1/4 scale Otto Langen 1866 Engine

[Bluechip]

Jo

As you have no doubt observed, I'm not the sharpest knife in the drawer but I can't see why the gap should be there ??

I have seldom used my fixed steady but always used it rubbing.

Surely the 'leverage' of the cut on a work-piece that long is going to make it chatter.

Dave   

[Jo]

Hi Dave 

If you start with the fingers rubbing you have no guarantee that the work is actually central as the fingers can push it over. This means the work can "walk out the chuck" as it goes round

By using the wafer thin feeler gauge you can set an equal gap on all the fingers getting the work central, then you can decide if you want to touch the fingers in a fraction more but normally the gap is just enough for some lubricant.

Jo

[Jasonb]

Before we get too carried away with the castings I'll take a step back and post about the pattern making.

Base First.

It was decided to make basic patterns that the more detailed features could be machined from rather than detailed castings with all the detail "as cast" so the first job was to draw up a pattern that would allow for shrinkage, draft so the pattern could be pulled from the sand and also give a machining allowance. I did this in Alibre and by making the pattern semi transparent it was easy to overlay it onto the finished part to make sure there was enough metal all round.



Armed with a print of the drawing it was time to cut some wood, I had some 40mm thick beech worktop left over so cut up some blocks from that on the bandsaw.



A good coat of glue was applied to the mating surfaces



Before they were clamped up and left to dry, not easy to see but I also added a sheet of paper into the middle of the sandwich which will make it easier to split the pattern in two when it has been shaped.



Two holes were drilled at right angles to the joint, these will take alignment pins later. I also rough marked an octagon on the top with corners set across the parting line.



The bandsaw was used to cut off most of the waste marked by these lines.



To make things easier to hold on the rotary table a disc of plywood was screwed to the bottom of the pattern and this disc could then easily be bolted to the table and tailstock support added. I then used a 3/4" router bit to start shaping the pattern.







A bull nose cutter was then used to add fillets to the internal corners



With the milling done the machine was cleaned up before returning to the woodwork shop



The flared bottom was done by machining a strip of wood with a tapered top and then cutting this into pieces on teh chop saw before gluing to the main pattern





This was set aside while I tackled the column.

J

[Jo]

  My Cylinder casting is a reject.

Jo

[Jasonb]

How deep have you gone? I had balls of iron like that but they went as I cut into the metal, there is quite a bit of metal to come off.

[Jo]

That is within 2mm of the finished size.

Jo

[AOG]

Can't you fill it with JB weld?

Tony

[Jo]

Having paid an arm and a leg for the casting I would prefer it was a good one.

There is also that little problem that this is an IC engine: When it first fires up it is likely to blow the side out of the cylinder.

Jo

[Jasonb]

That is probably why the price was so high, he has covered himself as he expected them to come back.

Whith a bit of jiggling of where the lowest mounding is placed you could still have 12mm to come off so keep cutting like I did.

J

[Jo]

The foundry has promised to cast another cylinder next week  .

Jo

[Jo]

The base looks ok 

Jo

[Steamer5]

Hi Jo,
  Got enuff  ....I hope!

Cheers Kerrin

[Jasonb]

Column Pattern

I modeled a pattern in Alibre in much the same way as I did for the base and then printed off a 2D drawing to work from starting by cutting some basic bits of beech.



The excess material was trimmed off on the bandsaw



I did not glue the wider section as I did not want to risk it not coming apart when the pattern was split into two so left this section uncoated



After which it was clamped up and left to dry. You can see the sheet of paper left in the joint better in this photo than the one for the base.



After knocking off the corners on the bandsaw it was mounted up on the lathe. You may just be able to spot a washer slipped onto the tailstock ctr, this is quite important when working with glued up parts you intend to split as if you don't use a washer the pressure of the ctr while turning can wedge the two halves apart at the wrong moment.



The engineering lathe makes quick work of wood with a fast speed and feed coupled with a sharp CCGY type insert.



After a bit of sanding and filling the two patterns are starting to look more like an engine.



After the first couple of coats of paint and sanding between coats it was time to split the patterns in two. A quick blow to a 1" chisel on the joint line soon had the paper split and then that was sanded off.





With the bandsaw table tilted a couple of degrees draft angle was added to the ends.



J

[Jo]

This is where it now gets boring I can tell some of you don't appreciate my humour 

While I am busy wasting time I am going through the drawings and checking for errors  In doing this I am finding many variations on the theme. The Patent engine dates from 1866. Then there is the advertising blurb that came out in 1866. Then there is the production engine blurb which still does not match the 10 production engines  Then there is the engine Wayne Grenning chose to model 

Jo

[Dave Otto]

Confusing isn't it

Have you seen Wayne's recently completed 1:1 Otto & Langen? It is a masterpiece!
When you say drawings are you talking about the Lenez drawings, your own, or maybe that other set that is pretty much a copy of the Lenez drawings?

I will be curious to see what you end up with on the ratchet and pawl;the ones in Emmett's drawings do work kind of, but they could be improved on.


Dave