Tool Post Milling/Drilling Attachment

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Tool Post Milling/Drilling Attachment

This topic has 16 replies, 10 voices, and was last updated 19 March 2019 at 16:43 by geoff walker 1.

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14 March 2019 at 14:36 #19271
Roderick Jenkins
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@roderickjenkins93242
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14 March 2019 at 14:36 #400358
Roderick Jenkins
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@roderickjenkins93242
Being the impatient soul that I am, I have conceived the need for an easily mountable tool that can be used for milling and drilling items held in the lathe headstock. I do this quite a lot with a vertical slide and 95% of the work is done at centre height. This is my attempt at a tool post mounted attachment:

The spindle is based around a pair of angular contact bearings and an ER11 straight shank spindle, both from ARC. The motor is a 200W 230V treadmill unit with speed control from ebay **LINK**

I'm waiting for a pulley cover to print at the moment.

Cheers,

Rod

Edit: I paid £44 for the motor – looks like he might be out of stock with speed controllers for the moment.

Edited By Roderick Jenkins on 14/03/2019 14:40:30
14 March 2019 at 19:41 #400391
John Rudd
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@johnrudd16576
Roderick,

Is the motor a universal type or permanent magnet? ( guess I really ought to ask the seller….)

Edited By John Rudd on 14/03/2019 19:42:23
14 March 2019 at 23:01 #400431
Roderick Jenkins
Participant
@roderickjenkins93242
Good question. This looks like the speed controller **LINK** It seems to run equally well in either direction by swapping the motor leads.
16 March 2019 at 16:23 #400679
Nick Wheeler
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@nickwheeler
I couldn't see the point of making a spindle driven by a separate motor, and didn't have any the bits to do so.

So £90 later, which included a set of ER11 collets and power supply, plus about an hour's worth of work, most of which was adapting the mini-lathe vertical slide to my WM250:

and

so it's height adjustable, and both the cross slide and vertical slide can be adjusted for all sorts of compound angles.
16 March 2019 at 19:33 #400702
Clive Foster
Participant
@clivefoster55965
Thats a very neat job Nicholas.

Usual reason for going the separate motor and spindle with belt drive route is to be sure the bearings are able to handle cutting loads. In particular most smaller size motors have bearing arrangements with fairly limited thrust load capability.

Think I'd look into using external thrust bearing to carry the loads.

Clive.
16 March 2019 at 19:47 #400706
Roderick Jenkins
Participant
@roderickjenkins93242
I'd considered a spindle like the one Nicholas used. My concern was that there might be insufficient torque to drive a 6mm drill through steel at 1000 or so rpm which is at the bottom end of the speed range for a 12000rpm spindle. I, too, had doubts about the robustness of the bearings. Hence my clumsy looking but workable solution. Happy to be proven wrong

Rod
16 March 2019 at 21:18 #400723
Nick Wheeler
Participant
@nickwheeler
Posted by Clive Foster on 16/03/2019 19:33:47:

Thats a very neat job Nicholas.

Usual reason for going the separate motor and spindle with belt drive route is to be sure the bearings are able to handle cutting loads. In particular most smaller size motors have bearing arrangements with fairly limited thrust load capability.

Think I'd look into using external thrust bearing to carry the loads.

The photos flatter it, it's not the prettiest thing when you see it in the metal. But by tapping 8 holes in something I already had, it gives a lot of adjustments over a large range of movements which should make it usable for the clock wheels I've not started for the last 3 years……

I've recently found a chunk of aluminium that would make another bracket for attaching to a QCTP tool holder. That would allow for the quick deployment of it for things like fluting knobs or crossdrilling. It's this sort of job that makes me wish I had bought a wedge type post, as integral Dixon holders are not something I want to make.
16 March 2019 at 22:53 #400733
Robert Atkinson 2
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@robertatkinson2
Posted by Roderick Jenkins on 14/03/2019 23:01:52:

Good question. This looks like the speed controller **LINK** It seems to run equally well in either direction by swapping the motor leads.

As it reverses by swapping the supply it is 99% certainly a permanent magnet DC motor. It looks like a PM. The odd 1% are the same as a "universal" (AC/DC) motor that has a full wave rectifier connected to either the field OR the armature winding. I've seen this on a couple of motors, it allows you to have a remote reverse switch with only two wires to the motor. It can be retrofitted to a standard universal motor. As you probably kinow to reverse a universal you have to swap just the field or armature.

Robert G8RPI.

Edited By Robert Atkinson 2 on 16/03/2019 22:54:31
16 March 2019 at 23:23 #400740
Roderick Jenkins
Participant
@roderickjenkins93242
Posted by Robert Atkinson 2 on 16/03/2019 22:53:26:

Posted by Roderick Jenkins on 14/03/2019 23:01:52:

Good question. This looks like the speed controller **LINK** It seems to run equally well in either direction by swapping the motor leads.

… As you probably kinow to reverse a universal you have to swap just the field or armature.

That's a very bold assumption Thanks for the information

Rod
17 March 2019 at 08:32 #400763
Ian S C
Participant
@iansc
Most tread mill motors are PM DC motors, they also make quite good alternators.

Ian S C
18 March 2019 at 07:36 #400934
Robert Atkinson 2
Participant
@robertatkinson2
Posted by Ian S C on 17/03/2019 08:32:17:

Most tread mill motors are PM DC motors, they also make quite good alternators.

Ian S C

A PM DC motor will never make an alternator of any kind. The commutator rectifies the rotor output so they produce DC. They don't even make good generators as you cannot control the output voltage for speed or load variations. I guess you could use a 230V one with a switchmode step down voltage regulator but its a bit of a weird approach.

Robert G8RPI.
18 March 2019 at 14:59 #401018
AdrianR
Participant
@adrianr18614
I was looking through MEW back issues and saw in #52 and #53 there is a description how to build the Quick Step tool post milling attachment. Might give you a hew ideas.
19 March 2019 at 11:49 #401191
lfoggy
Participant
@lfoggy
Nice job Roderick.

I am in the process of building a similar device based on an Arrand milling/drilling spindle. I just need to acquire a motor and was debating what to use. I was thinking of a 100 or 150w permanent magnet DC motor. I am not anticipating drilling more than around 4mm holes in steel or using small (>4mm) slot drills. Your 200w motor looks quite big but I guess you chose this because you are planning to drill bigger holes.

Have you found 200w to be OK for your application?
19 March 2019 at 14:26 #401218
Hollowpoint
Participant
@hollowpoint
Roderick

Ive been looking at that motor for a small wood turning lathe do you think it would have sufficient power? Also does it have holes for face mounting?
19 March 2019 at 16:25 #401234
Roderick Jenkins
Participant
@roderickjenkins93242
Guys,

I have successfully used a 120 Watt sewing machine motor with an Arrand spindle. 6mm drills are a bit of a struggle but it will drill 4mm with ease and drives a 6mm endmill OK providing the depth of cut is not too big. I was guided in my choice for the new system by the capacity of the ER11 collet chuck.

I couldn't really comment on use for a woodturning lathe, it depends on so much. For guidance, the top speed of the treadmill motor is 4000rpm so I would probably at least halve that speed with the pulleys for wood turning but, again, it depends…

HTH,

Rod
19 March 2019 at 16:43 #401242
geoff walker 1
Participant
@geoffwalker1
Hi Rod,

Nice set up that, I like what you have done.

You and Nick have also got me thinking. I have used this set up for years on my M type but now I have the seig mill I never use it.

With not too much trouble I guess I could retain the V/S, turn the potts through 90 degrees and mount the parvalux over the top.

We shall see, thanks to both for posting your work, very interesting.

Geoff
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