1/3rd Scale Allman Vertical Engine

[Jasonb]

This is a kit based on the 3/4HP Vertical engine by Allman Gas Engine Co. of New York in 1/3rd scale. The kit was available for a short run from Debolt back in about 1990 and my kit had passed through a few hand before finding it's way to me.

There are not that many castings to the kit but it does include a few lumps of bar stock and a good set of hardware including fixings, springs, gears, valves etc





As you may be able to guess from the cardboard box my set came across the sea from the Emerald Isle





The previous owner had made a tentative start by turning the bottom of the base flat and cleaning up the lower part of the main frame casting which is the grey primes area in the photo above, he supplied these couple of photos .







Having studied the main base casting for a while and used the height gauge to see where the various cuts would end up I came up with a plan of attack.

First was to machine the two bearing cap mating surfaces and tidy up the sides, I also added the stud holes and tapped for the oilers. Having the caps machined to this stage would save me having to disturb the main casting once I started working on it.



I spent a while squaring things up on the mill and deciding where best the centre line was and then machined the other mating face for the bearings to height and tapped for fixings.





Then using a 3 tooth 40mm dia indexable milling cutter I cleaned up all the outer edges.



The gap between bearings was too big for the 40mm cutter so I changed to a "little hogger" which is 1" dia to clean up the inner faces. You may notice that the bearing blocks are now narrower than the "cast" columns below when infact they should be narrower, one of the downsides of using castings. Still only a minor issue and nothing that cant be dealt with as you will see later.



While set up in this position I drilled the 4 mounting holes in the base, this required making an extended pilot drill and then opening up with an extra long 6.5mm drill which is a good clearance size for the 1/4" fixings.



There is also a tapped hole required for the rocker arm pivot which was drilled with the above two sizes followed by a 9mm extra long bit.



I was just able to get the quill down far enough to guide the top of the tap while it was turned with an open ended spanner.



More work on the base to follow.

J

[Jo]

Jason's got another set of castings  This can't be right  I thought you said something about you don't need castings, you prefer to make engines out of bar stock.

I like the new lathe 

Jo

P.S. I can free of charge send a courier to relieve you of any other casting sets that are hindering your progress with your bar stock engines   

[Tennessee Whiskey]

Jason,  WTF, you've seen sneaked one in on us and stirred the "Queen of Machine" in the process  . Is this one finished? 

Cletus

[b.lindsey]

Finished or not, nice looking set of castings and a nice looking engine too!! They are obviously well aged

Bill

[NickG]

I like these old vertical engines, something a bit different to look at when they're running.

Sent from my LG-H340n using Tapatalk

[Jasonb]

Cletus, you should know me by now, unlike queenie this one is not only finished but also running I want to tweak it a bit more before I slap some paint on it but that should be done by the time I get to the end of the build thread.

Jo I thought I better get this one out the way then that only leaves me a couple of those nasty casting sets left getting in the way, although the two I have left will require a lot of scratch built work for what I have in mind for them, one being something I have never seen modeled before. I do find this so much more rewarding than just knocking out the same old models that have been built time and time again.

As you should have guessed from my response to that list of castings you e-mailed yesterday there is not a lot that interests me particularly if they are overpriced or have faulty castings, my currently being worked on engine being a perfect example of this.

[Jasonb]

Bill, you noticed that brown aged patina then

Nick, that was one of the things that tempted me to this kit, its quite an old design and has sufficient different parts and construction to keep me interested unlike a lot of the horizontal push rod hit & miss engines which are just different versions of a similar thing. I may even be tempted to try and convert it to hot tube ignition like the original had once it is running completely to my liking.

[Dave Otto]

Hi Jason

Good to see you posting another one of your fine builds! I picked up one of these engines second hand a number of years ago as a Mechanics kit (all parts machined by Debolt); and thought that it would be fun to try to make it more like the engraving in your intro post. I will most likely never get to it and will probably just let it go.

It will be fun to sit back and watch how you finish yours.

Dave

[zeeprogrammer]

 

Should be fun.

Kinda too bad you've already seen the end of the movie. 

[b.lindsey]

Kinda too bad you've already seen the end of the movie. 

Yeah I hate when that happens. But it does reduce the chance of banter and the odd recipe taking things off track

Bill

[Jo]

As you should have guessed from my response to that list of castings you e-mailed yesterday there is not a lot that interests me particularly if they are overpriced or have faulty castings, my currently being worked on engine being a perfect example of this. 

The Corliss cross compound wins the prize of being my most expensive set of casting I have ever paid for at £300 inc P&P (actually they were hand delivered By Peter Southworth  ). I wouldn't mention you paid more than that for this set of castings

Kinda too bad you've already seen the end of the movie. 

Yeah I hate when that happens. But it does reduce the chance of banter and the odd recipe taking things off track

Bill

And the chance of Jason having to admit to doing something wrong 

Jo

[Jasonb]

Dave, I'm probably going to leave this one more or less as per the Debolt drawings, there is another version of this engine by Alyn Foundry which is a hot tube ignition one so that would be more suited to getting the correct shape of the linkages etc. This would not be hard to make from scratch if I go down that route. I will hopefully at some time have castings for the other Allman engine which has twin A frames rather than the tuning fork so that is another option.

Zee I'm affraid there won't be much mention of food in this thread, having got it from a pile of castings to a running engine in 8 weeks of evenings and part weekends there was not much time for things like eating

Jo I suppose it comes down to rarity and desirability, anyone can go out and buy a set of new Southworth castings today. These engines were only done in small runs and that was 30 odd years ago so there are not so many virgin sets about. You also need to allow for the fact that a lot of the good stuff has to come from far away and previous owners like to recoupe the substantial postage costs and any duty paid. Mine was also hand delivered by a very nice man. You have also been spoilt a bit by having a tame supplier who can be beaten down on price especially when he has over indulged his machine addiction, the rest of us tend to have to pay the going rate.

Luckily I don't seem to make as many errors as some so that is why you won't see many in my threads but they will be there when and if they happen.

[Jo]

Jo I suppose it comes down to rarity and desirability, anyone can go out and buy a set of new Southworth castings today. These engines were only done in small runs and that was 30 odd years ago so there are not so many virgin sets about. ...... You have also been spoilt a bit by having a tame supplier who can be beaten down on price especially when he has over indulged his machine addiction, the rest of us tend to have to pay the going rate.

The Corliss Cross Compound is very rare and  extremely desirable but more than a bit daunting for most model makers. The castings are done to order as the set works out at about 58Kgs and as Peter said to me they take up a lot of space so he did not keep them on the shelf (it would have needed to be a very strong shelf). How many finished Cross Compounds or for that matter Double Tandem Compounds have you seen? Or even Videos of them running 

There are people out there who will pay foolish money for a 'rare' set of castings  I pay up to and not beyond the standard second hand casting set price of 50% of the manufacturers original cost and however desperate my supplier gets he never undercuts his original cost   .

Jo

P.S.  That makes  three sets of castings I think I should send up a courier to relieve you of one of my casting set's big brother 

[Jasonb]

Right, back to the build

I now had a flat base and 4 square faces on the bearing blocks so could easily locate the casting for the next operations. Two angle plates were clocked in across the mill bed and the DRO zero'd on them so all hights could be set out from the base. I used two of the mounting holes and an additional two G-cramps to hold the base to the angle plates.



With some support under the frame and a jack between the forks the first job was to machine the cylinder mounting face flat and to width followed by adding the six holes for the mounting bolts.



At the same seting I then moved up the casting and drilled then bored the two bearing holes which should ensure they are at right angles to the cylinder. To keep things nice and rigid I made up this 20mm dia bar which was about as big as I could  put down the 7/8" hole, fitted nicely into a 20mm ER32 collet.



The casting was then turned 180deg and the various holes for the timing gear, governor and cam follower done. I also machined back the surface of the casting to the required setbacks from the bearing edge.



Turn the casting again and pop in the two 8BA holes for the lubricator bracket and spot face the area around them



Thats about all the work to the main casting, just some clean up that will be done later



For a break from the castings I next made up a few of the steel components that fit the main base, firstly the rocker arm pivot, quite straightforward turning and threading and a HSS tool to do the large concave part.



The live electrical contact consists of a ring that is held to the crankshaft by a grub screw, after turning, boring and parting off it was held in the soft jaws to face to thickness.



Then a flat machined and hole tapped to take the contact stud.



And here are the two completed parts along with the governor latch adjusting screw and rocker arm link



Finally for this installment a few more steel turnings - Crank pin, Latch pivot, Cam follower pivot, conrod small end locknut and latch spring pin.



J

[Jasonb]

The most obvious thing to machine first on the cylinder casting was the large flat area where it attaches to the main column. A few packers underneath allowed it to be clamped down level to the bed and a similar arrangement with an angle plate behind made sure it would not roll. A 40mm indexable tipped cutter flattened the area and then six mounting holes were drilled and then tapped 1/4" BSF.



If you look closely at the two holes on the right you will see the rear one is far closer to the edge than the one in the foreground, this was due to the two halves of the casting being almost 3/32" out of line This will be attended to at the final fettling.



While set up like this I machined the two sides of the mounting pad straight. Once transfered onto the lathe carrage this edge was clocked true while the casting was packed upto ctr height. Luckily my largest between centres boring bar just fitted the cored hole so that was used to bore the cylinder.



With that done a flycutter was used to machine the head end back to finished length.



Moving back to the mill and using the same angle plate the 4 head stud holes were drilled and tapped 2BA and then it was out with the extra long series drill again to put in the water passage, you may just be able to see the black mark on the drill that shows where it had to penitrate to, all with only 1/8" between the hole and main bore, luckily it did not wander though I almost drilled it in the wrong place but luckily double checked after spot drilling the hole.



The Allman has a similar arrangement to the Gade where there are two exhaust ports, one being the usual valve controlled one at the top end of the stroke and another in the sidewall of the cylinder at the bottom of the stroke. The mounting face for the header was first machined flat and the stud holes tapped. Then a slot milled and finally 4 holes drilled through into the bore.



The spark plug hole and top water outlet are quite straightforward, just milled flat, drilled & tapped.  You can also see that the lower water inlet has been done in the lower left.



The inlet and outlet valves are on opposite sides of the cylinder. The inlet will be covered later but the exhaust is a bit awkward as it is accessed through the inlet opening which required the valve seat to be cut with a long CSk rather than machined as I prefer.



You may be able to see the blue areas where the valve was touching the seat and the clear where it was not This was slight chatter From the CSK so some lapping was required.



The final job was to drill a passage up through the cavity behind the exhaust valve to join two of the four holes that lead to the header. This was then tapped for a plug as was the long water passage hole.



The cylinder head is a simple turning job from a bit of CI bar. it then needs clearance for the two valved and spark plug cut which I did by plunging with milling cutters.



Finished cylinder and head.


J