1/4 scale Otto Langen 1866 Engine

[Jo]

When you selling the o&l castings.
Robbie

After the patterns and drawings are proven 


Jo

[Jo]

Castings have arrived  I am not allowed to play  . But I had to have a quick check 

The cylinder easily fits in a three jaw, with plenty of spare bed to allow for boring between centres... I had no worries about the flywheel fitting on the standard faceplate but it looks like it will also fit on the wimpy little one 

And the cylinder looks like it is the right size for the four jaw chuck. which means it can be bored and then mounted on a mandrel in the dividing head for shaping up 

Jo

[Jasonb]

Knowing what the castings have cost us it would be interesting to do a cost comparrison with using solid CI bar as I don't think we have gained much by using this foundry except a smaller pile of swarf. Plus there would be no risk of flaws or hard spots.

[Jo]

The Flywheel would need 300mm dia CI bar and I recall the cutting cost was £25 a time... M-Machine do not quote more than 180 mm dia and that is £21 for 25mm. I think MJ quoted about £40 per 25mm  The column would need to come out of 110mm dia which is £11 per 25mm = £155. The base would need 160mm diameter which is £18 per 25mm = £108.   Plus postage and Vat 

So yes not a lot cheaper than buying barstock and potentially a lot less hassle. As a casting set they are not commercially viable  . 

Jo

[Jasonb]

You could save on the column if made as per my Alibre drawings which had the lower moulding as a separate ring.

J

PS Jo is it better to move some of these OL comments and photos to the OL thread?

[Jo]

Looks like everyone but me has started playing with their OL castings 

Jo

[Jasonb]

Does Eric need a drawing or is he just seeing whats under the skin?

Has he got his ctr straight into the cored hole? The core was well off on mine

[Jo]

He pinched mine when he dropped off the castings 

So not to be out done...

The Cylinder has been supported on the not in the centre hole at the top and in the three jaw. Ignoring the top of the cylinder going all over the place it is then possible to machine a short length to provide something to rest a steady on. It was interesting the difference in surface finish between a Japanese tip and a UK brought one.

Then the cylinder can be turned round and having set up the steady using a very thin feeler gauge the end face can be machined square.

Now I need to look at centring up that bore.  My long boring bar which will reach over the centre of the column needs a 35mm hole and by the time that is bored round it will be big enough for that bar. But in the mean time I need to find a thinner boring bar to start things off. I could use a drill 

Jo

[Jasonb]

Don't let him make it to that, it does not have a moulding on it that was originally drawn as a separate part when we had not decided to use a casting over bar stock.

I took a different approach, cleaned up its botton with a file, turned a tight fitting plug from an odd bar end and then tacked it in with 3 small drops of 5min epoxy so that if it took it out teh lathe teh plug would not move. Scribed in from the edge of the casting in 4 places and then drilled a ctr hole in the best position for centre.



Then held the top end in the 4 jaw and got it to run true and tailstock at the other end. Held like this the whole of the outside could be turned including facing off the bottom which was my datum for setting out all the heights. The long area that will be fluted was left parallel at this stage, taper will be added later



[youtube1]https://www.youtube.com/watch?v=Nfi6EnyQ0jM&feature=youtu.be[/youtube1]

While held like this the fixed steady was used to bore half way along to 3mm under finished bore.



After this the chucking piece was cut off the top and held the opposite way round the top was faced off to length then the rest bored out to 3mm undersize.

J

[Jo]

Don't let him make it to that, it does not have a moulding on it that was originally drawn as a separate part when we had not decided to use a casting over bar stock.

So you are saying that you have not sent me the up to date drawings of the bottom then 

Jo

[Jasonb]

Yes that is what I said in the e-mail a couple of days ago. You said you were trying not to look at them until work changed so I said let me know when it changes and I will send revised drawings

"Let me know when you are on wasting time and I'll send you the revised Otto drawings, I have added the decorative panels and slightly adjusted their size to suit available cutters. Also found I made the column pattern a bit longer than needed but it does give something to hold it by so all the outside can be turned at one setting if the bottom end is
plugged for tailstock support."

When I drew the column over 2 years ago it was so it could be made from 3" CI bar, subsequently you two decided you wanted castings, I drew my pattern to suit, did not get round to altering column drawing until I needed it.

[Jo]

But you forget Surus  keeps giving me hassle: I am struggling most of the time to know which way up a wine glass should go 

Jo

[Jasonb]

Maybe it would be best you don't do anymore work on expensive castings until you are in the right frame of mind, it's not easy to stick bits of swarf back onto the solid!

[Jo]

That could be months  I am sticking to simple things, this is just to skim the casting to check there are no scabby bits.

Someone has found a cradle for boring his cylinder  I am sure he was going to get rid of that rust...

Jo

[Jo]

I have finished the end bore with an internal chamfer to give the rotating centre more to grip on. At this stage we can take away the fixed steady and support the casting on the centre. It is a bit tight as that is a 38mm diameter centre in a 36.5mm diameter hole

While still supported on the centre a short area was machined on the other end to take the steady once the casting is turned round. To make life easier this was done by reversing the feed screw so that the carriage was going away from the chuck 

Just to remind ourselves the fixed steady is fitted using a very thin feeler gauge to check the gap to the fingers. Then we are off repeating what has been done on the other end  .

Jo