Another Paddleducks build log

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spuddevans:
So I got an afternoon in the 'shop today, I started on drilling the larger hole for the actual spool valve. ( sorry no pics of this as I got a little carried away after finally getting back into the workshop )

So this is all the machining processes on the main valve block done, I blocked up the 2 little holes that transfer the steam to the ports on the engine and silver soldered them, then filed and sanded smooth.

The valve block,

Then it was on to setting up for soldering the four flanged pipes that I bent earlier, into the valve block. After a little shortening on a couple of pieces of pipe I bolted the whole to-be-soldered assembly to the main cylinder-block assembly

The eagle-eyed of you will notice that on that pic there are only 2 joints with rings of silver solder on, the reason is that I ended up re-soldering a couple of times. The 1st time two joints must not have been clean enough, and so that picture is the setup for the 1st redo.

And this is how I actually heated this 1st redo

To keep some heat off the 2 good joints I put a 1/4" piece of Ali' to deflect some heat. However, I proved to be too cautious about not re-melting the 2 good joints as when I quenched this I discovered one of the freshly soldered joints had not taken.

:bang: :bang: :bang: :bang: :bang: :bang: :bang: :bang: :bang: :bang: :bang: :bang: :bang: :bang: :bang: :bang:

So, once again I cleaned up and fluxed and soldered the one remaining joint, and thank goodness it worked.

Then it was on to the actual spool valve, I chucked up some 12mm brass rod in the ER32 chuck in the lathe

and had at it until it looked a bit like this

Parted off and lapped to the bore of the valve block with T-cut

And here's both items ( the valve block assembly has only been pickling for 20 mins here, still a fair bit of cleaning up to do )

And that's all I got done today, next will be making the front and back covers for the valve block, then it will be milling the slots in the valve spool, and then it'll be getting really close to getting it running :D :D :D

Tim

madjackghengis:

--- Quote from: spuddevans on July 28, 2009, 04:15:16 PM ---I have finally got round to making a start on my next ( Yep, I've caught it... :proj: ) project, and while tempted to do a Rocking engine, I had to stick with with my initial plan of building Bog's Paddleducks engine.

So I had previously got some materials gathered for this build, and not having any cast iron at all, but having a brass block that was itching to be reduced to a nice cylinder-shaped block, I decided to use brass for the cylinder.

Here is the raw brass block, the other dimensions are 25mm thick and 50mm high.

I then used my very expensive marking dye system and used my vernier caliper to mark out a rough shape to then transfer to my very expensive bandsaw (my right arm :lol: )

So I next ground up a tiny toolsteel for my tiny flycutter as per the Bogstandard curved profile that I read about on a thread here somewhere. This is my second attempt at grinding the curved shaped flycutter, I have a larger flycutter that doesnt cut as well as this latest attempt, practice I guess ::)

So with this newly ground up tool I am totally impressed with it. The finish on brass is soo silky smooth!!! Compare it to using a end-mill and there is just no contest. I also learnt that my X2's Z axis is made out of a very tough but flexible form of spagetti. I am intending on re-inforcing the upright column, but in the meantime I have to be mindful of taking lighter cuts.

I have an even smaller flycutter, they're so dinky.

By the way, is there an accepted method of working out what speed to set the mill at for flycutting? :scratch: ( the smaller flycutter seemed happy to run faster)

So after squaring and sizing the 4 sides I then squared off the 2 ends with a 4-flute mill.

It's amazing how the little brass chippings/shavings get everywhere (especially down the neck of my teeshirt, and they are pretty hot too :bugeye: ) My workbench was (and still is) covered with a golden snowstorm.

I then had to smooth the 2 ends with some 360grit wet+dry placed on a granite plate to try and get them to match the smooth flycutter-ed surfaces.

And here it is, the first part made to size (well within 0.02mm on 2 dimensions and dead on the 3rd :thumbup:)

That's all I got done today, not much to see so far, but it's good to be back on an engine project and I cant wait to get back into the workshop to crack on with it.

Tim

Edit: If you want to see larger versions of the pictures of this build click here

--- End quote ---
Hi Tim, with regards to speed and flycutters, it's all about surface feet per minute, or the metric equivalent. Just look up the diameter of the cut, at the edge, the material you are cutting, and the appropriate cutting speed in your Machinery's Handbook or equivalent shop data to get the feeds and speeds appropriate, and the best finish. Nice start on another interesting engine, brass always looks good. Mad Jack :headbang:

spuddevans:
Thanks for the info regarding speeds for flycutting Mad Jack :thumbup:

I got a bit more done today on the flanges for the valve body. I started up by cutting off a chunk of 22mm brass bar,

then I turned down a 10mm spigot 7mm long,

Then reversed it in the ER32 collet chuck

And turned a 1mm deep spigot sized to match the bore of the Valve body.

Then, leaving 3mm thickness on the flange I was parting off, I parted it off. Then it was on to the top flange. I turned another 1mm deep spigot to fit the bore, drilled a 4mm hole all the way through, then bored a 6mm wide by 0.9mm ( ok, mine turned out to be 0.88mm but lets not split hairs ) recess which is for a sealing O-ring.

Here are the pair of flanges ready to have the mounting holes transferred from the main valve block, then drilled and the back flange tapped, that will be the next job.

the other side showing the recess

That's all for today,

Tim

Ray:
Tim, I notice you and others use a radial surface on your flycutter tool. Does it have any angles (rake) or both sides and top just flat? I tried tosharpen my cutter like that, all flat sides and top. It just thuds over the surface leaving big dents. Any tips or advise will be appreciated. Very nice build. Ray

spuddevans:
Hi Ray, I sharpen my flycutter using the method that Bog's showed in This thread

It does seem that the rake is important to getting a good finish and having a reasonably durable edge for the tool. My 1st attempts at grinding a flycutter did not work too good, but by sticking at it and taking note of what others said, and especially that post of Bog's, I managed to get going ok. Now I just wipe the face of the tool on an oilstone a few times before using it and that seems to keep it sharp.

I find that I can get a lovely silky smooth finish on both brass and Ali', I've had some mixed experiences with cast iron, but I think I was trying to run the spindle speed far too fast. That's what I love about flycutting brass, it accepts a higher speed.

Hope this helps,

Tim

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