Doc Posted April 8, 2017 Author Share Posted April 8, 2017 Will do Pete. How's your 20" dob coming along? Link to comment Share on other sites More sharing options...
Tweedledee Posted April 8, 2017 Share Posted April 8, 2017 13 minutes ago, Doc said: Will do Pete. How's your 20" dob coming along? The heating system in my workshop/sun deck/driveway seems to have been broken for about six months. Now the weather is improving, I hope to get some new inspiration and the spare time to make some progress again. I am now at the stage where I don't need to spend much more money on the project, just allocate the time for doing it. Since the actual engineering and woodworking aspect has never been my day job, it just seems to take me an awful long time to do a small amount of work. This is not helped by the fact that I am a bit of a perfectionist. I have been known to spend a couple of days on a part, only to scrap it and start again because I wasn't totally happy with my workmanship! Link to comment Share on other sites More sharing options...
Doc Posted April 9, 2017 Author Share Posted April 9, 2017 Item #9 next which are the top cylinder covers. I wanted to make the tops profiled like the plans but I don't have any profiling tools and maybe lack the skill as well. I tried grinding a dome profile tool but it was a bulls up so binned it. Anyway I just made the top chamfered instead. There is enough meat on the item to dome it at a latter stage. Once again most important point was to get the lip a nice tight fit in the cylinder. +Graham 1 Link to comment Share on other sites More sharing options...
Tweedledee Posted April 9, 2017 Share Posted April 9, 2017 Aluminium, bronze and brass does look good together. Link to comment Share on other sites More sharing options...
+Graham Posted April 9, 2017 Share Posted April 9, 2017 That is taking shape very nicely Mick. Keep the updates coming. Link to comment Share on other sites More sharing options...
+Graham Posted April 9, 2017 Share Posted April 9, 2017 If you want to turn a radius / dome on those Mick get one of these. Made especially for the Myfords. https://www.rdgtools.co.uk/acatalog/BALL-TURNING-ATTACHMENT-FOR-THE-MYFORD-LATHE-6097687.html Link to comment Share on other sites More sharing options...
Doc Posted April 9, 2017 Author Share Posted April 9, 2017 On my ever growing list of items to get Graham. Cheers buddy. Link to comment Share on other sites More sharing options...
Doc Posted April 10, 2017 Author Share Posted April 10, 2017 Next item #24 the pistons. These were cut from 2" aluminium bar and was machined to the correct diameter. After a few attempts I managed to get the diameter to 0.001" under the size of the cylinder. I then cut the groove for the O Ring with a parting tool. Next came the M5 thread through the middle and final operation was to part it off and machine to the correct thickness. Tried sliding them into the bores and they were a nice tight fit. I still have to hone the cylinder bores so once that is done and the O rings are fitted it should be a wonderful fit, keeping my fingers crossed. tuckstar 1 Link to comment Share on other sites More sharing options...
Doc Posted April 12, 2017 Author Share Posted April 12, 2017 A little more lathe time and this was to make the spool valve and eccentric strap spindle top items #33 & #34. This was all made from brass rod and hexagon bar and turned on the lathe. The spool valve diameter is pretty critical as it runs inside the spool liner which is basically just a brass tube which is honed. I used the threading tool to make the grooves in the spool valve. Teslar and tuckstar 2 Link to comment Share on other sites More sharing options...
Doc Posted April 13, 2017 Author Share Posted April 13, 2017 Next items are #28,29,30,31 & 35 basically the con rod, yoke, bearing and connecting pin. The yoke was milled from a small block of aluminium to the right dimensions and then the holes were drilled and threaded for the connecting rod and pin. After this I used the 9.5mm slot drill to cut the 10mm slot. The con rod was next, this was basically a piece of 10mm diameter stainless steel rod with M6 threads at each end. One end has a 3mm diameter oil hole drill through to meet with an adjacent hole drill at 90° in the shaft. Then I made the con rod bearing ends. These were made from round stock which was cut to size and shaped. It was them put in the mill and the sides taken down to the correct thickness. It was next sliced in two with a slitting saw and drilled and tapped to secure together. The hole for the brass bearing was then drilled and reamed. Next the connecting pin was made out of stainless steel, and the slitting saw used to but the screwdriver groove. The above image clearly shows the oil hole to lubricate the bearing. The bearings were made next on the lathe. I made a mandrel so I could machine all sides at the same time. These are the parts I have so far made. tuckstar, +Graham and Werisit 3 Link to comment Share on other sites More sharing options...
+RonC Posted April 14, 2017 Share Posted April 14, 2017 Impressive Mick, well done Link to comment Share on other sites More sharing options...
Doc Posted April 14, 2017 Author Share Posted April 14, 2017 Thanks Ron. Item #26 the crosshead was next. This important part sits between the con rod and the yoke and guides the piston up and down. There is quite a lot of machining involved and was a pleasure to make. I made it out of mild steel instead of brass as I run out of Brass. I have loads of aluminium and steel but do lack brass. Drilling the oil hole. Below shows where the crosshead guide will screw into. Werisit 1 Link to comment Share on other sites More sharing options...
Doc Posted April 19, 2017 Author Share Posted April 19, 2017 Started building the crankshaft today. The plan was to press and loctite together for now and once I'm sure it's all in the right place I will drill, taper ream and insert taper pins to hold. Below shows the crankshaft cheeks. The cheeks were reamed either 7mm or 8 mm depending on which shaft went through it. I reamed them as a set of four to keep concentricity. The crankshafts were next these were items 16,17,18,& 19 this was a straight forward turning job, just made sure the ends were 0.004 larger then the reamed holes in the cheeks and that was enough to press the cheeks on and hold them. One end has worked loose but it will eventually be pinned so it doesn't matter. The last photo shows the crankshaft built up and the conrods and pistons connected inside their cylinders. Tweedledee, Werisit and philjay 3 Link to comment Share on other sites More sharing options...
Tweedledee Posted April 19, 2017 Share Posted April 19, 2017 You're really cracking on and doing some great workmanship Mick. Link to comment Share on other sites More sharing options...
Doc Posted May 17, 2017 Author Share Posted May 17, 2017 My lathe chuck is slightly too small to grip the billet of aluminium so I set it up on the milling machine and drilled the centre hole. I then made up an arbor and set this up in the lathe so the flywheel is running between centres, I then preceded to reduce to the correct diameter. I cut the recess on the sides and transferred the flywheel back to the milling machine. I worked out the degree positions in both the X and Y axis and set the centre position to zero. With the co-ordinates dialed in I moved the axises to the required readings and drilled the holes. I wanted the flywheel to have a key way slot so I made up my own keyway cutter with a round bar smaller than the hole for the shaft. A hole was then cut through this and a piece of tool steel placed in the hole and secured with a bolt. The tool steel was ground to the diameter of the key. I was then mounted in the chuck and the table lowered and raised a few thou at a time. It took many passes but eventually the key way was cut. Finished article. tuckstar, Werisit and Tweedledee 3 Link to comment Share on other sites More sharing options...
tuckstar Posted May 17, 2017 Share Posted May 17, 2017 Most impressive Mick. Link to comment Share on other sites More sharing options...
Tweedledee Posted May 18, 2017 Share Posted May 18, 2017 Very nice engineering. Link to comment Share on other sites More sharing options...
philjay Posted May 18, 2017 Share Posted May 18, 2017 That takes me back to my apprenticeship days ,cutting keyway. Good work Mick Link to comment Share on other sites More sharing options...
8472 Posted May 19, 2017 Share Posted May 19, 2017 Only just stumbled across this, and what an impressive project, Mick! I'd love the time and space for something like this. Every practical bloke needs a man cave. Well done, sir! Link to comment Share on other sites More sharing options...
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