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WW1 Dennis truck find

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I have a slotter of a similar vintage and a bit closer to you if you feel the need!

 

Thanks Adrian. You are very kind.

 

That's an interesting suggestion Matt. The taper would give me a nice datum to work to. I hadn't thought of that one but I could do a nice job with a bit of care. Unfortunately, my lathe is only 3 1/2" centre height and even Dad's Colchester can only turn 14" in the gap so we are stuck for capacity to bore the wheel. I could make a steel bush that way and screw it on the back of the wheel though so that could get around it.

 

A shaper would be nice to have. My garden shed couldn't cope with it though. A lathe, a mill, a bench and me and it is packed!

 

Spark erosion would do the job but I think it would have to be the wire eroding type which Barry so kindly organised for us to cut the splines in our drive couplings. I understand that the CNC wire eroders are now so sophisticated that the wire can be leaned over during the cutting process and would cut the taper for us perfectly so that is a good solution.

 

Dad sent me this picture of the steering column today and the mating surface is pretty poor. Wire erosion is too good for this! I am coming to the conclusion that I shall drill the wheel through at 5/8" diameter and rough out the square with a file. Then I shall make a square broach the size of the small end and pull that through. Finally, I shall gently dress the hole out from the 0.689" to the 0.730" of the large end, a bit at a time using blue to see where to cut and then thump it onto the shaft to get a firm fit. Some patience will be needed here but I think I will manage. Just a bit of care needed although I shall swear if I overdo it! Then it is back to making a bush to go in from the back!

 

Many thanks for all of your suggestions.

 

Steve

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Stupid question, what's a Broach?

 

Hi Tony.

 

Good question! I have never seen one used commercially but acquired this one in a box of bits. This one is for cutting keyways in a disc/crank/sprocket or whatever. The previously made plug with slot is put into the hole in the disc and the broach introduced into the slot. It is driven through in a press with each tooth cutting a couple of thou. After the first pass, the shim is placed in the slot and the broach is pushed through again for a second cut. Shims can be added until the slot is the correct depth.

 

The problem that I will have is that to cut a square hole, the broach must have teeth on all four sides and can be passed through the hole only once. This will test my toolmaking skills to the limit and I hope not to disappoint Marcel!

 

Steve

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The problem that I will have is that to cut a square hole, the broach must have teeth on all four sides and can be passed through the hole only once. This will test my toolmaking skills to the limit and I hope not to disappoint Marcel!

 

Steve

 

Can a broach similar to that shown not be used several times to cut out each side of the square in turn? I can't see how a four sided broach can work on the first pass where it would be cutting on all four sides.

 

As far as a blued fit onto the column. I don't think the current condition of the taper on the shaft would reliably transfer a good and consistent amount of marking to the hub on subsequent re-fits. Unless of course you refinish the shaft first by building up with metal or filler and re-shaping to a smooth finish. Given that the aluminium hub of the wheel is soft the good whack with a hammer should do much to sort out any slight discrepancies in fit. Occasional re-tightening of the centre nut may be required as the hub relaxes to a better fit.

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As you can see the home workshop can easily afford square broaches of all sizes!

broach.jpg

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[ATTACH=CONFIG]35725[/ATTACH]

 

As you can see the home workshop can easily afford square broaches of all sizes!

 

A very clear incentive to make your own!

 

Tony

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turn a taper on keysteel (1040)1/3 to 1/2 the lenght ,turn undercuts with a turning tool to make the cutting edge, heat bright red quench in oil makes about ten holes before its worn out

cheers mal

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That's fine for a hole with parallel sides but not for a tapered hole. I would bore a tapered hole and file to fit as Matt suggested.

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turn a taper on keysteel (1040)1/3 to 1/2 the lenght ,turn undercuts with a turning tool to make the cutting edge, heat bright red quench in oil makes about ten holes before its worn out

cheers mal

 

Thanks Mal.

 

That's more or less what I have in mind but I plan to use silver steel ('drill rod' to our cousins across the pond) so I will have to machine it square first. I have tried key steel before but the piece I used didn't have enough carbon in it to survive more than one washer. The taper is still an issue of course, but as it is only 0.040" over 1 1/2" length and the male surface is so poor, I think I will get away with some careful filing.

 

My next challenge is that my press is not wide enough to accept the wheel so I will have to put a thread on the end of the broach so that I can attach a stud and pull it through. It's a lot of effort for just one hole!

 

Steve

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As Steve mentioned earlier wire cutting tapers is relatively easy. For normal parts with parallel sides the wire feed and exit tubes are co-axial so that the wire is held vertically. If the feed tube is displaced to one side the cut is tapered. In practice both the feed tube and exit tube can move completely independently of each other. This means that taper cuts of 30 degrees or more can be achieved. Clever software manages the positioning as the wire cuts arcs with tapers. Apparently the 'Party Piece' for wire-cutters is for the feed end of the wire to be profiling an elephant whilst the lower end profiles a horse, so you end up with a lump of steel with a horse on one end, an elephant on the other, and a blend of the two in the middle!

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It's a lot of effort for just one hole!

 

Steve

 

Now, come on Steve, after all the effort the three of you have put in so far, what's another hole? The quality of the pictures and your continued workmanship continues to amaze. I look forward to seeing it at Brighton!

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I may have caseharden it

 

Ah! that's where I went wrong. I must admit that machining a round bar square and then promptly turning it round again is a bit of a chore. I haven't found a source of square carbon steel that I can machine so key steel is a good substitute.

 

Thanks!

 

Steve :-)

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Hi,

 

when I replied to the original thread, I had not seen the state of the square taper. 0.040 thou taper is really nothing to speak of. You could probably push a coarse square file through as a broach if you can find on the right size. Due to the pitted rounded square, I would be inclined to make a thick steel washer with a square hole to act like a flange. File fitted to the square and scewed with counter sunk coarse set screws up into the Al. Due to the state of the square, without building it up, I wouldn't trust it alone in the Al. I imagine the steering is going to be heavy on the Denis, the leverage of the steering wheel is going to be pretty high. Making a broach is more work than fileing. With a bastard square file with chalk on it and a card or wire brush to clean the file as you go, it won't take long to do it by hand!

 

Regards, Matt

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Don't know if this helps but I asked my machinists about this - they suggested bore & file square or bore and use a slotting head on a mill, indexing the wheel over to achieve the taper.

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Steve has been keeping himself busy and has converted the old adapter flange that the lorry came with into the spacer for the carb. You may remember the temporary one he knocked up out of a chunk of plywood so we could start the engine:

 

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Edited by Great War truck

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I got a little confused there until I worked out you'd posted the pics in reverse order - silly me :nut:

 

Gordon

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I worked out you'd posted the pics in reverse order

I don't think he did.

Tapped holes plugged and silver soldered. flange squared off....

I love silver soldering, very satisfying process when it goes well :)

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Ah, OK, duly corrected. :-D

 

I'll go back to sleep now and wait for the next installment.

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Tony returned to the Headlamp Brackets today and they are now well on the way.

 

The "stems" are almost oval in section - and tapered and they are being made from of 30mm square black steel. They had previously been cut to length and the correct angles machined on each end so that the Headlamps would end up in their correct positions - clear of the Radiator Defender and also would not foul the wings when the wings are fitted.

 

The "stems" then had to be taken down to 3/4" in thickness to match the big "U's" which hold the lamps.

 

The "stems" were then made oval in section by firstly removing a lot of the surplus steel with an angle grinder, and then near finished with a file. They remain to be final polished.

 

The three parts of the assembly are screwed together at present but they will now be welded together for full strength - and then tidied up.

 

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A few years ago, we were fortunate to be able to inspect the four ton Dennis at Cobham Bus Museum and took some photographs of missing components. One of these was the footstep which is mounted on the chassis frame on the near side.

 

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As you can see, it was very heavily painted and well used but provided enough information for us to make a copy. Steve set about it this weekend and started with hacksaw and file to produce the blank, 14" x 9".

 

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This was straightforward but he had been puzzling for some time over how to make the pimples. Eventually, he came up with a press tool in the shape of two buttons and a strap to keep them in their relative positions.

 

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The buttons are made of silver steel, hardened right out and then tempered back yellow.

 

He put it in his press and had a few goes with differing shapes of punch until he found something satisfactory.

 

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Once that had been sorted, he marked out the pattern of pimples and then cut a small dimple with the tip of an 1/8" drill at each point to give a location for the punch.

 

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Then it was a case of get on with it.

 

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It has taken all day to push them all in but the result is really quite pleasing.

 

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On another front, we expect to pick up the hardwood for the body frame next weekend and Father is going to order the steel tomorrow. Steve is now doing the detail drawings for the ironwork which will be our Christmas project.

Edited by Great War truck

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This step looks far too good to paint! Could they have been chemically blacked originally as painting doesn't seem appropriate?

Edited by Asciidv

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They might have blacked it for a nice shiny fire engine but I suspect that a quick coat of green would have been more likely on an army lorry!

 

Steve :-)

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