Not only complex mechanically. There was a heck of a lot of advanced maths in designing steam locomotives.
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I’m presently overhauling a long-stored 7-1/4″ gauge loco, a freelanced, doubled version of LBSC’s Juliet design – but this evening finally carried out a minor repair on my Myford lathe!
The Workshop Gremlins had long since spirited away the knob from the end of the half-nuts lever. By chance I found a spare spherical knob on a short rod – from what I don’t know – so I modified that to suit.
That should make screw-cutting less painful. The bare end of the little lever is a bit sharp!
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All I need do now is determine why it is frequently very difficult to engage the half-nuts, necessitating briskly bringing the handle up and waiting for the next number on the dial to amble round…..
Hi, I needed four more T- Nuts for my tilting table, so today I decided to make some from a piece of 12mm thick flat black bar. After cleaning off the mill scale, I trued up all the four edges, and set it up in my vice, on my mini mill, then reduced the thickness down to 11mm, 20mm in on each side. I then mill the two outer edges and two channels, to a depth of 5mm, to form the part of the nut, that fits into the slots of the tilting table surface.
When these were done, the piece of flat bar was long enough yo make six T-Nuts, and so I drilled and tapped six holes for 6mm threaded rod, and then hacksawed two slots in each side to produce my six nuts.
Tomorrow. I will now be able to cut the nuts off the rest of the bar, in my band-saw.
Hi, I needed four more T- Nuts for my tilting table, so today I decided to make some from a piece of 12mm thick flat black bar. After cleaning off the mill scale, I trued up all the four edges, and set it up in my vice, on my mini mill, then reduced the thickness down to 11mm, 20mm in on each side. I then mill the two outer edges and two channels, to a depth of 5mm, to form the part of the nut, that fits into the slots of the tilting table surface.
When these were done, the piece of flat bar was long enough yo make six T-Nuts, and so I drilled and tapped six holes for 6mm threaded rod, and then hacksawed two slots in each side to produce my six nuts.
Tomorrow. I will now be able to cut the nuts off the rest of the bar, in my band-saw.
Regards Nick.
I am impressed. Despite much grubbing around with the adjustable parallel, my last attempt at a T-nut was much too tight and only worked one way around, which I thought was impossible.
Yours look like they will all work perfectly without further fettling.
I probably have a few more years before turning up my toes so I still have time to get something right. Touch wood. When I let the machine turn the handles everything comes out just so, the fault is obviously with me 🙁
Hi Robin, they did need a little bit of fettling, but only to smooth them down a bit and to break the corners, as it was black bar I was using, but they all fitted nicely.
Tomorrow. I will now be able to cut the nuts off the rest of the bar, in my band-saw.
Regards Nick.
Cutting your nuts off sounds a bit painful. I’ll go and walk the dog
Hi Duncan, no need to worry, no tee nuts were injured while cutting them off, and no anesthetic was needed. However, the machining went as well as expected, to produce an equal shallow bevel on each side of the protruding blade, and a little work on my Indian oil stone, produced a nice smooth tiny radius on the resulting edge. The blade was then put into my four inch vice break, in place of the ones that were supplied, which I used on a Tee bar in my Fly press, with a Vee block.
I now need to make a narrower one, for another fold at the other end, but I don’t have a suitable piece of steel at the moment, but hopefully I will be able to get a piece at the up and coming Midland’s exhibition.
Just finished the Hemingway centring microscope. Anodised using sodium bisulphate rather than sulphuric acid without problems. Maintaining electrical contact during the process is a problem. I learnt a couple of things:
1 Aluminium wire from Hobbycraft seems to have some sort of insulating coating on it which was removed easily with sandpaper.
2 Best continuous contact was achieved by drilling and tapping an unobtrusive hole in the item to be anodised and then screwing the wire into this hole. The other end of the wire was best squashed with a screw in a busbar. Check continuity before dunking.
Objective holder is brass and was coloured with Birchwood brass black.
I had a look around on the internet for titanium wire but couldn’t see anything I thought suitable (or with a trustworthy description). I hadn’t thought about welding wire so thanks for that – I’ve ordered a couple of lengths of 1mm.
With work on my steam-wagon temporarily on hold for this, I am near completing overhauling my 7-1/4″ g. version of LBSC’s Juliet.
It had stood unused for some years, and is accompanied by a driving-truck loosely based in appearance on a standard mineral wagon, and without water-tank.
So a lot of work to make the combination viable and ready for a boiler test, including temporarily borrowing the steam-wagon’s water tank first for an improvised test-set for preliminary hydraulic test, then fitted in the driving-truck to feed the loco’s injector.
Next phase, a preliminary steam-test to set the safety-valves and ensure all is working.
Robert, I can’t view your work for the moment except via the sample photo Jason has posted in a thread started today by Ian P, but from that image I see you have used rather thicker knurls than the kit provided by Hemingway envisages will be used.
This is not in itself a problem but it means that in slotting the arms to accommodate the knurls you have had to remove most of the 1/2” thickness from the centre of the arms. I wonder whether what you have left in the way of side support is going to be rigid enough to stop the knurls from flexing excessively as the knurls pass up or down a piece of work.
Bill, I was also concerned about this, so added a 2mm washer to either side of either knurl. It give me a little less travel toward the chuck, but the test piece I tried seems OK.
I noticed the thicker knurls as well, the original marlco knurler used thin knurls for a reason possibly less strain on the machine and easier to traverse although the knurl looks good from the photo
Back playing with wood for a couple of days. No, not logs for woodturning, but rather for a log burner as a Christmas present for one of the family. Finished with oil still wet in the photo.
When I built the Hemingway Knurling tool, I increased the dimensions of the required parts to allow me to fit the more commonly available knurls. I only have one picture currently but I always have good success with the tool
In my case, I wanted to use the knurls from a previously purchased knurling tool, though stupidly I didn’t measure the knurls until I was ready to slot the arms. Still, a lesson learned, plan better in the future. 🙂
Rather than scrap the parts or buy new knurls I decided to push on and use what I had. The wheels are ~9.5mm, and the arms 12.5mm, so I was left with 1.5mm either side. I did think this looked too thin so made up some outer washers at 2mm each to hopefully give some additional support. The pins are drilled and tapped straight through.
Only time will tell if this works, worst case scenario I will have to remake the arms, but at least I have learned something from my mistake.