An Educated Nut for Warco WM40 (with a Bridgeport type quill)

[Spurry]

Not being in the habit of finishing one job before starting another, and being galvanised into action by Andrew M, I have started to make a quick acting nut otherwise known as an educated nut.

This makes rapid adjustment of the quill-stop a breeze, instead of perpetually winding the normal stop nut to change position.

Andrew was kind enough to give me a few hints, as other sources of info seem to be a bit thin on the ground, especially for a metric version.
Just to put into context, the cost to purchase a nut from MSC is close on £50, and that's only available in Imperial.

The threaded rod on my quill is 12.60mm diameter with a 1mm pitch. As only some part threads are engaged, Andrew reckons a 12mm tap should do the job.
I have m12 x 1.75, 1.50, and 1.25 pitches but not 1mm,  so that's as far as I have got until the m12 x 1mm arrives.

(The red blob is not blood, but nail varnish, to aid repositioning.) 

The job so far-

[philf]

The threaded rod on my quill is 12.60mm diameter with a 1mm pitch. As only some part threads are engaged, Andrew reckons a 12mm tap should do the job.

Hi Spurry,

12.60 diameter sounds too close to 1/2" to me - could the pitch be 26 tpi (0.977mm)? A 1/2" BSB tap might be a better bet.

Phil.

[John Stevenson]

I went thru this idea over on the HSM forum way back in March 2009.
Never having used One I wanted to know what locked it after you had set it with the button and was told you wind the locking nut up ??? WTF, if you have to wind the locking nut up you might as well wind the stop up ??

Plus what happens when the button disappears round the back.

Pic that someone posted at the time.



So I came up with a single stop arrangement that locked in any position and didn't need a locking ring.

Right imagine the setup the Bridgy has at the moment, one nut and a locking ring, both threaded 1/2 x 20.

Now replace the nut with a shallower 'nut' but has a clearance hole, attached to this by two pins / screws / rivets is a knurled locking ring again with clearance hole.

This locking ring is actually top hatted internally as is actually a cam ring. Inside this cam ring are two half nuts, a lot like bob weights in a dizzy, it is these that are threaded 1/2" x 20.

To operate you open the cam ring, springs, not shown, force the half nuts apart and the whole assembly can move freely up and down the quill rod.

When in position you turn the cm ring to engage the rod, fine tune to position then nip the cam ring to lock.



Two pics to show the section thru the cam ring.

Make sense ??

Never got round to building this and the old POS Bridgy is long gone and I have the same machine as Spurry.
Might ? just gee me up to doing something about it.

[Joules]

Nice CAM lock, very suitable for 3D printed applications.  Filed for future use.

[Spurry]

12.60 diameter sounds too close to 1/2" to me - could the pitch be 26 tpi (0.977mm)? A 1/2" BSB tap might be a better bet.

Phil, thanks for the interest. I spent quite a bit of time with my M&W thread gauges trying to work out the threads on both the rod and screw that holds the quill stop. The 1mm pitch fitted the long rod very nicely, and the nut has 100 divisions, so my conclusion was metric.
However the screw referred to, was not a good fit on any gauge, but according to the handbook was 3/8-24 UNF x 3/4, (on a metric machine!).

So, I've ordered the 1mm pitch tap. If it does not work there's always the other option...

John S
That is a very elegant solution. Just a wee bit of programming on the old cnc machine. Can I put my name down now for one? 
Pete

[awemawson]

John, that seems a very complex part - the original is very simple and once fitted I certainly wouldn't be without one. They only comprise three parts - the body, the button, and a spring. The button has an oval hole in it with threads only on one side of the oval. The spring presses this partial thread into engagement with the threaded rod, and depressing the button disengages the thread - very simple.

[John Stevenson]

It's not that complex Andrew given that it can be churned out easily on a CNC.
I wanted something that could lock in any position given that it has threads inside it for adjustment. Chances are you will often finish up with the knob at the back and you still have to use the locking ring for absolute security.

This one doesn't require a locking ring at all.

[awemawson]

The 'button round the back' isn't an issue in use. You slide the nut to close to where you want it, then rotate it to the precise position you need. If the button ends up round the back it matters not a jot, as next time you need to press it all you have to do is turn the nut quarter of a turn, it really is that simple!

As for a 'locking nut' you have me puzzled. Mine has no locking nut. The spring pressure pressing the button thread onto the threaded rod is quite adequate to safely keep it in place once set. I've never been conscious of mine moving spontaneously  in the many years I've had it. 

[Spurry]

Andrew, thanks for clarifying the lack of locking ring.
The thickness of the two items becomes an issue only in the restriction of the total amount of available quill down feed.

For the plunger section I have projected a diameter of 15mm-16mm, as it must enclose the main vertical rod. Obviously this could not be contained within the height of the existing nut which is 12.60mm, with a locking nut of just over 8.00mm. Combining those two items gives a depth of 20mm to play with, (to keep the same amount of total quill travel).

Although I have a written description of the requirements (thanks again, Andrew), I wonder if anyone has ever seen a drawing with actual dimensions thereon?

Pete

[awemawson]

Here you go Pete - a picture with some measurements

[Spurry]

Here you go Pete - a picture with some measurements

Great stuff Andrew.  I had not realised that the button, in use, is flush with the surface; so that's an extremely useful bit of info.
In all the other pictures I've seen, the button protrudes.  The overall height does not compromise quill travel too much either.
Pete

[awemawson]

That's because the sellers are taking pictures of their item without it being on the threaded rod, so the spring pushes the button out all the way.

[BillTodd]

you can lose the sleeve on the top of the original nut (serves no purpose that i can see)  then drill a angled clearance hole so the when tilted the nut slides free but when level the remaining thread engages. The lock nut can get the same treatment.

Bill

[PekkaNF]

There probably is many possible solutions to this one.
http://www.practicalmachinist.com/vb/attachments/f38/101636d1394305317-what-really-fast-fasteners-your-screw-screw-off-appliances-there-quick-fastener.jpg

"fast nut" or "quick nut" will fetch many choices on searc engines. My favorite is aforementioned construction with plain bore and perpenticular partly threaded bar trough it. Simple to envision and pretty straight to make.

Like this one:
https://us.misumi-ec.com/vona2/detail/110300251850/

Pekka

[Spurry]

I have a few excuses for not making any further progress on this. For one, I had to finish off my shed loo and hand basin. Got the plumbing sorted, just have to nail in a bit of wire to the water heater. No mention of the big tree removed as well. Pix attached or it's not real. To Andrew.
 
Meanwhile my m13 x 1mm tap arrived from China this morning, so the first little job was to make a couple of nuts with to test my new threaded rod. They will be utilised for work-holding for the further machining on the rod. Small end to be reduced in diameter, and cross- drilled. Other end will be slotted.

Pete

[Spurry]

There has been a little Mission Creep on this small job. New threaded rod was made at 13mm diameter with 1mm pitch.
 1. The three parts shown above assisted with work-holding to finish both ends of the rod appropriately.
 2. Component parts before assembly. The spring caused the most problems. As there was only a 6mm pocket in which to put it, it was gradually shortened until the button would clear the thread. As the security of the whole set-up depends on a small amount of thread on half of a 16mm button, I tried for the most pressure that could be obtained.
 3. Complete assembly
 4. The project so far.
The new stop that causes the auto quill feed to operate will require replacing, as the professional that fitted the DRO broke a tap in my original one.  When that has been fitted, the bits and bobs for the auto quill system can hopefully be adjusted.

Pete

[awemawson]

Looking excellent Pete - very nicely made 

[PekkaNF]

Excelent work. Looks pretty.

....
The new stop that causes the auto quill feed to operate will require replacing, as the professional that fitted the DRO broke a tap in my original one.  When that has been fitted, the bits and bobs for the auto quill system can hopefully be adjusted.

Pete

Maybe he should have gone to specsavers before giving it a "damn good thrashing"

Pekka

[Spurry]

Thanks for comments, Andrew & Pekka.
It would not have happened without Andrews inspiration and help.  I still have some machining to do on the new DRO head mounting. That will be fitted to the new stop, after the threaded rod has been removed to enable the stop to be bolted to the quill itself.
Not quite sure how problematic adjustment of the auto stop mechanism is likely to be.
Pete

[Spurry]

The biggest headache was drilling the cross-hole in the top of the threaded rod, but will not bore you with the story.
The extrusion for the scale has been replaced, now machined at both ends. New bracket for read-head fitted, with the new stop.  I obtained a small unit from Machine DRO to link the two Z feeds together, and that works brilliantly, once the + and - directions had been sorted out.
The educated nut is reachable around the mounted scale and is easy to adjust.
The graduation markings on the nut were unnecessary as the DRO gives a more reliable reading of movement, but only to the odd micron.
Pete

[awemawson]

Looks very good 

[Spurry]

Thanks Andrew.
Having fitted the new Z scale, the downfeed wheel did not now fit, interfering with the read head and scale itself (pic 1). I drew up a spacer but the reversing mechanism was a little short to operate. I struck lucky on ebay and found a wheel with a slightly smaller outside diameter, correct backset, and a boss big enough to drill for the drive pin.

Next job was to replicate the three-armed vice handle for quill downfeed. The single arm always seemed to be in the wrong position to actually use it. The new hub has three drive pins instead of the standard single in the rear face. A fixture was made to enable drilling/tapping for the arms of the hub to be at correct angle and spacing. I have made the arms 200mm, the original one being 165mm, so can be shortened if necessary.
Pete