WW1 Dennis truck find

[Great War truck]

he then offered the mounting up to the engine after the four fixing holes had been drilled - thankfully a perfect fit.

 

 

 

 

Back to the Drill to put in the Lubrication hole from the engine to eventually join up with the groove inside the bore - final hole to be drilled - tomorrow - and then plugged.

[Great War truck]

And it's all coming together. Just three more castings to do!

 

 

 

[Great War truck]

The final holes have now been drilled in the Mounting - a 3/16" lubrication hole to join up with the machined slot inside the bore and tapped 1/4" BSF on the bottom for a threaded plug. Steve is making the screwed plug as he has a slitting saw attachment on his lathe and will be able to cut a clean screw-driver slot in the plug.

 

The other hole is 1/2" and is simply a drain hole.

 

 

 

[Great War truck]

The completed Mounting - now put to one side to await the completion of the other parts before final assembly.

 

 

 

Tony is now addressing the final big casting - the main body of the pump. The casting is not very "clean" around the centre and he is trying to get as much of that muck as possible off it before machining it to try to save the tools. The gaps or spaces around the middle are quite small so this is not an easy exercise.

 

He has cleaned up the outside "seam" on the casting left by the two parts of the pattern by "draw-filing" it.

 

 

 

 

[BenHawkins]

It is great to see the progress and I look forward to borrowing the patterns for my water pump.

 

In the article on the Dennis subsidy lorry in the automobile enginner (September 1917) it talks about the drain hole in the pump casting being plugged by an "ignorant" driver resulting in water passing into the base chamber (sump).

 

I will take a photo of the pump gland spanner used by the RCS motor club. It is not an original Dennis one but it seems fairly effective.

 

Ben

[Old Bill]

You will be most welcome to borrow them. We will be only too pleased to see them used again after all that work!

 

This is the later pattern pump and is a better proposition all round than the early one. In this one, any water leaking from the gland or oil from the bearing end will simply trickle out and run through the drain hole. On the original, there was no proper gland, just a flat face and a fibre washer and the drain hole diverted the water before it reached the bearing surface which was pressure fed from the engine oil pump. If you blocked the drain hole, the water simply ran right through and into the sump! You might be able to see it in the drawing of an early pattern pump below.

 

Steve

[Gordon_M]

It looks like any water passing by could drain out directly underneath the washer setup, or am I wrong?

 

I'd guess that the change from early to late, and the addition of a stuffing / packing gland, would correspond with a change from an unpressurised system to a pressurised one maybe? Were the early trucks run without a pressurised water jacket but the later ones with?

 

It would be the pressurisation that would tend to drive water past the gland I think.

 

Gordon

[Old Bill]

No, that is quite right. The water would drain straight out. It was this hole which was reported as being blocked (See Ben's comment above) so that the water could work its way right along the shaft and into the sump. I guess it would be OK whilst it was running but the water would run in overnight when the oil pump wasn't doing anything. The water seal is made by the shaft being sprung from right to left and a flange on the shaft trapping a fibre washer against the face of the pump. I guess it was more a controlled leak than a seal.

 

I don't think the Subsidy lorries ever had pressurised systems. The gland just has to resist a head of two feet of water. I am hoping very much that the gland will require little attention as it appears to be a pump strip-down job to repack it!

 

Steve

[Gordon_M]

I am hoping very much that the gland will require little attention as it appears to be a pump strip-down job to repack it!

 

Steve

 

Well, we still use this sort of stuff on cheapish oilfield valves, which have external stuffing glands not unlike this setup. These days the packing gland is energised from one end, and is in its own chamber, which also has a grease fitting so that stuffing can be injected ( ooo errr missus :-D ) from an item not unlike a grease gun. Wouldn't work unless the majority of the packing material was enclosed though, which it doesn't seem to be on the original design.

 

Be wary of over-tighening it initially, which will cause it to warm up and 'fire up' Leave it relatively loose and even let it drip a little till it has run awhile, then just tweak it up.

[Great War truck]

Tony has carried out preliminary machining operations on the Pump Body. Chucked it by the outside of the body first of all so that the face to take the cover could be machined. This had to be faced off and then bored out so that the cover would slip in snugly.

 

 

 

 

 

He then turned the Pump Body around in the Chuck and held it by its newly machined surfaces. Took preliminary cuts on that and bored it out to finished size to take the Mounting.

 

 

 

[abn deuce]

That is some pump , it would appear to be able to circulate enough water to cool a huge engine seems to be a bit over sized , still you are going by the original specs and it is what it is .

[Gordon_M]

It is large, but since the system is unpressurised it will have work to do - the ability to move water would depend a lot on the engine revs too.

 

Next question then, and apologies if you have already covered this in the last 71 pages - what maximum engine revs does the engine run at, and is the pump drive geared up by pulleys or does it turn just at engine speed?

 

Gordon

[Old Bill]

This pump turns at half engine speed as it is on the same shaft as the magneto. The engine probably tops out at around 1400 rpm so the pump is at 700. You can see why it is so big! The post-war version of the engine has the pump axis parallel to the crank and is independently driven from the timing gears. I don't know the ratio but suspect that it runs at crank speed as it is about half the size of this one.

 

Steve

[Great War truck]

Today Tony bored out the Pump Body to take, firstly the Pump Drive Shaft and then opened up part of that same hole to take the Gland. Reduced the depth of the previously machined faces to the final correct thickness, but the Pump Body will ultimately have to be reversed in the chuck for 3/16" to be taken of the other faces to give final correct thickness or depth of the whole unit.

 

 

 

Here we have

 

 

The Pump Drive Shaft in position with the Gland on it.

 

 

Now with the Gland Nut hanging on the shaft and

 

 

showing where the gland nut will ultimately screw on.

 

The final job to be done on the body whilst it is still in the lathe is to screw cut the thread on the Gland Boss to take the Gland Nut - 2" x 16tpi.

[Gordon_M]

It does occur to me that WW1 trucks are more of a challenge. There's just no way you can phone up a dealer for most of this stuff, and the WW2 emphasis on standardisation hadn't kicked in.

 

As a contrast I think there are two types of Dodge water pump that cover the entire Dodge truck fleet, 1/2 to 1.5 ton, from 1939 to 1947, and both of them can be bought off the shelf. The same basic pump was in use from about 1934 to around 1968, so even if you can't get the exact original it is relatively easy to get something very close and adapt it.

 

-----------------

 

The sort of techniques you are using used to be common, but are disappearing quickly. In the 1970s I worked in Carron Company in Falkirk (Carronades, cannons - Henry Shrapnel came her to develop - well, Shrapnel, as the company was good at the precision casting < chequer > that was necessary on the outside of the grenade housings to get them to burst correctly) There was a machine shop with all sorts of interesting kit in it that never looked like it was used, most of it WW2 period, or at least installed then.

 

Being of an enquiring mind I questioned the value of this stuff, so one day, when there was a shop breakdown on a big production machine as a gear had stripped or worn out, the elderly (actually he was historic, but a really nice chap...) engineer invited me to drop in to that shop during the day at odd moments. During that shift he used a power hacksaw to part-off a length of gear blank from a bar, lathed it to size, and set up and machined a helical spur gear with keyway from scratch, roughly the size of a truck diff main ring - the gear was in place and working at the end of the shift.

 

I saw right away that he used about half the machines in the shop on that one gear, and did so quickly and easily. In fact he just set up the blank on most of them and let it run on power feed while he was doing something else. I did notice he seemed to be the only one in the entire company that could use even one of these machines, and I suspect that when he did eventually retire ( he was already long past the formal age ) all the perfectly usable machines just had to go in the bin because no-one else could operate them, and no other company would want to take them on for such irregular use. Of course the kicker is the next time one of the big machines broke a gear Carron would have lost a lot of production till it was fixed by a sub-contractor, and if the sub-contractor couldn't fix it ( or more likely couldn't be bothered ) an otherwise perfectly serviceable machine would end up as scrap.

 

I'll bet most of us have similar stories of;

 

" you used to be able to get that made / fixed / designed / built from scratch just down the road from here twenty years ago but now it has to come from Germany / India / China / a specialist in Outer Mongolia who charges an arm and a leg to talk to you, and it'll take six months "

 

I'm raising my tea in your memory, Hector, as that was around forty years ago, and I'm sure you are tending machines at a much higher level these days... :angel:

 

( Maybe we need a thread to promote companies in the UK that can still do some of this stuff - no commercial interest posts, of course? )

Edited March 7, 2010 by Gordon_M
spelling again

[Asciidv]

Gordon, I think most people who read this thread will only agree with your sentiments. Making parts 'in -house' certainly ins't fashionable. Most 'manufacturing' companies just assemble with all component manufacture sub-contracted out to define part cost and to drive part cost down. It means that sub contractors work on very narow margins and is the reason why so many are disappearing.

 

Machine tools in the UK have never been so cheap as they are now, so it is time to sanp up the Herberts, Harrisons, Colchesters and Bridgeports and carry on the tradition of your 'Hector' which Steve and Tony are doing so well at maintaining,

 

Barry.

[Great War truck]

Further progress. Tony cut the 2" x 16 tpi thread on the Gland Boss on the Water Pump.

 

Not a straight forward exercise where he would have preferred to have used an ordinary straight external thread cutting tool, but the thread is half buried within the casting and the Bolting Flange for the elbow sticks out too far and would have been in the way for a direct approach at the thread in any case.

 

So to overcome these difficulties, he ran the lathe in reverse and used the same internal cutting tool that he used to cut the thread in the nut, but on the far side of the tool post. This worked just fine and the nut screws on comfortably.

 

 

 

[Great War truck]

The Pump Body can come out of the lathe now, but he did a trial assembly of it with its associated bits whilst it was still held in the chuck. Looks OK.

 

We still have to take 3/16" off the thickness of it from the other side and drill and tap various holes. The required stainless steel screws and studs are already made up, so this just leaves the two elbows to machine before final assembly and that will be "job done"!

 

 

 

[abn deuce]

GWT there must be a fair amount of swarf from all the machine work that has been undertaken , how much would you estimate so far ?

Edited March 7, 2010 by abn deuce
correct text

[Old Bill]

Thanks Gordon and Barry. You are right, not many people or places make things any more. In fact, I am beginning to wonder who does make all the stuff!

 

I am always very impressed with Fathers willingness to tackle all of these things and just have a go. When I was very little and he was a bank clerk in the Isles of Scilly, he told Mother that he was going to build a railway engine. He went and bought a lathe, a book on how to use it and built a steam locomotive which I think was really quite enterprising. Later on, when he was a manager, one of his customers came in for a loan. In his hands were some bits of metal. After he had his loan, conversation turned to these components. They were bits of throttle linkage for a Field Marshall tractor which required some work.

 

'I'll do that for you' said Father. The chap was most impressed. He had visited the bank and got not only his loan but his tractor fixed as well! That's customer service in a Devonshire country bank for you!

 

Steve

Edited March 16, 2010 by Old Bill
Spelling!

[Great War truck]

Tony did some more machining on the Water Pump today. Cleaned up the top flange on the Body which will take one of the angle pipes and the Boss for the Drain Cock.

 

 

 

[Great War truck]

He then turned his attention then to the smaller angled water pipe. Held it in the machine vice to just skim the bottom so that he had a flat surface to hold it on. Then set it up on an adjustable Angle Plate in the Milling Machine so that he was able to bore out the pipe to 1.5" to take the copper delivery tube. Another straight forward operation.

 

 

 

 

[Great War truck]

Just a little bit more progress today:

 

 

 

[Great War truck]

Tony set this up in the Milling Machine so that he could fly-cut the big bolting face. This all straight forward with no problems.

 

 

 

 

Then bolted the casting down to two "parallels" so that he could then machine the smaller bolting face which will take the hot water pipe to the Inlet Manifold Jacket.

 

Then the "jinx" on this casting returns following Steve's headaches with the pattern - and porosity has reappeared in this face when it was being machined. It is as deep as 3/8".

 

However, I do not think that this is terminal in that this "hole" can be filled - it does not go right through - and we think that it can be avoided when the "bolt-down" studs are fitted. Nevertheless, disappointing again!

 

 

 

 

[abn deuce]

Damn that is a shame , so close !!!:wow::banghead::banghead::banghead: