Member postings for Ramon Wilson

You are more than welcome to what castings I have Steve - no charge but help with the postage would be appreciated. I'll have a look what's there this morning then send you a PM later.

With regard to drilling and tapping very small holes in cast for such things as lagging bolts things can be eased slightly by using a slightly larger tapping drill but a much safer way (safety as in looking after the tap) is to drill and tap small brass inserts on the lathe and Loctite them into pre drilled holes in the casting.

If you are unfortunate enough to break the tap then at least it's not in the casting.

Best - Tug

The main castings for which have sat under my bench for years Clive - just never got round to it as the above has proved more than adequate when required.

I do agree though - it's a lovely bit of of very useful kit if you have time or desire to make one.

I don't like the internal support cone centre for one reason - you need three hands particularly to keep the contact with the tap as it drives forwards.

I much prefer to hold the tap very loosely in the chuck and use the method Jason shows but always grind a small flat on the side of the tap for a positive drive even on small taps down to 10/12BA. Tap shanks are not always a standard size but if a brass tube can be drilled or found to fit and held in the chuck as a guide even better

I don't think these small Eclipse tap wrenches ae available any more but are ideal for this. This is tapping 8BA - 48 holes on two cylinder blocks without a hitch. For the smaller 10 BA and below taps I use a circular tap wrench - just a slice of 3/4 dia knurled MS with a grub screw in it to drive the tap - again on a flat on the shank. The tap is turned between finger and thumb - very sensitive feed back from the tap

I don't know how many small (5BA down) holes there were in total on the above build but all were put, without breakage, in this way or by gently gripping in the drill chuck, turning the drill on then off and as the spindle runs down use the residual motion to drive the tap in four or five threads until the drill stops. Release the tap, remove and finish by hand.

Hope that's of interest too

Tug

Just realised I had these images too - shows the smaller wrench n use

Edited By Ramon Wilson on 14/08/2022 20:02:11

Edited By Ramon Wilson on 14/08/2022 20:09:37

I used a mounted stone point at slow speed to achieve the effect on this aluminium crankcase

It could be painted over I guess but I chose to bead blast it to achieve the kind of impression of the original I was hoping for. This was not a casting but machined from solid but the effect would be similar.

I have also used an engraver to dimple the surface of bronze to give a cast impression

The tool needs to be blunt, not a sharp point for the best effect. Here's another example on a home made valve body.

Hope that's of use - Tug

Edited By Ramon Wilson on 13/08/2022 22:54:12

I was a bit too quick to condemn there Paul as I'm a confirmed Loctite user on the right application so yes, on a twin crank web shaft such as this once the cranks are set in place the flywheel (unless it's two halves) isn't going very far but, tongue in cheek aside, I still wouldn't advocate it And of course, the grub screw is heretic but it does have it's place and it does offer a much easier method of disassembly/movement if required.

I've studied a fair number of stationary engines over the years not to mention images but cannot recall ever seeing a sunken gib headed key on a flywheel - unless the slot is open ended.

Whatever, Doc G has more than enough to make a decision on but here are a few images that may help, not only on flywheels but other areas too

You can only just see the staked keys on this gorgeous McNaught Corliss valved engine in the Science & Industry (not Technology as previously said) museum in Manchester

This is the flywheel on the Galloways piston drop valve cross compound engine at the same place

A main bearing on another cross compound in the Kew Bridge museum. Built by Simpson it has an identical twin which was situated in the Strumpshaw St. Eng. Museum in Norfolk. Note the centre in the shaft, no key in the crank web and thin nuts on top plus other details.

And another main out rig bearing, more in keeping with Doc's intentions on the Hick and Hargreaves Corliss valved engine in Forncett. Note the typical variation in nuts on a renovated museum exhibit

With regard to the actual machining a slot or keyway. Like most matters there's a huge variation on the manner in which to achieve either. Regrettably however, most are not conducive with doing it on an ML7 with limited kit - to my mind that is the major factor to be taken into consideration before offering advice that the recipient would find difficult if not extremely unlikely to be able to put into practice.

Best for now - Ramon

Paul, If my last post came across as a bit short it wasn't intended to be - my apologies.

Having reread your post I went back over my own - this is from my first reply to the original one raising 'keys' three pages back

If you cut the keyway parallel and you can slightly taper the key by careful filing until it tightens in the right spot but it will only be on the high point of course. A parallel key with a tiny grub screw is much the better option - the key does the driving, the screw just enough to keep it in place laterally.

On that note I shall say no more - on this matter

Best - Ramon

Edited By Ramon Wilson on 11/08/2022 08:54:06

No one in the right mind would use Loctite to fix a flywheel in place. Loctite has its right place in engineering but this is not one of them - That would make the flywheel and crankshaft a one piece item to my mind. Whilst not an actual issue it's just not a direction someone making a representation of a full size engine should consider to my mind. Once it's on it's on and IF it needs to be tweaked there's no chance.

I may not have made many engines by some counts but I have made enough to know that the option of taking things apart is one definitely required on any build.

By comparison to most the the Twin Vic flywheel is wide - without seeing the mating part in relation ship there is no indication of length of the key as shown in the original drawing

I was merely trying to point out that short tapered keys may not provide the drive in the long term if fitted in the intended way - from one end of an open slot.

I cannot think of a single example where a part is assembled to a headed key fitted within a closed slot. No doubt there will be someone with evidence to the contrary but it just doesn't make sense to me based on what I have seen over the years.

As always it's down to choice - I know what I would do and fitting a headed key into a closed slot is not one of them

If the intent is to make something as close to full size is there then why not do it and fit the keys in the proper way as already said grub screws are a compromise.

Edited By Ramon Wilson on 11/08/2022 08:24:00

No Doc nor would I, but your original drawing was.

However short of knocking on the flywheel (and off) with the key already in the slot which of course one can do so easily when it's in your hand that is very unlikely full size - which is what I thought you wanted to try to replicate. My apologies for this misunderstanding.

I have found some old photographs this afternoon taken at the Science and Technology museum in Manchester. I can't scan them but I can take an image so will do so later. there are several details that may be of help.

Yes I agree Jason but I said Doc's key as drawn - marginal at best.

What you show in your drawing here is a much longer shallow taper key with a considerable length of 'drive' and much improved This is just as I described in my three examples above but the taper filed on top is even shallower and the fit over a longer length very tight (radially) as well as a good fit in both slots. No matter how slow a taper it will only bear on one point of course - if over tightened be ready for that slight but possible tilt though a wide flywheel such as this that should be minimal and yes, as I said too, a discreet grub screw is all that's required to prevent lateral movement along the shaft - something despite the eight keys I did on the Corliss flywheel

The two keys at 120 degrees as recommended will of course give a three point contact - personally if I were to be fitting multiple keys I would be milling three or four flats on the shaft

I found this pic of the 'staked' flywheel on the Corliss in the Forncett museum - a bit dark but you can see the annular gap and the four keys if you click on it

BTW how do you insert or extract the gib key from the sunken slot and  flywheel in your first image (previous post) if such a long taper is machined on

Edited By Ramon Wilson on 10/08/2022 15:34:19

I really do think we are all confusing each other on this one

I thought we had already established that a tapered key in a matching tapered slot is totally different kettle of fish and not relevant to this model - and no, its should not require a grub screw to hold it in position

From the outset I said the object is to DRIVE the flywheel by a key - I agree you will be doing this with Docs drawn key but only by a marginal area. That marginal area, as previously stated, will soon wear in my opinion with the starting torque inertia and lead to rocking. It is not the correct way to fit such a key.

I did not say the key IS a dummy but that it could be - with the drive taken up with a hidden, sunken, key within the width of the flywheel - a far more substantial means to drive the wheel. The headed keys could then be dummies

I haven't built twenty models but those I have I have tried to replicate full size practice where possible. That adherence is not needed, it's certainly not a necessity and I'm not advocating it should be a consideration but the means of drive should be sufficient for the task. I don't consider this so

I used the word compromise and this is what I attempt to do - not always possible of course but I do try. An example is the Marine Compound crankshaft - the coupling and flywheel mount are keyed with sunken keys - full size there would be no flywheel and the coupling would, in all probability, be forged in situ with the crankshaft. Eccentrics would likely be split to enable removal. On this model eccentrics are solid and both coupling and flywheel mount will have a very small grub screw to retain them longitudinally but will not play a part as such in the drive

Docs question at the outset was about tapered keys in a parallel slot (though at first I did think he meant a tapered slot) - I'd like to think that I've tried to answer and show that as best I can

Best - R

I really must be getting old! I just checked the Waller, Double Diagonal (which is as far as I am aware a true scale model of the original) and the Mc'Onie.

All have headed keys as shown in your sketch Doc but I know I made them parallel, slightly over thick then filed them with a very slow taper so they bind tight - they are all of course driven from the ends of the respective shafts

(This shows the drive gear but the flywheel is done in the same fashion).

There is nothing wrong with this method but you were saying that the key you have will only stop where it touches and then be held by a grub screw. The small area of the key will soon wear from the inertia of starting and you will have a rocking movement develop quite quickly - only my opinion of course but that's how I see it and it's there for what it's worth.

As Hopper suggests there is absolutely nothing wrong from a practical point of view with using a simple grub screw either - it's just that I was under the impression you were going to make this engine as similar to an original one - in which case grub screw drive (Oh we do need the facility to underline at times) was not in my thinking

Not trying to confuse you Doc , certainly not intentionally for sure

R

Well isn't that what I said in the first instance Jason

I'm not familiar with TC article and not sure what you mean by the HEAD side of the wheel but lets just get back to basics. We need to fit a flywheel to a shaft on a representation of a large stationary engine.

Now we can do it to absolute scale on one hand or reduce it to the most simplistic grub screw drive on the other. Somewhere we need to meet in the middle with a fair workable compromise.

We need to drive the flywheel round by the crankshaft so need a basic means to attach the two to do so and a simple straight key is the easiest option (setting aside the need for two at 120 degrees for the moment)

If - the keys are made as shown then the ability to slide them in from the end has to be there - that means slots in the shaft where they shouldn't be - for this representation.

If Doc really wants to show keys of this nature then it would be best to have them without slotting the shaft - ie as full size, on flats - or live with extended keyways in order to do so. Obviously if not on flats these would be dummies and would soon lose their grip so a means to drive the wheel has to be there - one slotted sunken key out of sight and two or more dummy keys to hide it - compromise complete. There would not be the need to do the second slot at an exact 120 degrees to match anything if so.

The other alternative would be a simple discreet but more adequate grub screw that provides the drive but as said that defeats the object

Doc picks up on both our points about the single point contact - just touching so not influencing the wheel to any degree. That's not a satisfactory drive to me - if the grub screw is doing that then the keys a dummy anyway

I guess I'm repeating myself so I'll shut up now - flogging and dead horses spring to mind

Edited By Ramon Wilson on 10/08/2022 10:49:57

A wedge type key that you show would be used to apply radial force to hold the flywheel in place hence the gib or head to enable extraction. It would likely be used on the kind of flywheel you wish to represent in three's or four's in order, as Jason has already pointed out, to apply equal radial force and to eliminate tilting as already said - 'staking a flywheel' I believe, is the correct terminology but this is usually when the flywheel has clearance to allow the tapers to trim any slight misalignment the wheel may have as well as retain it

Unless the slot is accessible at an open end, ie the end face of a stepped shaft, this is not the type of key to use in a slot cut in the shaft. Unless it has a matching taper as Paul has pointed out, it's short diminishing surface area is the only driving force.

Such keys would usually bear directly on the shaft surface - usually on flat faces and usually from both sides of the wheel.

A sunken key on the other hand can be across the full width of the wheel and is captive by the slot - it gives full drive and only the smallest grub screw is require to prevent lateral movement of the wheel. If it's made smaller than the width of the flywheel then you could put dummy keys in to represent gib keys

I'm assuming you didn't see my previous post re the cutter?

Edited By Ramon Wilson on 10/08/2022 09:28:14

Paul,

A tapered key mating with a tapered slot will I agree not influence the plane of the flywheel but as previously said a tapered key in a parallel slot fitted tight enough sufficient to locate the flywheel firmly (and at one end only) will influence the flywheel rim if there is the slightest slack in the bore to shaft make up. If tapered keys were used in such a fashion three or four would be used. Jason's thought are the same as mine here it takes very little difference at the shaft to put the rim out of kilter perfectly witnessed when running of course.

Broaching - again, as already said, is fine if you have the broaches and the means to apply them. Totally agree, if you make a broach guide at 120 degrees then the angular accuracy is readily attained. That is the way I broached this wheel. Though I made the guide at home I broached it using the broaches and broaching press at work. Not quite the same when you only have an ML7 to use.

Apologies for the bold - the means to underline text would be much better!

Doc,

As mentioned previously, yes you can machine the tool bit from Sil St and it should do the job fine but just harden it, I wouldn't temper it. The tool needs backing off on all sides - particularly the width otherwise it will rub and wear as the slot deepens producing a key way with tapered sides! Definitely not what you want.

This op on a lathe is one that has to be done slowly, even with a one thou cut, the force require is considerable. Again on an ML7 with that small saddle wheel as a driving force a huge difference from a Marlco broaching set up - and a larger lathe of course. The wider the key the more force required. Jason's idea of roughing first is one way of getting round this but to my mind at no more than 3mm wide it's best done in one hit.

The tool/ toolbit holder needs to be short and reasonably substantial if flexing is not to occur. That will produce a tapered key way of unknown angle.

It’s not like me to simplify things, but I can’t see any huge issues? *

(* disclaimer - I’ve never done this before)

This is not a difficult op Doc but it has many potentials for slight error that will be only too obvious when fitting the key(s)

Unless things have changed Jason I always thought the ML7 had a 65 tooth bull wheel - I believe there was something designed for it (New Zealand designer I think, name escapes me) to enable division but not direct division. I think the image you show is a Super 7 which has a 60 tooth wheel - here is my set up. This could not be done on my previous ML7.

Well 'proof is in the pudding' as they say so I bow to your skill on the four keys - excellent work, in fact very crisp indeed

To use the chuck jaws though, I'm sure you would agree, you need to have a positive stop for the jaw to impinge upon - and, unless exactly the right height to place the jaw dead horizontal, in the same position each time - and a means to hold it in contact whilst machining takes place. I think you'll find given the gap bed on a 7 you would not be able to stand a stop post directly under the jaw (may be wrong on that without checking) To my mind it would not take much deviation to create a lot of fitting issues but as you have proved, it can be done on your lathe.

I'm not saying using the chuck jaws is not viable just that it's not necessarily an ideal way to go about it generally

Best - R

Edited By Ramon Wilson on 09/08/2022 09:53:55

Posted by Ramon Wilson on 08/08/2022 20:30:34:

Yes, I'm with Jason on the (non) use of a tapered key. If you use the saddle to cut it in the flywheel you can't cut it at an angle anyway. How do you plan to cut the keyways in the parts to be fitted BTW

If you cut the keyway parallel and you can slightly taper the key by careful filing until it tightens in the right spot but it will only be on the high point of course. A parallel key with a tiny grub screw is much the better option - the key does the driving, the screw just enough to keep it in place laterally.

I have just cut the keyways in the coupling and flywheel drive ends on the Marine Compound. The issue how to hold them in place poses the same question so a discreet grub-screw it is.

Sorry to quote myself guys but that is exactly what I said - once more bearing in mind the kit at Doc's disposal ...

The slot in the shaft for the key is obviously parallel and done on the milling machine or in the lathe if you have a cross slide milling attachment and can lock the spindle

The keyway in the flywheel is for the most part and certainly in Doc's case likely to be cut using the lathe as a shaper. The only difficult part about that is A, to accurately shape a cutter of the desired width and B, to position it dead on centre line. The spindle does need to be held from rotating and he best way to do that without a purpose made spindle lock is to use the lowest back gear.

Getting the two keys at the same angular position however without a positive dividing device on both is flying on the seat of your pants - as said before personally I'd put this to one side - idealism is one thing reality is another but as always it's about choice. It's a lot of 'accuracy requirement' for little or no positive effect save for the satisfaction of trying and possibly some scale effect.

I made a slotting head for the Super 7 that can be set to cut a tapered keyway but have never had to use it in that fashion save once on the Bentley but that was at an angle on a tapered surface.

Here it is being used last week on the couplings referred to

There is still the difficulty of grinding the tool bit (by hand) to the right dimension at the same time as keeping it equal about the tool bit diameter but for a one off this could be milled in silver steel with far more accuracy.

Despite being very careful in slotting the shaft the slots were slightly oversize so a stepped 2-2.15mm key had to be made at one end and slightly less at the other

Broaches are fine - if you have them and the means to use them but they still don't cut a key on a taper - not that that is necessary as explained above and confirmed by Jason's comments - the key, from one side only, will induce tilt no matter how good the fit of flywheel to shaft. If you really want a tapered key as you show - to tighten the wheel to the shaft - then you need to do one at each side

The flywheel just has to go round and round - it isn't going to have to drive anything but it doesn't want to move radially (rock) on the key - getting one to fit just right is a task on it's own - two at 120 degrees is just making things (very) difficult for yourself.

But, as always, choice is choice and yours alone to make

Ramon

PS Jason - Doc's ML7 has a 65T bull wheel so can't be used. The only option on a 7 is a dividing attachment in the rear of the spindle. Personally I would not rely on using the jaws to get the accuracy to match that of the dividing head (RT) used to mill the shaft

Edited By Ramon Wilson on 09/08/2022 08:34:13

Who would need model engineering to fill their lives when you have such a beautiful creature to be friends with - WOW indeed!

What a remarkable situation to be in on a daily basis. I like to think that i have never been envious of anyone or anything but have to say that could well change my outlook Joseph - you are indeed a very fortunate guy.

Nearest thing I have is the Rottweiler 'Rocky' next door who puts his head over the fence on a daily basis for a Bonio - Big dog but soft as a brush

Best - Tug

Yes, I'm with Jason on the (non) use of a tapered key. If you use the saddle to cut it in the flywheel you can't cut it at an angle anyway. How do you plan to cut the keyways in the parts to be fitted BTW

If you cut the keyway parallel and you can slightly taper the key by careful filing until it tightens in the right spot but it will only be on the high point of course. A parallel key with a tiny grub screw is much the better option - the key does the driving, the screw just enough to keep it in place laterally.

I have just cut the keyways in the coupling and flywheel drive ends on the Marine Compound. The issue how to hold them in place poses the same question so a discreet grub-screw it is.

Same with the centres - either is correct - just depends on your view. Bear in mind though if they are to be left in then they do need to be quite small to be in scale. If you turn the ends away it usually has to be done using a fixed steady if you cant get the shaft up the spindle.

Regards - R

Not forgetting this lovely example of an Easton and Anderson compound at the Forncett Steam Museum.

Always thought this would make for a lovely model project too

Bit late in the day for me now though

Tug

Better luck this time Doc, hope you had a good break.

Best - R