Hi Don,
I'm a bit late reading this thread but I have thoroughly enjoyed reading your posts. Your techniques employed and attention to detail are to be admired. Boy do I have a lot yet to learn!
Nice work Don.
Simon
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Hi Don,
I'm a bit late reading this thread but I have thoroughly enjoyed reading your posts. Your techniques employed and attention to detail are to be admired. Boy do I have a lot yet to learn!
Nice work Don.
Simon
Hi Don
This is really impressive, makes the 040 steam loco I am making seem... well steam powered.
Regards
Ian
G'Day All,
Thanks again to all that have sent likes etc.
I have fabricated the pivot head for the front of the roller & after grit blasting it should look like a casting. It has been fabricated from six pieces of shaped materials & then silver soldered together. My MAPP gas torch was at it limits to keep enough heat into the assembly to allow a reasonable flow of the silver solder. The bearing housing was turned with a 12˚ taper over the height with the other pieces being cut & shaped by hand. The last image painted with aching primer to see if it would look like a casting.
Attachment 371177Attachment 371178Attachment 371179Attachment 371180
The drawing called for the chassis rails to be made from 25 x 16 x 385 channel. Fat chance of buying that! So, the two rails have been mill from 25 x 25 black bar. Also, 19 x 10 channel is required as well as 10 x10 angle. Both of these will be milled.
Attachment 371181Attachment 371182
The rear axle block was also to be fabricated, but after the heating problems for the pivot head it was machined from a 75 X 75 X 75 piece of mild that has been lurking under the bench for years. The block will be fitted with two bronze plain bearings & will be riveted to the chassis rails.
Attachment 371183Attachment 371184Attachment 371185
Currently turning the rear rollers from Ø150 x 64 solid stock. The rollers were to be fabricated also but, are well beyond my heating capacity.
This is a photo of the real deal that started it all.
Attachment 371186
Regards,
Don.
G'Day All,
Finally back in the shed after the summer heat has subsided, just too hot to do any work since last November.
I have recently finished the two rear rollers, apart from the reamed holes that will house the drive pins.
The time required, as it turned out (no pun intended) to complete, took much longer that I had anticipated. The lack of suitable tooling for this job being the main cause. I would have liked to have had a number of face grooving tools but, at a couple of hundred each the cost was too high. The bulk of the material was removed by plunging a ground HSS tool to a depth of around 5mm & increasing the diameter with successive cuts until a carbide boring bar could be then used to remove the excess material. The inner face being tapered at 11˚only compounded the problem. After 3 wheelie bins of swarf, the turning was complete. The rollers are Ø149 x 65 wide. The roller that has the stepped centre spigot is the roller that will eventually house the differential centre.
Attachment 372463Attachment 372464Attachment 372465Attachment 372466
The front rollers are being turned at present & are presenting the same problems with regard to relieving the centres.
Regards,
Don.
G'Day All,
Finally, back in the shed after the summer heat & other interruptions. I have finished both the front rollers, again turned from solid stock (Ø150 x 56) black MS. As the rollers are only ever to be rotating at a very low RPM, I have made the inboard & outboard bushes from 6061 T4 aluminium.
Attachment 378585
The steering fork has taken about 20hrs to finish & required a lot of milling using a Ø5 mm end mill for most of the milling with the inner radiused corners of the relieved section completed with a Ø5 bullnosed end mill. I was trying to make the steering fork look like it has been cast & by using a mounted point in a dramel to rough up the surfaces of the relief, I think that it will have a cast look after the outer surfaces have been grit blasted.
The folk started as a Ø170 x 30 piece of black MS that was turned to Ø168 x 25.5. The blank was marked out & set up in the mill on a rotary table & the inner diameter of Ø150 was milled to form with a Ø5 end mill using 2mm deep cuts.
Attachment 378586Attachment 378587Attachment 378588
Once this was completed, the folk blank was set up on an angle plate to mill the Ø12 grooves for the pivot trunnions that are to be silver soldered in position.
Attachment 378589
The fork blank was then clamped to a piece of 12mm plate that was bolted to the rotary table. This was to allow the relieving of centre section of the folk.
Attachment 378592
Shown here is the smaller diameter of the relief. When this groove was to depth the blank was repositioned to mill the large diameter of the relief.
Below is the fork after the relieving had been completed on both sides of the fork.
Attachment 378595
The trunnions were held in position during the brazing with a piece of Ø6 rod, threaded at both ends so that a couple of nuts could be tightened to hold all the parts together. This rod also doubled as a clamping bar for the milling of the taper that runs down to the pivot trunnions.
Below is the fork with trunnions brazed in position & the body of the fork being milled to a taper of 4˚, both sides.
Attachment 378596
And, the finished fork.
Attachment 378597Attachment 378598
As can be seen there has been a lot of effort to complete the steering fork, but I think that it was worth the effort. As I am not a welder, fabrication was not a consideration.
The forecarrige that connects the steering fork to the roller axle is now being made.
Regards,
Don.
Have to admire those results, that fork is lovely.
G'Day All,
Back again after the usual interruptions of retirement.
I have completed the friction drive transmission for the roller. I'm not sure that this is going to work effectively but, I am building the model as per the original drawings. I've made two friction wheels both with a linen impregnated bakelite centre. One has the bakelite in contact with the friction disk (mild steel), the other has an O-ring seated in a radial groove into the bakelite disk. The steel friction disk will be grit blasted to hopefully improve the frictional resistance. The original plans state that the friction wheel should be made from "hard rubber", whatever that is. I had the bakelite on hand so it has been given a trial. I will not know how successful the type of drive will be until the roller is a stage were it is drivable.
In an attempt to make the outer casing look as if it has been cast, the sides & ends have be machined from 50 x 10 black flat bar. Then roughed up with a mounted point in a die grinder to try & make it look like a casting.
The image below shows most parts of the transmission.
Attachment 381101
The friction wheel body required a 10mm square hole to fit the square main drive shaft. This was achieved by drilling a Ø10.5 hole & counterboring it 3mm deep to the diagonal size of the 10mm square. A piece of HSS was ground as shown & pressed through the wheel in an arbor press. The resulting hole is a neat sliding fit on the shaft.
Attachment 381102
HSS "broach" for the square hole.
Attachment 381103
The transmission fully assembled.
Attachment 381104Attachment 381106
Attachment 381105
The transmission in position on the roller chassis.
Attachment 381107
Cutting the transmission to differential drive pinion.
Attachment 381108
Progress is painfully slow, but is getting there.
Regards,
Don.
G'Day All,
Back again with a little more progress on the roller.
Since the last post, I have fabricated the front roller forecarriage from 1.6mm MS plate & a milled centre section. A 6mm plate jig was made to hold all the components together & then, all components were silver soldered together. The front axle boxes are made from LG bronze.
Attachment 383085Attachment 383086
Once the forecarriage was completed, I could then set the front roller assembly & the pivot head in the correct position relative to the chassis. The original intention was to rivet the entire roller together using 3/32" solid steel rivets. This created too many problems trying to get into spaces around the chassis that simply was not practical due to space limitations. All fasteners are now 8BA bolts of both large & small head varieties. Below are some images of the assembly to date. Last Saturday, I spent all afternoon tapping 8BA threaded holes. I was just about a nervous wreck by the time the last hole was finished trying to avoid breaking the taps. Fortunately, I had two taper taps as one did not survive the afternoon.
Attachment 383087Attachment 383088Attachment 383089Attachment 383090
Currently working on the steering components, a worm, quadrant gear & a steering box.
Regards,
Don.
G'Day All,
A little more has been completed on the roller construction.
I wanted the steering components to be completed before I went any further.
The worm was first. The original drawings called for an eight TPI worm which, I thought was a little too coarse. I cut a twelve TPI worm, with a Ø13 OD & a Ø4 bore. It has a M2 grub screw at each end of the thread to secure it to the steering shaft.
Attachment 383517
The worm wheel was made from some cast iron from the scrap bin, The blank was bolted to a piece of aluminium & held in the dividing head. I made a "hob style" cutter to match the worm thread profile. The dividing head was set up on an adjustable angle plate to give the required lead angle of the worm.
Attachment 383518
The steering quadrant was turned from Ø60, 6061 aluminium & then milled to the required profile. Shown with the segment of the worm wheel attached. The bolts used are 8BA small heads.
Attachment 383519Attachment 383520
The worm housing was fabricated from 1.6 & 3 mm sheet & a piece of Ø19 OD MS & turned ends. The piece of bronze tube was fitted into the ends & all silver soldered together. The bronze tube was cut out to provide the bearing surface at each end.
Attachment 383521Attachment 383523Attachment 383524Attachment 383525
The steering universal joint was an interesting little exercise.
Attachment 383526
The completed steering assembly.
Attachment 383529Attachment 383527Attachment 383528Attachment 383530
I did not receive the worm wheel to accomodate the worm as the wheel is only 5mm thick. Happily, it works well & turns the front rollers with very little effort. I intend to fill in the last tooth gaps on each end of the worm wheel to stop the wheel being wound completely out of contact with the worm.
There is still a lot of work to do but, getting there.
Regards,
Don.
That is some awesome and intricate machining, plus fabrication work that you've done.:2tsup:
Kryn
G'Day All,
Thanks to everybody that have "liked" the previous posts. Much appreciated.
Some further progress has been made on the roller. The first two images are the toothed engine to transmission drive pulleys, being cut using a formed HSS fly cutter.
Attachment 384220Attachment 384221
Each pulley then had a 1.5mm thick flange bolted to each side to act as the guide for the belt. I have used a toothed belt for the engine to transmission drive rather than chain, as I could not find a Oz supplier of short lengths of steel 1/4" pitch roller chain. Hopefully it will be OK.
The assembly of all parts made to date, are shown here in their etching primer livery next to a 300mm rule.
Attachment 384222Attachment 384223Attachment 384224Attachment 384225
Now that all the major parts have been made, the small fiddly bits are next such as the control levers, steering wheel etc.
Regards,
Don.
G'Day All,
I am still building the roller & at present trying to fit an exhaust system that will clear all the other parts. My question here is, does anyone know where I can buy heat resistant twine/string, so that the exposed parts of the exhaust system can be insulated. I cannot use heat resistant tubing from the exhaust port to the muffler as there will be a couple of flanges to deal with. Any suggestions will be greatly appreciated.
Regards & thanks,
Don.
Don, a quick search online for "2mm fibreglass rope" turned up this:
https://www.ebay.com.au/itm/KT-Fibre...-/281424986626
I'm sure there are plenty of suppliers, but hopefully that gives you somewhere to start.
Steve
Thanks Steve,
I'll start from this site & see what I can find.
Regards,
Don.