Myford QC Gearbox Project.

[Pete W.]

Pete

Now you have it sorted do you know that to cut metric threads all you need is a 33t and a 34 t gear to replace the output gear from the banjo if my brain cell is working its a 24 t

these are not to nasa standards but are very very close and cheaper that the metric kit ale you retain most of the fine feeds

Stuart

Hi there, Stuart,

Thank you for your post.  Yes, I am aware of this and I already have the relevant two gears plus the chart that goes with them, courtesy of John Stevenson via 'the Bay'.  Still, your post may draw the attention of other Modders to this facility for cutting threads that are not too long (i.e too many turns). 

I have quite a bit of work still to do before I'm in a position to actually use my QC Gear-Box.  The first thread that I anticipate cutting is 1/4" BSF.  I shall probably rough cut with the QC Gearbox and a single point tool and then finish with a die in the tail-stock die holder. 
If you examine my last batch of photos closely, it looks as though the Woodruff key fell out of the lead-screw gear while I was fitting it!          
I didn't notice it until I was posting the photos on here!           So attending to that is going to be my first task when I get back into the workshop.

   Back in the 1970s, I met a gentleman who was a director of the Barking Brass-ware Company (I hope I've remembered the company name correctly).  He told me that they were still cutting threads on bathroom taps etc using hand chasers.  He gave me to understand that the scrap-rate was negligible. 

[lordedmond]

I have seen thread chasing done .i think it's a confidence thing just dig it in and follow, they used a tool with a stout handle held under the armpit

It looked hairy but it worked and has been used for donkeys ages

No worries about the gears as you say others may not know, I use JS gear for quickies but break out the proper metric banjo for government jobs,

Btw next project for you would be the Graham Meek clutch, I have one for the big bore Gray did the drawing from dims from my lathe all done via Email , I do not leave it on the lathe all the time those two gears get a bit hard on the ears even though I have poor hearing as there is no way to completely disengage the unit but it does work great

Good work on the RDG effort at Myford bits the old works where only 5mile away

Stuart

[krv3000]

hi it all cuming together well 

[Pete W.]

Hi there, all, and thank you, Bob, for your encouragement.

I've been stalled at a ridiculous stage of this project.  Here's an extract of the Illustrated Parts List (aka 'exploded diagram') of the right-hand end of the lead-screw:



(I must apologise for the printing being positioned over some of the detail.)

Item #7 is the drive pin that engages with the lead-screw hand-wheel.  (I couldn't find a usable picture of the hand-wheel - imagine that item #5 is its hub.  As you can see from the diagram, the drive pin is supposed to be fitted into the cross-hole in the end of the lead-screw, it's a light press fit and has to go in after the collar (item #55) has been fitted and the lead-screw passed through the right-hand bearing (items #60 & #61).

I have two drive pins which have come out of two lead-screws.  The problem was I couldn't persuade either of the drive-pins to go into the hole in the lead-screw I've fitted to the lathe.  I was reluctant to get heavy with a hammer, either with or without a pin-punch, for fear of bending the lead-screw.

I tried spinning the drive pin in the lathe and gently stoning it but that didn't work.  A big part of the difficulty was offering up the pin squarely to the hole.  In desperation, part of my fevered brain started to design a screw-jacking device          but calm returned.

Eventually, I ran a succession of twist drills through the hole, starting with one that was an easy fit and stopping when I reached one of a few thou less than the measured diameter of the pin.  I still had to coax the pin into the hole with light taps of the hammer but it seems to be fitting OK now.  (I recently visited a relative who has a Myford Super Seven with QC Gearbox and he said that the drive pin in his machine tends to drop out!)  If I'd overshot the mark with the drills, my back-up plan would have been a drop of Loctite!

Having dealt with the drive pin, I fitted the lead-screw hand-wheel. 
When I took it off the old lead-screw, there was a 7/16" washer under the nut - the shed gremlins seem to have run off with that!!          

The securing nut, item #6, is a 7/16" BSF Simmonds nut.  The original had a locking ring of red fibre but age has taken its toll of that and I can tighten or loosen it by hand. 
About twelve months ago, I had bought a couple of 7/16" BSF Nyloc nuts but the shed gremlins have run off with those too!          
So I adjourned to the 'Bay and ordered a few more, with washers.  They're promised for Friday delivery - I bet the original ones will turn up tomorrow (Thursday)!          

[dsquire]

Pete

Lovely job your doing of presenting the Myford QC Gearbox Project. 

I think you might want to have a sharp word with those work shop gremlins before they get totally out of control. 

Cheers 

Don

[Pete W.]

Hi there, Don, and thank you for your encouragement.

SNIP
The securing nut, item #6, is a 7/16" BSF Simmonds nut.  The original had a locking ring of red fibre but age has taken its toll of that and I can tighten or loosen it by hand. 
About twelve months ago, I had bought a couple of 7/16" BSF Nyloc nuts but the shed gremlins have run off with those too!          
So I adjourned to the 'Bay and ordered a few more, with washers.  They're promised for Friday delivery - I bet the original ones will turn up tomorrow (Thursday)!          

It was worse than that!  As my head hit the pillow last night I had a flash of inspiration - I'm currently holding in my hand the two 7/16" BSF Nyloc nuts!          
They'd never got out to the workshop but were in my 'study' all along.   

[Pete W.]

Hi there, all,

Well, I fitted a 7/16" washer and a 7/16" BSF Nyloc nut to the RH end of the lead-screw and adjusted the nut to take up the slack without being too tight.  Then, just to be sure, I checked the 15 thou clearance between the face of the gearbox and the back of the lead-screw gear (see earlier post) - all was OK.

According to the Beeston Myford fitting instructions, the next stage is to align the top of the gear-box casting relative to the upper surface of the lathe bed.  They recommend using a mag-base on the lathe carriage with a clock gauge on the bar and touching the top surface of the gear-box casting (with the gear-box lid removed).  Then, with the gearbox fixing screws finger-tight, to rock the gear-box until both ends give the same clock reading.  They suggest using either wooden wedges or screw jacks under the LH and RH ends of the gear-box. 
I opted to use screw jacks, only I don't have any!          

So, to paraphrase Mrs. Beeton, I had to first catch my mild steel hexagonal bar. 
That came to hand quite easily - the shed gremlins must have gone to watch the Rugby!          

So, I cut off two pieces about 2⅜" long, chucked one in the 3-jaw then faced and centred one end.  I reduced a length of ½" to ½" diameter and drilled a hole down the centre of the bar, opening it in stages to #12 (tapping size for M6 thread) and started the taper tap in the hole.  NB. power off, turning the chuck by hand.

Then, I remembered I ought to take some photos, here are a couple of views of this stage:



and



Next operation was to change to a round nose tool, swing the top-slide round 30° and turn a tapered shoulder like this:



and



I reversed the job in the chuck and opened out the hole to just under ½" and deep enough to just leave enough meat to match the reach of the taps.  (That doesn't warrant a photo.)

Then I transferred the job from the lathe to the bench vice and completed tapping the hole M6.  A quick draw-file on the flats of the hexagon and fitted the screw and it looked like this:



I bought the screws with the wobbly pads - next time I'll buy M8 rather than M6.  Now I need to make a second one, you can see the raw material and screw in that last photo.

I think I shall lay a parallel across the top of the gear-box when I do the alignment, it'll save the clock probe from falling down the hole!          

 

[Pete W.]

Hi there, all,

And then there were two!!!



Next workshop session will put these to use. 

[Pete W.]

Hi there, all,

The next stage was to level the gear-box.  This is how the Beeston Myford installation instructions tell you to do it:

 

That picture shows two wooden wedges - the text says you can alternatively use screw jacks.

Having reviewed all my mag bases & fittings, I discovered that I didn't have the means to mount the mag base on the lathe saddle and position the dial indicator over the extreme left-hand side of the gearbox! 
          

Miking the mag base rods revealed that they are between 9.5 and 10 mm diameter.   I'm sure to have a long enough bit of steel rod that diameter, aren't I?  No, I hadn't!          

What I did have was a shaft from the old ex-WW2 bomb-aimer's computer.  That was long enough and had sections at each end that were just over 10 mm OD.
So I turned those sections down to fit the mag base joints (including machining off the rather nice worm wheel on one end!)

That enabled me to rig up the following set-up (it's so wide, it took two photos):



and



I'm sorry that the flash has washed out the clock dial.  What you can't see in those photos are the two screw jacks under the gear-box, one each end, in lieu of the wedges.

Once I got that set up, the actual levelling of the gearbox was almost a non-event!  Winding the saddle back and forth to traverse the probe of the dial indicator along the parallel and adjusting the jacks accordingly, eventually there was no change of clock reading.  I suppose, to be sure, I should have turned the parallel  end-for-end and tried again but I didn't think of that until I started to type this post!  When I was satisfied with the levelling, I tightened the gear-box fixing screws and checked again.  Then I dismantled the mag base & dial gauge and refitted the gear-box lid.

The next stage is to fit the gear back-plate and gear-quadrant and check for freedom of rotation with no binding.  Then I have to get some SAE 30 oil and put the right amount in the gear-box.  Apparently, it has to be plain oil with no additives (like the detergents in engine oil) and although it's for a gear-box, it doesn't need to be EP.   

[Pete W.]

Hi there, all,

Here's a bit of an     No photos, I'm afraid.

I've fitted the gear quadrant and checked the entire gear train for free running.  I did have an initial scare because there was a regular 'thump' when I ran the machine under power.  Luckily, that turned out to be a bit of something in one of the gear's teeth, cured with a toothbrush.  I don't think it was metallic swarf, more likely a fragment of cardboard from the box it's all been stored in since I bought it.

I went looking for 30 grade motor oil to fill the gear-box, asking for plain oil with no fancy additives.  In particular, it doesn't need to be EP oil.  I eventually did buy a 1 litre flagon though I'm not convinced it's 'plain'.

Once I've put the oil in the gear-box I can, in theory, use the lathe even though the gear cover is not yet fitted.  The outstanding work on the gear cover is to drill and tap the 2 BA hole for the spring catch and then to fill, rub down and paint it.  I'm a bit scared of that job, having seen Mick-s results on his L5!!

However, before I can do that, I really do need to spring clean the shed, particularly the bench.  Also, if I am to use the lathe, I need to attend to its regular lubrication.  That means I need to rehabilitate my two Beeston Myford oil-guns.  I think the more modern one is usable but the original, shorter, gun that came with the lathe always leaked oil out of the filler cap.  There's a leather washer in the cap but it only has about ½ mm of the wall thickness of the oil-gun body on which to seal.  I do need that one because the more modern gun is too long to fit between the workshop wall and the oil nipple in the rear of the saddle.  While I'm giving the lathe's lubrication system a going-over, I've bought some 2 BA oil nipples in case any of the originals are clogged.

If any other Modders have succeeded in taming the leak from the original oil-gun, I'd be pleased to hear from you - I hate the feel of a handful of Nuto H32 let alone the waste! 

[Pete W.]

Hi there, all,

It's been quite a time since I last posted on this thread but here's a minor   

The gear-box installation instructions include one to shorten the lead-screw shield that's attached to the left-hand side of the saddle.  I've looked back through this thread but I can't find where I mentioned the amount of shortening.

The thing is, Beeston Myford seem to have compiled the gear-box installation instructions on the basis that the lead-screw is all in one piece.  However, many lead-screws, including mine, have a coupling just to the right of where the lead-screw emerges from the gear-box.  This interferes with the lead-screw shield with the result that the saddle can't reach the edge of the gap, see photo:



(Sorry about the soft focus!)

So I guess I shall have to take it off and shorten it a bit more, probably by about another ⅝". 

[millwright]

well Pete apart from that little problem i take it its been a success then. i ended up reading the whole thread again.
well done.

John

[krv3000]

hi its geting ther 

[Fergus OMore]

This NUTO32 thing? It's one of those famous old wive's things. Go out and buy ISO32 Hydraulic Oil which is -according to my informants- the same. In case you don't want 5 litres which is dead cheap and you can splash it about, you can buy a drop from Halfords etc for topping up High Bollock Jacks.

As for this SAE 30 stuff- who cares?

 My Super7 box blew up- not because of the oil but because the previous owner used mahogany dust in a dry box. Cut 2 new gears and whatever and filled it with oil -oil. I think that it was multigrade but if you think about rationally, car oil changes its viscosity with heat. Myfords only heat up with discussion

Cheers

Norman

[Pete W.]

Hi there, Norman,

I wrote 'Nuto H32' out of habit.  I actually use ISO32 hydraulic oil which I buy, 5 litres at a time, from my friendly local agricultural engineers' suppliers.  I've posted this on more forum threads than I can remember!

It's the same stuff that farmers use in those whizzy hydraulic gizmos on the back of their tractors (cue: Andrew!!!) and farmers don't like paying more than they have to! 

(That's not a criticism - they're an example to us all!)          

[Fergus OMore]

Fine, I go to the (err )blenders

Somewhere I have a copy of the Myford S7B stuff but it seems no different to what you have already.
Somewhere else is a copy on how to make a box. Interested?
Cheers again

Norman

[Pete W.]

Hi there, again, Norman,

If you mean how to make a QC gear-box, no thanks, I'm hoping the one I have will see me out!

What I would like is an easy way to seal the filler cap on the original Beeston Myford oil gun.  Mine has a disk of leather in the cap but it can't possibly seal on the edge of the 5 thou thick body of the oil gun.  If there were a flange on the end of the body, it wouldn't be possible to assemble the 'innards'.  I've toyed with the idea of making a drop-in metal disk with an O-ring groove round its outer edge but it's never yet got to the top of the 'to do' list.   

Somebody described the ML7 lubrication arrangements as a 'total loss system' and so it is, so my swarf tray is always swimming in oil.  The front mandrel bearing emits oil that gets flung off from the chuck back-plate and paints a vertical stripe down the wall and the front of my workshop coat. 
I can put up with those - what I really don't like is trying to get oil into the oil nipples but, instead, getting a handful of oil from round the oil gun filler cap!!!          

The later Beeston Myford oil gun is better in that respect but needs to be parked in a spout-upwards position - I have some Terry tool clips to screw to the workshop wall to achieve that.

I can use the later type gun on all the oil nipples except the one on the rear of the saddle.  Because my lathe is close to the wall, only the early pattern gun will fit in the space!

[Fergus OMore]

Good Morning Pete

I'm afraid that it is going to be a bit of a ramble- but it gives how much that I know and just how little.

The Myford oil can thing occupied much of contents of Model Engineer at one time- when? I cann't remember but a new oil can came on the scene. Again, I recall( vaguely) that some aspiring geyser removed the balls or the spring or reduced the back pressure on the nipples. Sounds clinically horrendous but there is food for thought. My oil can works- no leather or whatever- a bit of red card stuff.  So the ramble continues( sorry) and some other geyser concocted a oil system from these garden small bore watering systems. If you remove the balls and springs( ) it should work.

Oddly, I'm a lazy guy and use a cheap -non Myford oil can and a bit of plastic to oil the parts that other oil cans cannot reachI Apologies to the lager advert)

Loss of oil on a ML7? Cleeve did something about re=cycling it . It was one of his tight fisted but useful comments on the his ML7.

You'll have to forgive yet again a ramble but I still have some of the ML7 Cleeve articles. Model Engineer forced us to destroy our postings but when Jim Early died- I got some- not all sent to me as a 'friend, brother and beneficiary'

Ok- aplogies but an old man rambling in the hope that it might stir up a bit of thought

Regards

Norman