Gallery, Projects and General > Project Logs
Twin Cylinder Steam Engine
Darren:
A little shop time this evening, not much so progress a little slow tonight.
Having now re-set my mill it was time to get back to making the little brass pillow blocks.
The source of material was to be cut from this 1 3/4 x 1/2" bar
All the sides done now for the ends
All done, I left them 0.1mm oversize to allow further machining and for possible vice/lathe jaw marks to be removed in the final clean up/polishing stage.
Next job was to drill the crankshaft holes. Notice I have made and adjustment to my vice stop. I found that positioning such small pieces at one end of the vice was not the best way to go about things. Mainly because there is no bottom support in this area and when clamping and pushing down on the part things could go horribly wrong.
So I added a 6mm brass screw (with the end polished) and locking knurled thumb nut. This really improved the situation.
Also notice I have marked the datum surfaces. The bottom and one side. This is because the crank hole is not central and we need to be aware of this in further operations for correct orientation.
Holes were center drilled and then drilled to 4.5mm.
And this is where I finished off for tonight. A little further on.... :)
Darren:
I forgot to say, when suitable I like to add a little
"what have I learnt from this episode"..... :)
Cutting four little blocks and then trying to machine them all to the same size was a little difficult. Not impossible as you can see. But I believe this type of task would be easier if one long strip was machined up first and then cut into the four lengths required. Followed by machining to length.
It seems that when four individual blocks are put in the vice at the same time they move by different amounts when the vice is tightened. So they do not end up the same size after machining.
It's slight, but it did exist. I got there in the end with a little dose of patience.
:ddb:
Darren:
John, Can I ask you for a little bit of advice please..
I need to make an order for some small screws, typically in the tiny range of 2.5mm. I can look through your logs and estimate what's required but for small engineering I'd also like to order for the future at the same time.
Could you give a general list of what you find handy to keep on the shelf? Only the small stuff, say up to 4mm.
I understand you order from here http://microscrews.easywebstore.co.uk/default.aspx
Darren:
And so we proceed with the pillow blocks a little more this evening .... :ddb:
Oil hole marked up, center drilled, drilled out to 2.5mm and finally tapped 3mm.
I had to hold two together because my make shift parallel "a large HSS lathe tool" was too wide for just the one block.
All four done. Here I'm lapping them all true to size on all sides to each other. I have mounted all four onto a 4.9mm drill bit to line up the crankshaft bores. (at this stage they are drilled to 4.9mm as I will ream them to size later) By lapping not only will they all be the same size externally they will also have their bores in a perfect line when mounted.
Note the use of the now famous lathe bit clamped to the bench. This is to ensure that none of the pieces tries to turn. Give em half the chance and they will...!! It also ensures a square angle is kept between sides.
All done
I'd previously pop marked the bases to help with orientation during each machining process. Just checking they are still there.
Drilling the base mounting holes
All done, I don't currently have a 2.5mm tap, one is on its way so tapping can wait till later.
Now onto some profiling purely for aesthetics. I'm using a semi ball nosed carbide cutter. Tough stuff this brass ya know...!!
OK, it was the only cutter I have with any sort of small radius.....
And the other side
Off to the mini lathe to form the boss's, I chose 1mm for looks.
All done on both sides,
My missus called them "little cameras"
All they need now is the bases tapped and a general de-bur followed by a final clean up.
sbwhart:
Looking good Darren :thumbup:
Stew
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