Hi Dave,

There are quite a few ways to do this and many have been suggested over the years, some involving jigs and others lathe set-ups (needs the axle to be held between centres etc). An obvious solution is to machine 'squares' on the end of the axles and to make matching 'holes' in the cranks. Only problem with this is a) I don't know if this was prototypical and b) there is also the (not-so-small) issue of making the square holes in the cranks a good fit.

Something I saw recently however, seems a better solution for you and involves drilling holes at right angles in each end of the axles. This would require either a simple square jig to rotate the axles through 90 degrees (or a rotary device – spin indexer/dividing head etc). In my case I'd probably just use my ER32/5C (square) collect block for the job, plus a slide-on drill guide.

The cranks then have a simple slot milled in their back (width to match the pin diameter) through the centre line of the axle hole, such that you get two slots on either side of it. Pins though the axles, which are located in the crank slots will then automatically quarter the cranks if done with care. I cannot recall where I saw this now but it struck me as being a useful method for quartering wheels at the time and it doesn't sound too hard to do either. You can then either clamp or Loctite the cranks on to the axles once the cranks are aligned by the pins.

So, just to repeat. I've not tried this method myself but I do think the idea has some merit and would be a useful approach for your kind of 'cranked' locomotive.

Regards,

IanT

Edited By IanT on 28/02/2014 11:53:55

OK, – I have a memory like a sieve!

I've just realised that the wheel quartering idea (I've tried to describe above) was published in the most recent G1MRA Newsletter & Journal (Issue 240) and was detailed in an article by member David Eaves.

A simple peg jig was made to orient each wheel (or crank in this case) on the mill and he also used a square axle drilling jig too. With this method of course, if the cranks are removable, then re-setting them correctly is very simple. David used it for his G1 loco's drivers but I can't think why it wouldn't work in this situation, in fact it should be easier to do.

Regards,

IanT

hi dave

2 of my locos have outside frames and cranks. you set the quartering just like you would do if the crankpins were fitted to the wheels except if you dont have split axleboxes remember to put them on first! use loctite sparingly (you dont want to get any on the axleboxes), then pin through the sides of the crankwebs all the way through going through the centre of the axle end where the crank is fitted.

IanT's suggestion of milling flats etc is complete nonsense im afraid.

cheers,

julian

hi IanT,

i think the 2 rather complicated methods you firstly described are what would sometimes be used for return cranks for walshaerts gear, not crank webs!

there is no need to use complicated jigs or equipment to drill the crankwebs for pins once they are loctited on. just set the wheelsets up on the pillar drill table, drill through and ream, and loctite or press fit in a steel pin

of course you need a quartering jig or use the lathe between centres to loctite on the second crankweb on each wheelset accurately

cheers,

julian

Maybe I wasn't that clear Julian, but I wasn't really seriously suggesting milling any flats. My apologies if I gave that impression.

I may not have described Mr Eaves method very well either, as I'm not sure his idea has been well understood. The concept is pretty similar to the one Hush describes above, but simply uses the pins for registration rather than woodruff keys. I suspect it might be one of those things that is a lot harder to describe than to actually do.

With this method, there is no need to 'pin' the joint afterwards and there is no need at all for a quartering jig (or to mount the wheel/axle/axlebox/crank set in the lathe to quarter them). The cranks should be removable/replaceable without disturbing the quartering and without needing to remove anything else (wheels/axles) from the engine. This may or may not be useful but it doesn't seem to be a bad option to have available.

However, I think I will quietly retreat from the conversation at this point.

Regards,

IanT

The jackshaft cranks on my shunter are split and clamped to the ends of the shaft and taper pinned for location.

This makes them removable (the bearings are located in holes in the frames and can't be lifted out of hornblocks).

These arrangements are exactly as the prototype.

Neil

For what it is worth, I have used the system first described by David Eaves and mentioned by IanT and whilst it involves the construction of two simple jigs it is an absolute doddle to use and dead accurate.

Mick

Edited By mick H on 13/09/2014 07:51:56

I've been wondering about the same problem for 16mm locos as I unsure of my ability to file or broach square holes accurately enough to replicate the method (squares on squares) used on commercial locos. Rather than assembling, drilling and pinning, would it be possible to first drill holes in all the cranks on a single setup (with rods passed through the axle and crankpin holes to maintain alignment)? You could then follow IanT's method to drill holes at 90 degrees in the axles, pinning the cranks to the axles on assembly.

Incidentally Geoff, regardless of how you choose to quarter the axle, would it be possible to pin across the cranks rather than inline with their throw?  That way you could drill right through, allowing you to heat the cranks and make a tool to push the pins out.

Brian

Edited By Brian G on 15/04/2017 09:56:15

Hi Bob, that looks ok for smaller gauges (garden railway sizes) but not secure enough for 5" gauge where the coupling rods are doing all the work of transmitting power to the axles. My cranks also include counterweights and are therefore quite a bit larger.

Brian G, I was assuming drilling into the end of the axle (part in the axle and part in the crank like a key and as described elsewhere) but drilling across at 90 degrees would also work. I'd need to tip the loco on it's side to drill from underneath the crank as access from the top and sides is restricted by running boards and other fittings. I could just make the pin a light drive fit so it is easier to punch them out without heat if ever i needed to, The loctite would not be used for the pins, only for the cranks.

The pins would only really be for locating the cranks in their correct positions. Once the loctite had set it would be doing most of the work.

I'm slowly getting a better understanding of how to do it so will post an update after the first attempt. Got to make the crankpins first and then drill and ream all the holes in the cranks for the crankpins and for mounting on the axles.

Cheers.

Mine is 5" and as I said 3 motors one on each axle

Edited By Bob Brown 1 on 15/04/2017 17:13:39

So, after about 18 months of procrastination (well not entirely, i've had a few other things to do during that time) I finally bit the bullet and got around to fitting the external drive cranks onto the axles and quartering them. Wasn't quite as hard as i imagined. First I made a drawing of a jig that would hold the axles and drive cranks in correct alignment and welded it up using 5mm steel strip. This is helped by the presence of dimples in the axle ends from when i turned the axles between centres, so i turned down the end of some M5 bolts to a nice cone shape, drilled and tapped some holes in the jig, inserted the bolts and tightened them into the axle holes. That kept the axle in place while i aligned the cranks. First i drilled and tapped an M5 hole in the side of each crank so that i could insert a grub screw to clamp it to the axle. I then fitted them temporarily onto the axle ends (easy push fit), quartered them in the jig, and tightened the grub screws. After checking that they were in fact quartered correctly, i loosened the grub screws, removed the cranks and drilled shallow holes in the axles at the grub screw locations. Reassembled again and checked for correct quartering when the grub screws were tightened into the holes, then pulled apart, applied a well-known anaerobic retaining compound, re-assembled in the jig, tightened the grub screws and checked alignment one last time before allowing the retaining compound to set. All the above took about 2-1/2 hrs including cups of tea. Axles now re-mounted in the chassis.