A Stuart Turner Steam Hammer

[Chipswitheverything]

This steam hammer has been built from a set of the original Henley on Thames castings, which came with the kit of sundries for making the stop valve and oil box. I believe that these items have been discontinued, which is a pity, as they add considerably to the interest of the hammer.

 I was generously given the set of castings by an elderly friend in 1977 !  They had come to him as the residue of another model engineer's estate, and he had no plans to make the model.   Having obtained them, I did a few basic operations way back then, but was engaged with other projects  ( like making a copy of an eighteenth century writing desk - woodwork !!), so apart from various flurries when I unearthed the box of bits for inspection about every decade, the finishing of a lot of the components has waited until recent times.
 I have some pictures of the recent procedures, which I can post later, but most of it was pre digital, so no pics...

Finally and at last got it all finished ( the filling and painting took me ages ) yesterday!

In the older Henley catalogues, the model was introduced with a slightly cryptic caption about " well within the capabilities of  a near beginner ...with simple tools". And "it is not all lathe work- it calls for careful hand work with the file and will reward good workmanship "
 I'll have a bit to say later about this matter that requires the beginner to do some interesting filing!  Previous builders, ( and maybe some with the model presently on the go) , of the steam hammer will guess the feature of the design that I'm alluding to!
 I have tried the model on air in a lash up way, and it definitely works!   Fingers clear?

Dave

[Jasonb]

That looks very nice, you will have a novel way to crack your nuts this Cristmas.

I suppose back when this kit was introduced most model engineers would not have had milling machines so a lot of the time you see mention of filing the main castings flat with other work done on teh vertical slide or faceplate. I don't have the drawings for this one but is it the dovetail of te anvil they expect the beginner to file?

[AOG]

That looks great. I have a newer set of castings for the hammer "stress relieving" until I get enough experience to tackle it. How hard would you say the hammer is in comparison to something like a 10 series engine?

Tony

[crueby]

That is very very nice! I've always wanted to make one, would be interested in any pics you have of the build.

[b.lindsey]

Beautiful model Dave. And so well finished too. Very nice!!

Bill

[Chipswitheverything]

Thank you for your comments and interest chaps, much appreciated.

Tony, I think what I have to say here might give you an idea about the "Ten" and the hammer, but a lot of the work is no more difficult.

 Jason, on the castings, the anvil comes moulded in as a lump on top of the tup, with a rough simulation of the dovetail formed in the pattern. Functionally it's OK, but looks a bit crude to my mind :   all the Stuart hammers I have seen have featured that, though.  That's not the tricky bit of manufacture!, as it can be left as is.
  I sawed off the anvil lump and made a new steel anvil with dovetails and a tapered cotter.  The tup casting was of course dovetailed to suit.

The cast in dovetails had a suitable angle moulded in, so I made up a four flute cutter from silver steel to reproduce the angle, and that cut the dovetails OK.

 When I made the cotter, I measured the gap between anvil and tup at either side with feelers, and tried to set the mill up so that the bit of flat steel used for the cotter gave the "same difference" over about the width of the tup when traversed past a DTI.   Sort of worked!    With a scrap of draw filing it knocked in tightly.  I put a long cap-screw up though the tup casting to give a belt-and -braces clamping of the anvil.  ( That's why I haven't taken the anvil off in the photos, I don't want to dismantle the model again at the moment...)
 The full sized hammers that I have seen in photos mostly seem to have some sort of cottered arrangement such as this.

No, the tricky bit of this steam hammer is all to do with the gland holes in the mouthpiece and bronze gland that fits into it, because they must be formed to fit the two flats on the sides of the hammer itself.  Various solutions to doing this job have been put forward, but not by Stuart Turner, who just give out the drawing! ( See below ). Given that their blurb mentions the beginner in respect of the 'hammer, I feel that some advice ( a bit like the little blurb that accompanied the "10" engines ) might not have come amiss. 

More later...    Dave
   
 

[Chipswitheverything]

Prospective builders of the 'hammer might find it useful to look through a series of four well illustrated and written articles about making the model, written by John Bertinat.  They are in Model Engineer magazines Vol 184 nos.  4116,  18, 20, 22   ( late March 2000 onwards ).   I had done a fair amount of the model before these articles came to my notice with some back numbers, but I did take a few tips from his methods.

  JB gives details of a method of forming the tricky shaped apertures for the hammer shaft, by milling a sort of bronze or brass liner section, and soldering the little quadrant sections into gland and mouthpiece by means of the liner .  His technique seems to have been used before now by other builders, I imagine it would work well.

However, after mucking about with these sort of ideas, and putting the job off, I decided to try and machine the shape into the components by slotting on the Myford lathe.
 The photos show the set up, which exploited the Radford indexing head to control the spindle rotation, and a simple lever gadget that makes the top-slide into a hand operated slotter.  I'd made the equipment years ago.

  A small tool rather like the shape of a screwcutting bit was mounted under the  top-slide clamp.  The m'piece and the gland were both previously bored to the across flats dimension of the hammer shaft, and lines scribed at that hole dimension to give me an indication of where to stop as I did the circumferential slotting.  Slotting out this radial element worked very nicely, I did smallish cuts on one side and then the other, while slowly rotating the lathe spindle via the Radford indexer, measured the "bore" with a small telescopic gauge, and worked my way evenly to the finished 1/2" diameter.

 The flat sides were slotted out - only a small amount to remove in the four corners, really - by using a square ended tool pointing vertically, set to height with shims  ( the tool just barely touching what is left of the original 7/16" bore )  and taken across with the cross slide movement.
  I had already made the hammer itself ( years before! ), so I was able to use it as a test piece.

Happy to report that the hammer , assembled with piston and cylinder etc., does operate smoothly, with very little side clearance ( waggle! ) around the flats.
Dave
 

[Jasonb]

Looks like you got a good neat fit doing it that way, when you posted the drawing yesterday I wondered if it would be possible to make a simple broach to form the shape. I would be very similar to the method I use to make "D" shaped holes for prop drivers but with two flats rather than one.





Its a pity this one is not in production at the moment but does look like it could be fabricated, maybe one to add to my list.

[Chipswitheverything]

Hi Jason, thanks for posting the picture of the broach, that is certainly another possibility.  John Bertinat did make a long broach and use it for one of a couple of steam hammers that he made, but he seemed to have some problems with it's manufacture/ wear,  and turned to alternative methods.   To my mind, it would have been a help if Stuart ( Turner ) had at some time made up some decent broaching tooling to use in house,  and offered the builder an option of buying a kit with these flat sided holes formed, and a bore register turned on the mouthpiece, etc.  That would certainly have broadened the appeal of the model to relatively inexperienced builders.
  Ref. your note at the end, I believe that the steam hammer is in production presently, it's just the oilbox and stop valve kit that they no longer supply.   In the Model Engineer articles, JB reproduces the full Stuart drawings for these sundry items, which would be a big help for anyone wanting to make them from stock materials, and perhaps a wheel valve body casting purchased from wherever .   Dave

[Chipswitheverything]

The brass oil box on the model hammer gives a splash of polished metal to liven the appearance, but of course is far from prototypical.  The actual hammer, in an engraving that I have photographed, shows a device more like a paint pot, rather like a one shot oiler on a Bridgeport mill.  Stuart's version would be more like a brass suitcase on the side of the column!
 Anyway, it's quite an enjoyable gadget to make, and will pump a drop of oil to the "steam chest" and valve via the non return valves.
The 3/32" copper pipe supplied to plumb the oil box to the non return valve allowed 0.00% wastage of material, I only just got it to meet up with both parts with nothing cut off at all.

[Chipswitheverything]

And just to complete the photo sequence....       Mill shots are of brass lid being machined to give a step, which was fettled by filing to snap into the top of the oil box body.
Dave

[JR72]

Hi Dave
    STUNNING !! What else can I say? again your usual very high standard of model making and great photos to very well done.
I wonder what's going to be next.

Regards

John

[J.L.]

Hi Dave,
This is inspirational work. You enjoy sharing your knowledge and tips freely.
Work of the highest order.
John

[jeff l]

Dave , What a high standard you work to , impressive .Jeff

[Chipswitheverything]

Appreciate your kind comments very much, gentlemen.  Your model machine shop, John, and the Corliss engine, Jeff, are magnificent pieces of model engineering and I have enjoyed your posts about them.
 John, JR72, when you come round to see the steam hammer, do remember to bring a nice watch with you so that you can place it on the anvil and observe that the hammer can descend under control so slowly and gently that it will rest on the watch glass without breaking it!  I insist that you enjoy the pleasure of being the first to demonstrate this feature....

Here are a couple of shots of the castings being prepared for painting.  Before that stage, I had done a lot of fettling and "improving" of certain of the castings, by filing and by some machining.  The "mouthpiece" casting in particular was a bit of a poor production, with no defined flanges, just sort of thick tapers towards the inner cast surface.  An evening was spent in filing and ball nosed milling to carve out an acceptable shape on this component.  Stuart ought to remake or refine the pattern.
 I also did some milling on the width of the flanges of the top area of the column, and of the cylinder bolting flanges. Shouldn't really need to do this, but it crisped the appearance up, and gave flat surfaces for the bolt heads.
 In the end, I brush painted the model, with many rubbed down ( very fine w+d paper used with a bowl of water ) coats of enamel based primer, and a few similarly treated coats of the grey and black top coats.  Humbrol was used, the grey is just their standard gloss grey, No 5.  I had problems with the very rapid speed at which the paint dried and could no longer be brushed out. That had a lot to do with why there were many rubbings down of coats, but eventually I just about got a finish that looks OK.    When I get back to the prep and painting of the Major Beam engine bits, I think that I will have to look at spraying them...

Dave