Del Greco | 23/09/2020 10:12:56 |
35 forum posts 13 photos | Looking great. This was my first engine build and it was so satisfying seeing it move for the first time. Looking forward to seeing more. D |
Dr_GMJN | 26/09/2020 16:43:22 |
694 forum posts | Posted by Del Greco on 23/09/2020 10:12:56:
Looking great. This was my first engine build and it was so satisfying seeing it move for the first time. Looking forward to seeing more. D Thanks! |
Dr_GMJN | 26/09/2020 16:44:17 |
694 forum posts | Not quite finished the eccentric strap yet - I’ve got to drill the oil hole, but can’t figure out how to do it: |
JasonB | 26/09/2020 16:58:52 |
![]() Moderator 19504 forum posts 2131 photos 1 articles | The ideal thing to do the oil hole with is a long series ctr drill, I have an 1/8" x 3" long one which would be just right. Failing that you can do it at a slight angle to get clearance or make a simple extension for an existing ctr drill by drilling a hole in some rod and using a drop of loctite to retain it. |
Dr_GMJN | 26/09/2020 18:34:49 |
694 forum posts | Posted by JasonB on 26/09/2020 16:58:52:
The ideal thing to do the oil hole with is a long series ctr drill, I have an 1/8" x 3" long one which would be just right. Failing that you can do it at a slight angle to get clearance or make a simple extension for an existing ctr drill by drilling a hole in some rod and using a drop of loctite to retain it. Thanks, I'll try and get hold of a long series center drill then. The smallest one I have only just fits, making sleeving it impossible. Re. the eccentric strap locating bolt - even though I've got clearance on teh groove, it still picks up occasionally. I wonder if it would be better made of brass, rather than steel-on-steel as it is now. It seems pretty smooth without the pin in place. Cheers. |
JasonB | 26/09/2020 18:37:53 |
![]() Moderator 19504 forum posts 2131 photos 1 articles | It's unlikely to pick up and gall so I would leave as it is, a small amount of play won't hurt. |
Dr_GMJN | 29/09/2020 08:23:14 |
694 forum posts | Today I re-visited the cylinder, and made some progress with the steam ports. |
JasonB | 29/09/2020 10:04:55 |
![]() Moderator 19504 forum posts 2131 photos 1 articles | This is one of the few occasions when I would suggest drilling the cleading first and then spotting through the hole positions onto the cylinder or simply clamp the cleading around the cylinder and drill tapping size right though both before tapping the casting and opening up the other holes. |
Dr_GMJN | 29/09/2020 10:24:39 |
694 forum posts | Thanks Jason - yes, only this morning I experimented by wrapping the cladding around the cylinder to do just that - hold it in place and drill pilot holes before springing the cladding off and drilling/tapping as appropriate. Then secure through the just tapped holes, re-orientate, and repeat the process. Didn't you say to use a smaller drill than tapping diameter where it breaks through to the cylinder for the drain cocks though - about 2mm IIRC? I want to do this before lapping, so that I can then make the piston assembly. I need to get it in the right order... Of course I also need to mill the O/D of the casting a bit using the rod-through-the-hole method you suggested a long time ago, in order to get the cladding to be a perfect fit under the cylinder cap overhangs. I also want it a flush fit to the valve chest - I machined that at the time to have the correct step. |
Dr_GMJN | 29/09/2020 21:31:30 |
694 forum posts | So today I tried to mill the outer cylinder concentric with the upper cylinder, using a method suggested here on the forum. This involved positioning a rod in the bore, putting it in the vice and milling a series of flats all around: |
JasonB | 30/09/2020 06:55:33 |
![]() Moderator 19504 forum posts 2131 photos 1 articles | Yes you can use 1/16" or 1.5mm holes to drill the last couple of mm. It is anodised |
Dr_GMJN | 30/09/2020 07:41:49 |
694 forum posts | Ok. Are the holes in the cladding for the exhaust and drain cocks meant to fit around the parts? The exhaust in particular would appear to want to distort the cladding when tightened, because it’s at an angle to the surface. Also the drain cocks fit to a curved surface - should the seats be spot-faced and clearance holes made? Thanks. |
geoff walker 1 | 30/09/2020 11:38:14 |
438 forum posts 168 photos | I think you would to cut a channel for the exhaust port. If you try to distort the cladding when you tighten up the exhaust the cladding will just buckle. Is the cladding aluminium? If yes I am left wondering why the anodising did not crack when you formed the curve. What gauge is it, can you put a Mike on it to find out, I'd be interested to know. Also can you give more details about how you formed the curve. Was it as simple as you make sound to get such a neat curve, no clamping involved? Thanks geoff. Great work doc, once again I admire your attention to detail |
Dr_GMJN | 30/09/2020 12:49:47 |
694 forum posts | Posted by geoff walker 1 on 30/09/2020 11:38:14:
I think you would to cut a channel for the exhaust port. If you try to distort the cladding when you tighten up the exhaust the cladding will just buckle. Is the cladding aluminium? If yes I am left wondering why the anodising did not crack when you formed the curve. What gauge is it, can you put a Mike on it to find out, I'd be interested to know. Also can you give more details about how you formed the curve. Was it as simple as you make sound to get such a neat curve, no clamping involved? Thanks geoff. Great work doc, once again I admire your attention to detail
Cheers Geoff, Yes, it's aluminium, about 0.5 mm thick. The coating is extremely thin, to the extent that it fades away in certain areas, so it's unlikely to crack. Initially I just wrapped it around the casting by hand, forming it around the block with my thumbs, while making sure it wasn't skewed. There was some spring-back, so it needed over-bending slightly. I found that gently forming it around the socket (again by hand) eventually gave it the correct radius. Obviously I didn't go further than the straight edges where it tangents back to the valve block. The drilling may, or may not work out, but I kind of see it as a challenge to get it fitted properly without damaging the coating... |
JasonB | 30/09/2020 12:56:40 |
![]() Moderator 19504 forum posts 2131 photos 1 articles | A step drill is handy for cutting clearance holes for drain cocks |
Dominic Bramley | 30/09/2020 12:59:20 |
31 forum posts | I finished my 10V earlier this year, and the cladding was the only part I managed to scrap. My mistake was to drill the holes as per the dimensions on the drawing and not having the presence of mind to remember that the (already drilled) exhaust port on the cylinder was not dimensioned. Still - at least it was an easy decision to chuck it in the bin when the holes didn't line up! Second time I measured from the job and using a 1/8 BMS drilling jig, as per Harold Hall's instructions, produced nice clean holes. For the drain cocks I spotted the holes and drilled clearance. For the exhaust port I drilled 1/4 and turned the exhaust pipe out of hex stock to produce a tube with a nut part way along it - just a little further up from the end of the thread. The exhaust pipe could then be screwed into the cylinder and tightened up without the nut crushing the cladding. Not sure if this is the "correct" solution - but looks Ok to me.
Dom
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Dr_GMJN | 30/09/2020 15:27:04 |
694 forum posts | Thanks both - I’ll get a step drill from Arc. Dom - I might steal your idea for the exhaust. I considered doing something similar, but with some shallow flats milled on some brass tube, with the end threaded. Could you by any chance post a picture of your 10v? Thanks.
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Dominic Bramley | 30/09/2020 16:03:42 |
31 forum posts | I don't have any pictures to hand just now - but here is a video of its first run on steam that gives a pretty good view of the exhaust. I threaded the other end of the tube also to connect to the elbow connector. https://www.youtube.com/watch?v=xCclavQAQjA Very satisfying when they run for the first time! It has run in since and can run quite slowly now. The boiler is the ME vertical boiler which was serialised in the magazine last year and was also fun to make! Regards Dom Edited By Dominic Bramley on 30/09/2020 16:04:29 |
Dr_GMJN | 30/09/2020 19:44:28 |
694 forum posts | Posted by Dominic Bramley on 30/09/2020 16:03:42:
I don't have any pictures to hand just now - but here is a video of its first run on steam that gives a pretty good view of the exhaust. I threaded the other end of the tube also to connect to the elbow connector. Very satisfying when they run for the first time! It has run in since and can run quite slowly now. The boiler is the ME vertical boiler which was serialised in the magazine last year and was also fun to make! Regards Dom Edited By Dominic Bramley on 30/09/2020 16:04:29
Thanks Dom - it looks like a very nice 10V build, and setup with the boiler too. |
Dr_GMJN | 30/09/2020 19:45:46 |
694 forum posts | Eccentric strap. Started by mounting the stamping into the 4-jaw chuck, using a tight fitting spigot in the tailstock chuck as a guide: |
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