/4 hp small frame motor is secured at the business end; others may require a bit more thought. Finally, a couple of 3 step pulleys to suit the belt which is 6mm round-thane? or similar.

The motor can be rotated to a convenient position as required by each set-up.

When I got the Potts attachment it was just a well made ornament with a single 1/4 inch collet; now it has a new life.

Regards

Phil

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