Economy Model

[mhirst121]

Well after lurking for a while I think it is about time I started adding to the excellent build logs on the site. A couple of years ago I bought an Economy kit from engineers emporium at the Harrogate show, this will be the next in line.
The kit contains aluminium castings for the base, hopper/cylinder assy, and the crank caps. The cast iron parts are the flywheels, head, rocker aswell as cast iron bar for the liner and the piston. I have had a look through the drawings and have found a few mistakes already, which considering the time this model has been about I feel they should have been sorted, but I will be checking everything just to make sure and modifying where I feel the need.
I started with the base, squaring up the bottom first then measuring to see if everything fits!! When checking the measurements I found that the saddles for the crank bearings were already undersize before touching them with a tool, so this will be made to my size and the bushes adjusted accordingly.
Well I suppose you`d all like some pictures so here goes. I have to say that this engine is about the largest I can handle so some of the set-ups may make you cringe a bit, but as long as they work and the engine gets finished, who cares.

The base was set up on the mill and the cylinder mounting face machined



Crank saddles machined to size, taking into account the lack of material, and the holes drilled for the caps and the cylinder mountings.





The bearing caps were in one length so they were squared up, holes drilled and split once complete.





Holes were all tapped M6 in the base and the caps fit.





The base was then swung round on the mill to bore the holes for the crank bearings, the head was also swung 90 degrees to do this. This was the first drawing mistake I spotted, the caps called for a 12mm radius for the bearing and the base for a 13mm radius. I don`t think they should be different so I bored it out to 26mm.







So I will leave the base at this point till I get the cylinder done.
Cheers,
MartinH

[mhirst121]

This is how I would like it to look when it is finished, only done in light blue as a Jeager engine.



Cheers,
MartinH

[b.lindsey]

Nice start on the new project Martin and I love the cart. That would look great with your Economy sitting atop it!

Bill

[jadge]

Martin: I got about three quarters of the way through an Economy engine before I moved onto my traction engines. I can't remember when I started but it must be 10+ years ago. The first base casting I had was wonky, and was changed with bad grace. As you have found the crankshaft bearing lugs are too narrow. I did the same in machining them undersize and increasing the thickness of the bearings to compensate.

I got separate bearing cap castings, so it looks like that has changed within the kit. I binned the flame cut connecting rod blank as it was thinner than the drawing called for. I machined my connecting rod from a lump of hot rolled. I also binned the light alloy valve actuating arms.

I will post a picture in the morning.

Andrew

[Graham G]

Hi there Andrew, I just might follow along on this build if thats ok.
Cheers Graham

[Dave Otto]

Cool, another engine build to follow along with.

Thanks for posting.

Dave

[Jasonb]

Martin, I have a lot of photos of a Galloway crosscut saw very similar to the above if they are of use PM me your email.

Will you drive it direct off the fixed engine pully or add a cone clutch pully?

J

[jadge]

Martin: As promised here is a picture of the crankshaft end of my Economy:



I must have machined the inside of the engine base with a big horizontal side and face cutter, as the machined surface goes down as far as possible. It can be seen that the bearings are wider on the outside than the inside to compensate for the undersize casting.

The radius on the inside of the bearing caps isn't even dimensioned on my drawings, so I suppose a number, even if it is wrong, is progress. There are a lot scribbles (by me) on my drawings, so I think there might have been some issues with the location of the cylinder block?

Andrew

Graham: Fine by me if you tag along, but it's not actually my build thread!

[mhirst121]

Thanks for that Andrew, I think there could be more problems ahead. You would think they would have altered the patterns to improve the situation!!
Jason, I will get back to you when I make a final decision if that's OK. The ones I have looked at just have a slack belt with a weighted pulley to tension it, but a clutch may be better.
Cheers
MartinH

[mhirst121]

Well I have set to work on the cylinder over the last couple of days. Surprise, surprise a few more faults turned up with the castings which I will document against the relevant pictures.

The block was set up in the lathe to machine the bore ready for the liner. I know it looks a little precarious, but it did have a good hold of the part and I machined it at very low speed and feed to avoid any mishaps or chatter. The block is only aluminium and with light cuts it all went ok.







Once complete it was over to the mill to square up the outer details. I made up a plug to fit in the bore with a centre so that I could use the rotary table to hold the part and index it as required.



The side pad was taken to size first and then the position for the holes for the dummy magneto were measured out. Heres the first of todays problems, the pad is in totally the wrong position on the casting to drill it as per the drawings!!!! If you look at the first picture below this shows where the first hole should be according to the drawing.



So to overcome this I had to move the bolt holes across 10mm to get them onto the pad. I checked with the mating part drawings and I can alter the mounting holes in the magneto bracket to suit. Drawings have been scribbled on to help remind me later. The hole for the spark plug was drilled and a pocket machined to get a flat seating face.



The rotary table was then turned through 90 degrees to machine the base for mounting the cylinder. Heres the next problem, there is not enough material on the bottom to be able to machine it to the required size on the drawing, half the area did not take a cut off. So once again I have had to take an extra 1mm off this and will have to fit a spacer under it when mounting to the base. Note added to drawing, at this rate there will be more of my work on the drawings than what was originally on them. The holes were then drilled in the correct, I hope, place.





And here it is mounted to the base.



Cheers for now,
MartinH

[b.lindsey]

Martin, the early pictures in the thread are missing now, did you perhaps change their location on the photo hosting site?  If so it breaks the links  and that looks like what may have happened. Very much enjoying your build log though, just want to make sure it is all available to others.

Bill

[mhirst121]

Thanks for the heads up on that Bill, I had moved them into there own folder, are they ok now? 

MartinH

[Jasonb]

All look OK to me now.

I wonder if some of these size issues are due to teh pattern originally having been meant for iron castings and the ali is shrinking more?

Martin, I just realised you are the man with the pump, did you ever complete the set of drawings? I have just bought a set of castings for a VJ Monitor and will be needing to make a suitable pump.

J

[mhirst121]

Yes Jason I did the pump. I never got round to finishing off the drawings as I could not get my head round the solidworks program and how to use it, it was just a friends I was using and only got it to play with now and again.. If anyone could finish the drawings, from my fag packet drawings, I would post them up here for anyone to use as it is a really nice thing when finished. Once again sorry about that but I am more of a doer than designer, I make the parts to fit in a way I think looks right.
This is the one you mean Jason?



Cheers,
MartinH

[Jasonb]

Thats the one, I've still got the drawings that you sent me at the time you were drawing it up. I have a couple  of old Baker catalogues and parts lists so will base the one for the monitor on that but your one with the fast and loose pullies would make a nice item to be belted to a hit and miss rather than the pair of wooden pitmans that the VJ drives.