Author Topic: Simple wobbler  (Read 1743 times)

Offline PaulR

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Re: Simple wobbler
« Reply #15 on: January 26, 2025, 04:03:16 PM »
Made the 'big' ends today. They're threaded 3mm to fit the piston rods with a 2.5mm hole for the crank pin. The first one went great and was half way through making the second when I realised I'd picked up the wrong piece of stock. Oh how I laughed. No matter, the second one was soon sorted and they fit ok. I think left enough room for them to move without rubbing up against each other but they'll look better with rounded ends so next up will be some filing buttons.


Offline PaulR

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Re: Simple wobbler
« Reply #16 on: January 26, 2025, 08:30:08 PM »
Rounded off the big ends but still need to do some fine filing. Hooked up one of the rods to check alignment but need to cut them to length as well.



Offline redhouseluv

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Re: Simple wobbler
« Reply #17 on: January 26, 2025, 09:22:43 PM »
I had one of those Sieg lathes which I modded with several of the known improvements, sadly sold it when I was limited for space  :(

Looking good, keep going, looking forward to seeing the result  :popcorn:



Best regards

Sanjay

Offline PaulR

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Re: Simple wobbler
« Reply #18 on: January 27, 2025, 10:03:27 AM »
I had one of those Sieg lathes which I modded with several of the known improvements, sadly sold it when I was limited for space  :(

Looking good, keep going, looking forward to seeing the result  :popcorn:
Cheers Sanjay. I've got a list of mods and tools I'd like to make in time but most involve extra expenditure which isn't on the cards at the minute having just created an entire workshop! For now I've just taken off the annoying perspex chuck cover and the swarf collector at the back which really gets in the way when fiddling with the 4-jaw.

Offline PaulR

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Re: Simple wobbler
« Reply #19 on: January 27, 2025, 05:08:20 PM »
Rods attached and it turns over fairly smoothly by hand although I need to get the rod lengths equal (I just eyeballed them). Next, drilling six holes in each port block to get the inlet and exhaust connections where I want them.

Offline PaulR

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Re: Simple wobbler
« Reply #20 on: January 29, 2025, 07:41:55 AM »
A small disaster struck while drilling through one of the port blocks - the solder parted company and forced the 2mm drill to one side meaning a slightly misplaced port but probably won't make much difference in practice. So much for me saying how surprised I was at how strong the sweated bond seemed! When I first looked at the plan on which this engine is roughly based I thought the port block arrangement was a bit iffy and they have proved the most troublesome parts. I'll probably build another similar engine after this one (if it runs!) but with a better arrangement for those blocks.

Offline PaulR

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Re: Simple wobbler
« Reply #21 on: January 29, 2025, 08:57:49 PM »
Refitted the errant port block and finished drilling the holes which was quite tedious. Made the four in/out connectors which are going to have to be fixed with Loctite as I dare not risk tapping or soldering. I'm only planning to run this on air so shouldn't be a biggie. Ordinarily I'd fit some threaded plugs to the surplus holes and file them invisible but again, threading these blocks four times over will risk dislodging them so I plan to make some little steel caps and Loctite those in place too - at least they'll match the cylinder end caps. I've never made an engine with soft solder and so much Loctite before and it makes me feel a bit queasy - the next version will be screws and silver solder all 'round!


Offline PaulR

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Re: Simple wobbler
« Reply #22 on: January 30, 2025, 08:23:26 PM »
Made the fiddly little end caps and stuck it all together. The only thing wanting now is a flywheel because it probably won't move a micron without one! Suppose I'll have to bite the bullet and buy some 2" steel.


Offline crueby

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Re: Simple wobbler
« Reply #23 on: January 30, 2025, 08:48:29 PM »
While waiting for the steel, if you have a drill chuck handy, they make nice temporary flywheels (have done that a number of times!)
 :popcorn:

Offline PaulR

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Re: Simple wobbler
« Reply #24 on: January 30, 2025, 09:15:41 PM »
While waiting for the steel, if you have a drill chuck handy, they make nice temporary flywheels (have done that a number of times!)
 :popcorn:
Crafty, I like it! Yes I have a small one that came with the lathe. The compressor is up and running but I'm still waiting for tube to arrive so it'll be a few days yet before I find out it doesn't run  :ROFL:

Offline PaulR

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Re: Simple wobbler
« Reply #25 on: February 01, 2025, 03:33:44 PM »
Put the bits together today and screwed it to some scrap wood, during which one of the pivot pins came adrift. Annoying and makes me like Loctite even less. Took a chance and soft soldered it back in place (which explains the slightly different colour of the left cylinder!). Seemed to work ok although a little tightness was causing the cylinder to lift a little when down the far end. Tightening the nut on the pivot, plenty of oil and endless spinning by hand using the Crueby Flywheel (TM) seems to have sorted it... it'll spin for a few revolutions without any looseness. I'll continue to tart things up while waiting for the flywheel and compressor bits (an ebay page reoload reset a dropdown menu and I ended up buying a 3/16 fitting instead of 1/4").

I'm afraid there haven't been a lot of machining photos in this build log but I guess photo's of turning down a bit of brass, selfies of me filing, or recordings of me cursing Loctite isn't going to impress or entertain anyone :ROFL: Hopefully there won't be much more to put up with!

Offline PaulR

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Re: Simple wobbler
« Reply #26 on: February 06, 2025, 09:18:51 PM »
Still waiting for the right compressor fitting to arrive (don't ask) I decided to find something to make a flywheel. One of my other interests is archaeology and almost a year ago to the day I unearthed a large tapered plug while excavating the site of a steam-powered well pump. Today I decided to chop it up and make a flywheel our of one end - it looks like it has a steel piece in the middle probably where the handle was attached, the other end has a badly corroded cast iron part. After some hacksawing I ended up with a lump that I could hold in the three jaw despite the slight taper. What I didn't bank on was how hard the corrosion products were - it took me an hour and forty minutes of facing cuts of a few thou because the corrosion flattened the HSS tool like it was putty! I must have reground about 1/4" off the tool by the end.

Just as I removed the last bit of corrosion a hole appeared at centre so I guess I've reached the steel bit. Hopefully the other side will be much easier. I plan to either leave the steel where it is or plug the hole  with brass if it comes free. Fingers crossed I'll have a usable flywheel by the time the compressor fitting arrives.

Offline redhouseluv

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Re: Simple wobbler
« Reply #27 on: February 06, 2025, 11:30:07 PM »
Nice bit of recycling!

Now that's what I call rusted  ;D
Best regards

Sanjay

 

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