Author Topic: Toolpost Drilling Attachment for my Cowells  (Read 1827 times)

Offline andycarlson

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Toolpost Drilling Attachment for my Cowells
« on: December 08, 2019, 11:54:33 AM »
Hi all,

Thought I would share this - it's something I've wanted to do for some time - ever since seeing YouTube vids of toolpost drilling attachments on bigger lathes. The snag was always how to come up with something that would actually fit onto the little Cowells toolpost.

Here is what I came up with. It's not brilliant because I've tried to cut as many corners as possible. I will probably change it some more when I think of a better design but it does seem to be getting the job done, although it is taking rather longer than I had hoped.

The only small drill holder that I could find was the business end of an old flexible drive on which the cable had snapped in the middle (it did see a lot of use). Pulling this apart revealed a 3/32 steel shaft with the collet holder secured by an Allen screw.

The basic thing is a piece of 3/8 by 5/8 steel bar drilled through 1/8 lengthways. I made a couple of flanged bearing bushes for the shaft to run in - these are a push fit into the 1/8 hole.

I turned a point on another bit of 3/32 silver steel and hardened this to work as a scriber/centre punch.

The whole thing is driven by a 12V mini drill via the remains of the flexible drive cable which runs in a cut down length of its original plastic sleeve.

Dividing is done using the 64T gear marked up with a pen. An bigger washer under one of the idler gears effectively locks it into place and some more marker pen shows me where it needs to line up with the 64T gear.

It works but the main issue is that it lacks a proper place to grip it and apply pressure to the drill. I'm holding the end of the flexi drive sleeve but the bearing area gets pretty warm after drilling for a minute or so.

I'd be interested to know if anyone else has come up with a way to make a toolpost drilling attachment for the Cowells or something similarly small.

Online Jo

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Re: Toolpost Drilling Attachment for my Cowells
« Reply #1 on: December 08, 2019, 12:21:39 PM »
 8) Have you considered using a couple of hard disc drive bearings to support the shaft?

I haven't got a toolpost drilling attachment for my Cowells "Little C"


Jo
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Offline andycarlson

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Re: Toolpost Drilling Attachment for my Cowells
« Reply #2 on: December 08, 2019, 12:38:38 PM »
8) Have you considered using a couple of hard disc drive bearings to support the shaft?

I can't say that I've ever taken a hard drive apart - I tend to hoard them on the basis that they might have the only copy of some incredibly useful thing.

But yes, making some sort of 'handle' for the tail end incorporating a proper bearing (or two) is definitely under consideration... unless someone else here posts something that might inspire me to go down a competely different route than using the remains of the flexi drive.

Oh, and I forgot to mention earlier - there is 2mm of packing under the toolpost to bring the thing up to centre height.

Regards, Andy

Offline Dan Rowe

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Re: Toolpost Drilling Attachment for my Cowells
« Reply #3 on: December 08, 2019, 02:10:05 PM »
Andy,
I have been searching for watchmakers lathe attachments for several years now and I have never seen a drilling attachment for the tool post. The usual method is to use a vertical slide with a spindle that can be set at any angle and takes WW collets.

I did smile when I saw the markings on the 64 tooth gear, I did the same thing when I cut a 5mm quad lead screw and nut with my Cowells.

Cheers Dan
ShaylocoDan

Offline andycarlson

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Re: Toolpost Drilling Attachment for my Cowells
« Reply #4 on: December 08, 2019, 02:45:13 PM »
I have been searching for watchmakers lathe attachments for several years now and I have never seen a drilling attachment for the tool post. The usual method is to use a vertical slide with a spindle that can be set at any angle and takes WW collets.

Thanks Dan

I think that is how the Cowells pinion cutter works... or maybe I'm wrong because I've never seen one in the flesh. Those things do seem to have a tremendous amount of stuff to make the spindle go round though... apart from costing an arm and a leg. I do have a milling slide so I could clamp my Proxxon flexi drive in there. No WW collets with that option though.

I might give that a go next time around... although I suspect that finding room for both the milling slide and the tailstock might be tricky. It will also mean that I need to use the handwheels for feeding the drill so there may be some loss of 'feel'. On the plus side, the chuck should open up enough to take a centre drill... which my current arrangement can't do.

Offline steamer

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Re: Toolpost Drilling Attachment for my Cowells
« Reply #5 on: December 09, 2019, 03:04:47 AM »
I have a 8mm Shaublin unit....though its rather large.   

I'll post a pic....

Dave
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Offline steamer

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Re: Toolpost Drilling Attachment for my Cowells
« Reply #6 on: December 09, 2019, 03:20:03 AM »
Here it is
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Offline andycarlson

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Re: Toolpost Drilling Attachment for my Cowells
« Reply #7 on: December 09, 2019, 06:24:23 AM »
Thanks - that's a new one for me. Never seen one of those before.

Regards, Andy

Offline steamer

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Re: Toolpost Drilling Attachment for my Cowells
« Reply #8 on: December 09, 2019, 01:46:56 PM »
Consider getting a 8mm watchmakers lathe headstock as a beginning point and make your own.
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Offline Dan Rowe

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Re: Toolpost Drilling Attachment for my Cowells
« Reply #9 on: December 09, 2019, 02:50:48 PM »
Andy,
If you search ebay for drill chuck motor mount you should find a bunch of small 0-4mm chucks with a JT0 mount. Some come with motors and some come with the chuck and motor mount. I see mounts for 5mm shafts and 1/8" shafts. That should solve the problem of not having a center drill.

Cheers Dan
ShaylocoDan

Offline andycarlson

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Re: Toolpost Drilling Attachment for my Cowells
« Reply #10 on: December 09, 2019, 07:11:10 PM »
Consider getting a 8mm watchmakers lathe headstock as a beginning point and make your own.

Or maybe Lorch 6mm since I have a set of collets for that :)

Pity - I could have had one for next to no money from a rummage box at a show a month or two back

Offline andycarlson

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Re: Toolpost Drilling Attachment for my Cowells
« Reply #11 on: December 09, 2019, 07:12:05 PM »
If you search ebay for drill chuck motor mount you should find a bunch of small 0-4mm chucks with a JT0 mount. Some come with motors and some come with the chuck and motor mount. I see mounts for 5mm shafts and 1/8" shafts. That should solve the problem of not having a center drill.

I'll check that out. Thanks.

Offline steamer

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Re: Toolpost Drilling Attachment for my Cowells
« Reply #12 on: December 09, 2019, 11:17:35 PM »
8mm Derbyshire is far more common to get collets.   You can even get a 8mm x ER11 adapter.
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