Author Topic: 1909 Mercedes Aero Engine  (Read 23751 times)

Online Vixen

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Re: 1909 Mercedes Aero Engine
« Reply #45 on: December 07, 2018, 07:59:56 PM »
The weather looks to be  good.... are you not going down to stroke one of your lorries?   :noidea:

Hello Stranger

Nothing wrong with that, considering the number of years you have put into each of them.

That was an excellent fix on the base flange of the errant cylinder block.

Do you have any Trefolex cutting paste? It is perfect for stopping drills. taps and reamers and even milling cutters from picking up in softish aluminium castings.

Mike
It is the journey that matters, not the destination

Offline Old Bill

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Re: 1909 Mercedes Aero Engine
« Reply #46 on: December 07, 2018, 09:29:54 PM »
Hi Mike and Jo.

The lorry I mentioned in my intro in 2012 has taken 29 years to get to this stage and we plan to finish it over Christmas. A few more days are neither here nor there! In the meantime, I am thoroughly enjoying machining something that is smaller than the mill and cutting 7BA instead of 1/2" BSW. It is great to do some model engineering indoors in a heated workshop. (Perhaps I am getting old...) Living 200 miles from the lorry doesn't help much either. I'll post some recent pictures on my intro in a moment and some more engine this weekend if I have no disasters!

I tend to use WD40 as the cutting agent on aluminium and that seems to work quite well for general machining. I think I let the flutes choke on the reamer and should have stopped the machine to clear them half way through the cut. It is all part of the learning process.

Steve   :)

Online Vixen

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Re: 1909 Mercedes Aero Engine
« Reply #47 on: December 07, 2018, 10:41:16 PM »
Hello Steve

Agreed, WD40 is fine for general machining, but for those high load conditions such as threading, reaming or key way cutting a little Trefolex cutting paste significantly reduces friction and the risk of aluminium cold welding (picking up) to the steel tool. Try it, it's got to be better than white spirit with a dash of mineral oil. AKA   WD40

Mike
It is the journey that matters, not the destination

Online Vixen

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Re: 1909 Mercedes Aero Engine
« Reply #48 on: December 07, 2018, 11:49:21 PM »

A few more holes this weekend with a bit of luck.

Steve  :)

Wasn't it 'Old Bill' who said, " If you knows a better 'ole..... go for it"

Mike
It is the journey that matters, not the destination

Offline Jasonb

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Re: 1909 Mercedes Aero Engine
« Reply #49 on: December 08, 2018, 07:17:28 AM »
You are also using a hand reamer in the mill so run it slowly as the longer cutting edge puts more load on it.

On long small holes you need to clear the flutes quite often, though this will depend on the size of your pilot as to how much is to come off.

Good to see the cylinders all lined up now.

Offline Old Bill

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Re: 1909 Mercedes Aero Engine
« Reply #50 on: December 08, 2018, 08:09:46 AM »

Wasn't it 'Old Bill' who said, " If you knows a better 'ole..... go for it"

Mike

Quite right!

Steve   :) 

Offline Old Bill

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Re: 1909 Mercedes Aero Engine
« Reply #51 on: December 08, 2018, 08:12:24 AM »
You are also using a hand reamer in the mill so run it slowly...

Thanks Jason. It is a while since I did this sort of thing and I forget. You are quite right about it cold welding. Notjhing I can't get over but annoying all the same. Hopefully, I will be back up to speed by the time I finish!

Steve   :)

Online sco

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Re: 1909 Mercedes Aero Engine
« Reply #52 on: December 08, 2018, 10:09:30 AM »
Following your build closely Steve.  I've put one of these casting kits on my Christmas list so fingers crossed  ;D

Keep up the good work,

Simon.
Ars longa, vita brevis.

Offline john mills

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Re: 1909 Mercedes Aero Engine
« Reply #53 on: December 08, 2018, 10:43:57 AM »
I would rather use one of the soluble cutting fluids normal coolant if you can flow plenty down the hole it can flush
the chips out as well.if you can contain it to the machine.i have found a work shop when working one of the contractors using wd40 machining alloy the workshop was un usable for the rest of the day with the fumes
they would burn your eyes.why not use a proper cutting fluid.it does work.

Offline Old Bill

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Re: 1909 Mercedes Aero Engine
« Reply #54 on: December 09, 2018, 08:33:02 PM »
I don't machine aluminium very often so I am not really set up for it. I do have soluble suds oil that I use with steel. Would that be appropriate with aluminium?

In the mean time, I have made a very little progress with the cylinder blocks. First job was to finish drilling the holes in the top so the coolant holes and the holes for the rocker shaft pillars were completed.



Then it was on to the exhaust ports. These were milled off using the drilling set-up and then marked across with the height gauge to keep them in line. Finally, the block was held square against and angle plate and simply supported with a piece of wood whilst I put the holes in.



All uneventful.



Now it is time for the more difficult angled holes. I have been puzzling how to achieve these for a while. Eventually, I decided on a mounting plate with a spigot that I could hold in the dividing head. I made the plate slightly longer than the base of the block so that I could get a good hold of it in the vice.



I faced off the water inlets and drilled them through.



The mixture inlet holes are at a compound angle, defined in the drawings as 18 up and 34 rotated. I set up my dividing head and elevated it by 18 and rotated it.



Unfortunately, the alignment doesn't look quite right to me so I need to think some more on this one. It is essential that the port comes out above the valve seat of course!



I am also pondering on whether to drill the valve guides before inserting them or by drilling through the ports. There are a few challenges in this engine!

Steve   :) 

Offline john mills

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Re: 1909 Mercedes Aero Engine
« Reply #55 on: December 09, 2018, 09:33:56 PM »
with coolant i have never changed the coolant on a machine to cut alloy or different materials.

Offline Art K

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Re: 1909 Mercedes Aero Engine
« Reply #56 on: December 09, 2018, 11:12:36 PM »
Steve,
Still following along. Never built an engine from castings yet. But I can see where it would be frustrating to see the assigned angle dimensions don't line up. How are the rest of them, do they all mismatch in the same place?
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline Old Bill

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Re: 1909 Mercedes Aero Engine
« Reply #57 on: December 16, 2018, 08:42:54 PM »
Hi Art.

The dimensions on the drawings are accurate but are a bit scant in places. There is a note next to these inlet holes which says to check the casting and I feel that the position of these is very susceptible to casting variation. In the end, I have laid it all out on the drawing board at five times full-size after measuring the actual castings and have calculated the angles to suit.

I managed to find a couple of hours this afternoon and tried setting it up to the new numbers. It looks a lot better.



Then it was just a case of using a centre drill and taking my courage in both hands.



Fortunately, it worked satisfactorily although I do seem to be a whisker off-centre. Nothing I cant live with.



I finally faced the flange (at yet another angle) and drill the holes for the studs.



I'll do the other tomorrow and then only the spark plug holes will remain.

Making progress if a lot slower than I would like. This earning a living business seriously gets in the way!

Steve :)

Online Vixen

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Re: 1909 Mercedes Aero Engine
« Reply #58 on: December 16, 2018, 08:58:47 PM »
Hello Steve,

Using a centre cutting end mill or slot drill is sometimes a more accurate way of starting a hole at an acute angle to the surface. Even a stubby centre drill will try to deflect to one side due to the angled point,  An end mill does not have this problem.

You will also get deflection if you try to enlarge the angled pilot hole with a larger drill, again an end mill or slot drill will avoid this deflection.

Mike
« Last Edit: December 16, 2018, 09:08:31 PM by Vixen »
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Offline Art K

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Re: 1909 Mercedes Aero Engine
« Reply #59 on: December 17, 2018, 03:12:14 AM »
Steve,
I'm with Mike even if you only use the endmill to give you a flat spot to keep the hole from walking. Sounds like you have to make due with a lack of good prints that actually match what you have for print dimensions. I'm not sure what I'd have done in your shoes. Looks good.
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King