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Tooling & Machines / Re: A small dividing head
« Last post by RReid on Today at 12:31:41 AM »
Well, it's not quite a dividing head yet, I still need to make a division plate and the attendant stop pin, etc. But with a simple utilitarian crank, it can now be used as a rotary table. At least I think so, I haven't had a chance yet to actually prove that. :thinking:






Since the Taig spindle I used has a “bearing pre-load nut” at the far end, which I retained but don't have any bearings to pre-load, I think I can use that nut as an effective brake, eliminating the need for a separate one. You can see it in this last picture.
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Chatterbox / Re: Gardening
« Last post by crueby on Today at 12:15:44 AM »
A frog sitting sentinel in my allotment pond ..I don't know how he got there though ??
...and some Heritage Seed Library items    Victorian Purple podded ..peas...and it has started to rain in Norridge !!

Willy
Thats not a normal frog, thats a rare amphibious shop elf, there to help on your turbine build!!
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Chatterbox / Re: Gardening
« Last post by steam guy willy on Today at 12:09:41 AM »
A frog sitting sentinel in my allotment pond ..I don't know how he got there though ??
...and some Heritage Seed Library items    Victorian Purple podded ..peas...and it has started to rain in Norridge !!

Willy
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Your Own Design / Re: Chris's Holly Pumping Engine Build
« Last post by crueby on June 16, 2021, 11:27:11 PM »
Some more done on the blocks with the bosses around the flat section - started the arc work with the small end mill, back and forth between cutting the arc and taking the sides of the bosses down vertically.


then switched to the larger cutter to take the ends down close - as mentioned before, the ends will be finished up with the rotab horizontal to flare the ends to match the existing plates.

Fiddly work, taking lots of breaks between parts to keep the concentration up with all the rotary etch-a-sketching!
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Your Own Design / Re: Chris's Holly Pumping Engine Build
« Last post by crueby on June 16, 2021, 11:23:02 PM »
Great development. Some masterful skills in evidence here.

Good job that elf wasn't sitting having lunch on a girder 900 feet above the streets of Manhattan when you cut it though!
:Lol:
Just had flashback to the old movies like that - Harold Lloyd, etc. !
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Your Own Design / Re: Chris's Holly Pumping Engine Build
« Last post by gary.a.ayres on June 16, 2021, 11:08:42 PM »
Great development. Some masterful skills in evidence here.

Good job that elf wasn't sitting having lunch on a girder 900 feet above the streets of Manhattan when you cut it though!
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Your Own Design / Re: A Simple Uniflow Engine
« Last post by gary.a.ayres on June 16, 2021, 11:01:03 PM »
Yes!

Cheers, Chris!

 :cheers:
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Your Own Design / Re: A Simple Uniflow Engine
« Last post by crueby on June 16, 2021, 10:59:40 PM »
Great journey so far, getting close!!   :popcorn: :popcorn: :popcorn:
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Engine Ancillaries / Re: Fuel injection systems
« Last post by Admiral_dk on June 16, 2021, 10:46:03 PM »
Re: Lap wear - as far as I remember it's the harder of the two materials that will be worn when you use a lap ... Why - the grinding particles imbed themselves into the softer of the two materials (if it can), and therefor cuts the hard material ....
So I guess that if both materials are hard it becomes unpredictable where the cutting happens ....
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Your Own Design / Re: A Simple Uniflow Engine
« Last post by gary.a.ayres on June 16, 2021, 10:31:20 PM »
It seemed to me that the big end needed an oil hole for lubrication of the bearing. I hadn't sufficiently taken this into account at the design stage so I was left with very few options for an oil hole that wouldn't foul either the threaded holes for the screws that hold the bearing cap in place or the probably over-deep hole into which the connecting rod is threaded:



My solution was to drill the oil hole at an angle from a point very close to the bearing cap screw hole through into the bearing. Here I am just about to make a start with a centre drill before swapping to a twist drill:



After centre drilling I started with a reasonably wide drill to create a small oil reservoir at the top end of the hole, then I changed to a much smaller drill and drilled though to the bearing surface. In practical terms this appears to have worked ok, but I am not happy with the way that the oil hole clashes with the cap screw hole:



It's not a great look but as I say I was limited for choice. The oil hole emerges quite pleasingly on the inside of the bearing, though:



Initial testing would suggest that the flow of oil into the bearing is not too fast. If in practice it turns out to be too slow, the hole can easily be opened up a little.

Note the weeds growing back between the slabs of my back yard after a recent weeding. Building engines is a more attractive pastime to me than weeding is.

That done, it was time to mill flats on the crankshaft to seat the flat-nosed grub screws which secure the flywheel and pulleys. I had already done similar before I changed the overall layout of the engine so there are now some redundant flats on the shaft as well as those which are in use. I don't think that's an issue, though. Marking out the positions of the flats with the shaft in situ:



Milling the flats (I find 0.5mm depth to be about right on this 12mm shaft):



These jobs done, I completely dismantled the whole engine:



On reassembly, each part was cleaned as I added it. For the aluminium, I was not seeking a mirror finish, but more of a satin look, so I used steel wool then wiped with French 'alcool ŕ bruler' (basically methylated spirits). There are still some marks on the larger areas - a scratch here and there, even a couple of scribe lines. These do not bother me:



I also deburred the decorative holes in the frame where required.

The cast iron parts and the steel flywheel were also given the steel wool treatment, but the bronze collars and bearings and the brass pulley were spruced up with 'Autosol' metal polish:



Screws and other small parts were given a soak in the alcool ŕ bruler and brushed clean.

The newly cleaned-up engine was reassembled yet again, and this build is nearing its end. I shall post a couple of pictures of it sometime over the next day or two, along with some details of overall weight and dimensions.

All that remains now is to finish the oak base and mount the engine on it.

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