Quartering query

[Steve Butler 1Participant @stevebutler1]

In the latest copy of ME the Barclay well tanks of the great war part 10 by Terence Holland my question is reguarding the quartering jig fig 38

I can see that one drive dog sits up against the vertical part on the left hand side of the jig as shown and is on the same center line as the axle center and also that on the right hand side of the the jig the drive dog sits on the top of the horizontal part i can see that. But my query is shouldnt the horizontal plane be on the same center line as the axle centeres and not as shown above it no dimension is shown for this hieght

Or have i missed something ?

[Steve Butler 1Participant @stevebutler1]

Question

[JasonBModerator @jasonb]

Just had a look at the earlier ME that it was in and still shown the same. Like you I can't see how it would set the wheels at 90deg unless the horizontal edge was on the axle ctr line.

It also does not give a dimension for how far above ctr line the horizontal edge is and if built to drawing teh 5/16" bolt will break through the edge if you make it to teh 3/4" dimension but will be OK if you make it to teh 1.125" dimension though the two parts are drawn the same size 

Any of our loco experts care to comment.

 

J

Edited By JasonB on 17/01/2016 18:38:18

Edited By JasonB on 17/01/2016 18:48:09

Edited By JasonB on 17/01/2016 18:50:30

[Neil WyattModerator @neilwyatt]

Its a bit odd, as the vertical one is shown in line with the axle-centre, the horizontal one is set high.

It should work, but teh angle won't be preecise. I guess he just chose dimensions to suit his application.

I'd put them in line with the centres then they out to give 90 degrees.

My own approach is a bit cruder:

[julian atkinsParticipant @julianatkins58923]

hi steve,

if you have back issues of ME available there have been numerous types of wheelset quartering jigs described over the years. i made mine up many years ago and has served me well.

not a great fan of Tony Holland's descriptions im afraid! there are far better set ups and methods!

cheers,

julian

[Stewart HartParticipant @stewarthart90345]

I'm struggling to see what the query is it looks just the same as the set up I used with a borrowed jig from my club.

[julian atkinsParticipant @julianatkins58923]

hi stew,

your club jig is exactly the same as the one i made. very good design.

cheers,

julian

[duncan webster 1Participant @duncanwebster1]

I've no doubt that ME will deny it, but are the errors in the Terrence Holland drawing due to ME's insistence on re-drawing everything? The principle of TH design seems identical to Stewart Hart's, so what is Julian Atkins complaining about?

[Stewart HartParticipant @stewarthart90345]

Posted by Steve Butler 1 on 17/01/2016 14:40:55:

In the latest copy of ME the Barclay well tanks of the great war part 10 by Terence Holland my question is reguarding the quartering jig fig 38

I can see that one drive dog sits up against the vertical part on the left hand side of the jig as shown and is on the same center line as the axle center and also that on the right hand side of the the jig the drive dog sits on the top of the horizontal part i can see that. But my query is shouldnt the horizontal plane be on the same center line as the axle centeres and not as shown above it no dimension is shown for this hieght

Or have i missed something ?

My appologies Steve having re read your post and looked at the drawing, you are quite correct the drawing is wrong the horizontal should be on the centre line, I missed that when I proof read the drawing.

Thanks for pointing the error out.

Stew

[John McNamaraParticipant @johnmcnamara74883]

Hi Steve

Using the lathe could you set the wheels in the four jaw chuck and on centre in the tail stock.

Then with a jack between the bed and one of the chuck jaws, set the crank pin against the top of a bar in place of a tool set in the tool post, that would be position one.

Then rotate the four jaw and set the jack under the next jaw and move the cross slide and tool bar to the other crank pin and set the pin against the tool bar, that would be position 2.

That should get the desired angle within a fraction of a degree, chucks are pretty accurate and the lathe is giving you good axial centering.

The jack is just a short length of bar stock with faced ends machined to fit flat against the underside of a jaw and the top of the bed, handy for various marking out and machining jobs. Unless all your chucks have the same thickness jaws you will need a separate jack for each chuck.

Regards
John

Edited By John McNamara on 18/01/2016 07:09:05

[Diane CarneyModerator @dianecarney30678]

Posted by duncan webster on 17/01/2016 23:56:02:

I've no doubt that ME will deny it, but are the errors in the Terrence Holland drawing due to ME's insistence on re-drawing everything? The principle of TH design seems identical to Stewart Hart's, so what is Julian Atkins complaining about?

Duncan, we don't 'insist on redrawing everything' for the sake of it, I promise you! Drawings are redrawn to bring them up to publishable standard. In fact, 'redrawn' probably isn't the correct term; 'copied' or 'traced' would be more correct. Original drawings are hardly ever changed in essence unless we spot an obvious error. As proof readers we tend to check primarily for faithful reproduction.

I will ask TH to have a look at this and report back.

Diane

[Neil WyattModerator @neilwyatt]

I can vouch for the standard of checking, as a series I had published before I was editor had several errors found by Stewart and Diane's eagle eyes.

To give some more detail, the main things that needs to be changed on most drawings are line weights/styles and font sizes/styles.

It may not be obvious, but we get drawings supplied at, effectively, random sizes, so the lines and fonts have to be changed to suit the size at which the drawing will be published.

An exception was the set of charts for spring design. For obvious reasons these all had to work together, and the author was very careful to provide them with correct margin allowances etc. and provide them at an exact DPI so all we had to do was revise the colour balance and convert to CMYK to suit our printing process. We also had to make sure they were printed back to back and the double spreads were in the centre of the magazine.

It is also often a requirement to move the text around to suit the space available, try and avoid colour combinations that will confuse and sometimes to re-arrange grouped items.

It is unusual with electronically supplied drawings (typically as PDFs) for the actual parts to be 'redrawn' at all.

That said, sometimes our draughtsman has to work from simple sketches or full engineering drawings on paper. and does a very good job.

In contrast, a lot of people are now supplying 'rendered images'. Usually we can treat these as photographs, but this can mean detail is lost due to reduction in size, or worse pixelisation when they are blown up. The worst of all are wire-frame drawings and screen shots – wire frames always seem to look ragged and screen shots cannot be reproduced large enough for people to read the text.

Finally, bear in mind that although we look at the drawings and try to visualise the parts, we aren't making these thing and although we look for the obvious, it is virtually impossible for us to check every mating fit is right or look interference between parts, for example. The most likely errors to get past are where someone measures up a pre-made job and makes a measurement error, or where they incorporate changes in a design after building it. Naturally, we can't tell if this is the case just by looking at a drawing.

Neil

[Steve Butler 1Participant @stevebutler1]

Hi and thanks to everyone for replying to my query i thought i had missed some other obvious point

Also thanks for enclosing photos to show other jigs

Steve

[stan pearson 1Participant @stanpearson1]

Hi Steve why not make the rods and use them to quarter the wheels

Stan

[julian atkinsParticipant @julianatkins58923]

re duncan's very valid point re me i accept my comments were misplaced and on closer study of ME not justified. my apologies. i was thinking of something else recently in print.

Stew's method is what i use with loctited wheels.

cheers,

julian

[Stewart HartParticipant @stewarthart90345]

.Just to add a little extra slat to the discussion.

I bought my loco part finished, it had been made with more enthusiasm that skill, to cut a long story short I had to remake the axle boxes and axles and replace the crank pins in the wheels the only thing I used as bought was the wheels. I had one hell of a job to get the drive rod to turn over things just kept locking up, tried all sorts to fix it without success.

Any way in desperation I made a new quartering jig as I didn't like using the screwed centres the thread was a bit sloppy and I thought that was introducing error in the quartering. I change the design to have one fixed centre the other was just a plain rod a close fit in a long bush to control the slop, See pictures.

Even with this improvement to the quartering it still wouldn't turn over, I'd checked everything and rechecked it the only thing I hadn't checked was the crank pin centres as I thought no one would get something so fundamental wrong, in the end I checked them and yes they was up to 3mm difference in the six wheels no two were the same, so I recut the so they were all the same put in some oversized crank pins and as if by magic the motion was a smooth as silk.

The moral of the story is you really need to get an understanding of the critical features that make a loco work, and never, never assume something is correct when following on from someone else.

Stew

 

Edited By Stewart Hart on 19/01/2016 12:23:35

Edited By Stewart Hart on 19/01/2016 12:27:22

Edited By Stewart Hart on 19/01/2016 12:28:21

[Diane CarneyModerator @dianecarney30678]

We might start a new feature: 'One Man and his Quartering Jig'

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Diane Carney on 20/01/2016 10:40:06:

We might start a new feature: 'One Man and his Quartering Jig'

.

Diane,

Is that intended as a hint that a few simple additions to the lathe would make a better Jig than some of the custom-built devices ?

MichaelG.

.

P.S. … As a mere observer, it has always struck me that an apparently simple job causes so much difficulty.

[IanTParticipant @iant]

I've used John McN's method (with a 'jack' under one jaw of the 4J) but my 'jack' was purpose made and carefully set to be the centre height less half the thickness of the jaw.

I remember making the jack that way but have just been sat here wondering why I took the care? The only thing I can think of is that it does mean that the jack can sit anywhere on the bed/under the jaw – without effecting the angular setting in any way. But I'm not sure it makes any real difference in practice. When used for wheel setting a small angular error (slightly off 90 degrees) doesn't make any difference generally provided all wheels are set the same.

You do these things (presumably for a good reason at the time) and later wonder why – especially if your memory for detail fades over time. I found some bits I made a few years back and I'm at a complete loss as to what they are for now. I really must start keeping a workshop diary.

Regards,

IanT

[duncan webster 1Participant @duncanwebster1]

Slight variation on John McN's method, turn a centre on a bit of bar held in the 4 jaw, then set up the axle assembly between centres with one crankpin resting on top of one of the jaws set horizontal(ish). Make up a spacer to go between crankpin and bed (or cross slide) and lock the lathe spindle. I used a gear wheel indexer on the far end, with a string round the chuck with a weight on the other end to take up backlash (high tech workshop mine!). Then transfer the spacer to the other end of the axle, rest that crankpin on it and move the crankpin at the headstock end to rest against the front face of the jaw which is vertical. Instead of the spacer you can use a bit of square bar held in the toolpost, I was fortunate in that my 4" square was just right.

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