Gallery, Projects and General > Project Logs
Another Paddleducks build log
spuddevans:
Well I started off today by drilling the thru-holes for attaching the steamchests and for the steam porting, and then tapping the inlet flange fixing holes.
Then it was time to use a 6mm machine reamer to clean up and finish off the piston valve bore's. Prior to this I have only used hand reamers that kinda centre themselves just using a tap wrench to turn them. However, machine reamers are a different kettle of fish ( or so I am led to believe ) they need to be accurately aligned to the bore.
This was still a new experience for me, mounting a previously drilled item back into the vice and then centering it accurately to the spindle. So this is how I did it.
I mounted a Dti in the chuck but offset it slightly on its mounting so that the spindle can be turned 360 degrees and the finger will still stay in contact with the wall of said hole. Then by sweeping it round and nudging the x and y axis until the needle stays still through a whole revolution. Then lock up the axis and :doh: watch the needle deflect, unlock axis and estimate deflection and then compensate and then re-lock. I managed to get it to within 0.005mm which I thought was ok.
This may be a little :offtopic: but I thought I'd just share a little thing I do when removing or changing tools on my little mill. I dont know if I'm the only one, but when changing tools it seems like you need about 4-5 hands, one to hold the tool in position, one to hold the spindle lock and one to tighten up the chuck, and if that is not hard enough, when it comes to remove the tool, say an end mill, you have one hand holding the spindle lock, the other is pulling on the spanner to loosen the chuck, then as soon as you loosen the chuck by what seems like a gnat's whisker, said end mill drops at the speed of light and drops on the vice chipping at least 2 of the cutting edges/teeth, whereupon the endmill will bounce onto the concrete floor. Do this a couple of times and it can get kinda expensive. So this is what I do.
Just lower the mill's head and rest the tool on a sacrificial piece of ali so that the tool cannot fall completely out of the chuck.
I'm sure that all you experienced machinests out there do this or an even better method, but this is new for me.
Anyway, back on topic.
Then I broke the whole engine assembly down to bits as soon I would need to work on the main block to drill and tap for the steam chests. That done I milled away some decorational clearances at the top of the steam chests. I still have a little shaping to do to these as can be seen from the hatched markings. This is just a rough marking, I reckon I can't go quite up to the line as it may break into the main bore of the piston valve, but this gives a rough idea of what I'd like to achieve.
Then Stefan (Spynapples) popped round and gave me a helping hand.
Together we rough cut some 2mm brass sheet for the steam chest blanking plates, then we milled them into shape, and then we milled a 3rd one to replace the rather diamond shaped one we cut earlier without properly squaring it. :bang:
Then, lacking some superglue to temporarily hold the blanking plates to the chests, we used an engineers clamp ( at least thats what I think its called ) to clamp the plate to the chest and then spotted thru to mark the holes, then we drilled both plates.
Then it was on to drilling the main block for the steam chests. With the lack of superglue spontainiously appearing in the workshop, and with the whole block and steam chest arrangement being too long to use my engineering clamps on, we mounted the assembly into the vice, carefully lining everything up while tightening up the vice. ( having an extra pair of hands was very helpful here )
But this meant that we could only spot thru on the upper mounting holes, this we did on both ends of the block. Then we drilled and tapped the 2 upper holes of both ends. Then we were able to mount the steam-chests using the top mounting holes with some M2.5 screws and then when all aligned up right we spotted thru the bottom mounting holes, and then drilled and tapped those holes.
Finally after all that we ended up with this.
That's as far as we got as the call of the wild inturupted, well the call of our stomachs anyway :lol:
Tim
arnoldb:
Good progress Tim :thumbup:
Cheers :)
bogstandard:
Tim,
Very nice indeed, you are really showing so nice machining in this post. Logical and straightforwards, with no rushing.
It is always easier with another pair of hands to assist. When I was making my engines, I had to use anything I could to help. I was working in those days with my left hand and two fingers on my right, with my right forearm swivelling from the waist, as the top of my arm was immobile. Hence superglue and other little tricks.
John
spuddevans:
Thanks Arnold and Bogs :thumbup:
--- Quote from: bogstandard on September 12, 2009, 05:33:46 PM ---Logical and straightforwards, with no rushing.
--- End quote ---
I am absolutely no good under pressure, I perform best when under absolutely no pressure at all. So when in the workshop I always try to take my time, I find its always quicker to do a task slowly than to do it quickly twice.
--- Quote ---It is always easier with another pair of hands to assist.
--- End quote ---
That is very true, and I was very grateful for Stefan's help today, especially in setting up for spotting thru the steam-chests.
--- Quote ---Hence superglue and other little tricks.
--- End quote ---
It is a great tip, using superglue, when I was woodturning a lot I used to use hot-melt-glue a lot in the same way for tempory holding.
I keep meaning to pick up some superglue, everytime I come out of the store I have everything else I didnt go in for but not the one thing I went in for :bang:
Stefan's promised me he has some that he will bring the next time he comes over. :thumbup:
Tim
ozzie46:
Looking good Tim, You will have a runner shortly I betcha.
Ron
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