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Post by Shawki Shlemon on Oct 18, 2012 9:09:00 GMT
Pete , I made one of these 30 years ago and still use it , its great . Mine is a little different , instead of using a round pointed rod , I used a 1/4" square bar ( mine is lathe tool ) chamferd at the end towards the bottom ,the bottom face is the height required , I find that easy to check . I guess they both will do the same job. ;D
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peteh
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Post by peteh on Oct 18, 2012 9:57:57 GMT
hi Shawki, The pointer is flat on the under side so I have a flat to work to.
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Smifffy
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Post by Smifffy on Oct 20, 2012 9:37:31 GMT
Very nice. Mine is much simpler. The tool is adjusted till it touches the underside of the brass tab. Smifffy Attachments:
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Post by peteh on Oct 20, 2012 12:42:38 GMT
Well the pistons have been machined to fit the cylinders - a very satisfactory 'pop' from eachwhen pulled out  Next task is the covers - front and back. |
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Post by peteh on Oct 20, 2012 14:54:39 GMT
I've just been drawing up the cylinder covers, modified for 6 bolts instead of 4. There is very little meat in some areas. The walls of the piston gland recess is only 1/32 thick on the outer edge of the lug and also to the guide bar holes. Is this really enough? Note that this is as the dimensions work out in the plans an is unaffected by wether 4 or 6 bolts are used. The section/plans shows substantially more. Might have to check out to true plans in the shed rather than that in ME. Attachments:
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Post by peteh on Oct 21, 2012 14:10:59 GMT
Well the first cylinder cover is almost finished, just the bolt holes to go. I think I spent more time today making jigs than producing the actual part. I assume I just have to file down the part of the cover which cannot be turned due to the guide bar support /gland section (herein now known as the 'big lumpy bit ) being in the way. The second cover has beeen started, with the locating 'spigot'? turned to size and the rear running true and the 5/32 hole drilled through. Looks like it's time to learn how to use a rotary table. As is usual, having a combination machine I try to do all of the turning before converting to mill mode (or vice versa as the job dictates) Attachments:
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Post by doubletop on Oct 22, 2012 6:41:34 GMT
Pete
It looks like you've had a burst of activity and all seems to be going well for you.
Can't be far off running on air. I'd guess we're looking at a matter of weeks now.
regards
Pete
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Post by peteh on Oct 22, 2012 7:47:51 GMT
I think at the speed I go it will be nearer Christmas  Still got the front covers to do and finish off the rear covers. Also a bit of plumbing etc but there is definately progress. As implied in the earlier post - I will be going for 6 8BA bolts rather than the four 6BA. I have just inherited a portable aircon which will make the shed a more habitable place in the summer - just got to be able to afford the electricity now! Unfortunately I won't be doing too much more this week as my wife (Marion) and I are going down to Nannup for a rogaine, leaving Friday and back on Sunday. The great thing about rogaines is that I get to eat lots of chocolate (I'm a diabetic) just to keep my sugars up |
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Post by Shawki Shlemon on Oct 22, 2012 8:23:27 GMT
Things looks very nice , it looks that you are certainly progressing better than I .Looking forward to see it running on air as a step to running on steam. all the best mate .
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Post by peteh on Oct 25, 2012 14:00:46 GMT
quick update - managed a couple of hours tonight and have all of the turning finished on all four cylinder covers. Had one problem when parting off a front cover from the spigot of the casting - the parting tool grabbed and bent the piece, marking the face of the cover. I have managed to remove all but a little mark, although I am now 0.1mm under size on this cover. Photos tomorrow if I have time before heading south for our rogaine |
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Post by peteh on Oct 26, 2012 6:58:14 GMT
couple of photos showing the covers. The drilling remains to be done, plus drill and tapping of the cylinders. Attachments:
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Post by peteh on Oct 26, 2012 6:59:08 GMT
Hopefully will be able to check in on Sunday night when back from the bush Attachments:
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Post by doubletop on Oct 29, 2012 9:09:24 GMT
Pete
I'm still following along. Are you back yet?
Pete
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Post by peteh on Oct 29, 2012 11:54:46 GMT
Back from down south but suffering - 18Km in 9 hours, but scored our personal best ever - 1120 points so have finally broken the 1000 barrier Havn't been back in the shed yet as the legs are still killing me! |
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Post by peteh on Nov 3, 2012 13:38:34 GMT
Spent a good few hours shedding today. It was a case of making a Dial Indicator holder that is held in the tool post. A relatively quick and dirty job. Take a bit of 10mm square mild steel, cut part way through, bend 90 degrees and then weld. Drill for the instrument stem and saw through and then drill and tap the clamp bolt hole. The bronze clamp bolt is made from an old keel bolt from the turn of the 1900's (the boat was launched in 1908 so I'm told) There was discolouration for about a millimetre depth. Once made I put a 2MT centre in the chuck and set my top slide over so that I could traverse along the centre without the indicator changing this allowing me to .... Attachments:
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Post by peteh on Nov 3, 2012 13:46:28 GMT
.. turn a 2MT taper on the base of my cover holding jig which centralizes the covers to the rotary table. This method worked great and was reasonably quick to get to the correct setting. According to tables I should have had an angle of around 1 1/2 degrees but my scale showed less than 1 degree! Tomorrow will involve boring out the other end of the jig to accommadate the covers, and then hopefully drilling the bolt holes. Attachments:
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Post by peteh on Nov 4, 2012 12:25:30 GMT
Finished the jig this morning. Here's the top view - after use Attachments:
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Post by peteh on Nov 4, 2012 12:35:16 GMT
Ran into a small problem after mounting the rotary table on the mill table - after adding the jig and cover there was only around 10mm clearance left under the drill chuck. This is another hassle of the combination machine. Setting up the table central to the mill had to be done before adding the jig, the table then offset for the PCD and then the jig and covers added and clamped. Due to the small clearance I had to change clamp positions as I rotated the table. However at the end of the day I have all covers drilled (tapping size), ready to transfer the hole positions onto the cylinders. Problem - I wont have room under the mill for both the rotary table AND the cylinder! I have plenty of room under my new drill but no easy way of offseting the table accurately. Other than setting up and drilling each hole individually what are my options? I guess a traverse vice (is that the right term) is an expensive option for just one set of holes! Attachments:
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Post by peteh on Nov 5, 2012 0:59:55 GMT
For traverse vice read compound table!
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Post by doubletop on Nov 5, 2012 9:56:24 GMT
................ Other than setting up and drilling each hole individually what are my options? ........... Pete First thought was the jig doesn't need to be so tall but you've used it OK so that's not so critical an issue now. How about some photos of your setup it may trigger some thoughts from people? Especially how you mount jobs in the milling mode. Pete |
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Next task is the covers - front and back.
Still got the front covers to do and finish off the rear covers. Also a bit of plumbing etc but there is definately progress. As implied in the earlier post - I will be going for 6 8BA bolts rather than the four 6BA. 
