Author Topic: Two Cylinder Engine  (Read 19641 times)

Offline Roger B

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Re: Two Cylinder Engine
« Reply #30 on: March 04, 2018, 12:19:00 PM »
The second end of the timing cover was rounded off then it was set up on the mill using the two 6mm holes for alignment. I then started hollowing it out with the boring head. My cheap brazed carbide cutters were the wrong profile for a blind hole and I have no means of reshaping them other than a diamond hone so I tried my 8mm boring bar with an APT aluminium tip. This worked but was a bit chattery. Cutting it to half the length would certainly have helped, I may see if I can find some cheap holders and cut them to various lengths.

Clean up and back to lathe mode for the next steps.
Best regards

Roger

Offline Roger B

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Re: Two Cylinder Engine
« Reply #31 on: March 04, 2018, 06:52:46 PM »
I mounted the big end in the 4 jaw independent chuck and turned the conrod shank initially to 8.5mm. Then using a profiling tool I shaped the ends and took it down to 8mm. Same procedure for the 2nd rod.
Best regards

Roger

Offline Ramon

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Re: Two Cylinder Engine
« Reply #32 on: March 05, 2018, 08:56:08 AM »
Hi Roger - Rather late on board, I must admit to having only just looked at your project for the first time.  :-[

That's some nice machining you've done there and a super photo coverage of the processes too. I've yet to do a (one piece) two throw crank - you've shown just how much work goes into such a component   :praise2:

Nice work all round  :ThumbsUp: keep it coming

Regards - Tug





"I ain't here for the long time but I am here for a good time"
(a very apt phrase - thanks to a well meaning MEM friend)

Offline Roger B

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Re: Two Cylinder Engine
« Reply #33 on: March 10, 2018, 11:03:10 AM »
Thank you Tug  :ThumbsUp:

I then cut the big end caps off using a 0.5mm wide slitting saw. The rods were held in my new Proxxon steel vice and cut off in the lathe. Next the holes for the big end bolts were opened out to 2mm and I started to tap the big end caps. Problem  :toilet_claw: The M2 tap broke! I was initially not sure why as I was using the tapping fixture and lubricant  :headscratch: When I looked at the pictures afterwards I realised that I had started with the second tap rather than the taper  :facepalm:
Hopefully I can get the broken bit out with Sal ammoniac.
Best regards

Roger

Offline Roger B

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Re: Two Cylinder Engine
« Reply #34 on: March 10, 2018, 03:34:47 PM »
Did I mean Alum for removing broken taps  :headscratch: I'll to look it up and see what it is called here.

As the tapping had to stop I moved on to the spotfacing cutter for the big end bolts. This is a short piece of 4mm silver steel with some cutting edges formed with a junior hacksaw and a half round swiss file. It was hardened and fixed to a 2mm shaft with Loctite. The cutting was done by hand with the shaft held in a small drill chuck.

Next I started on the cylinder liners. The first is made from a ~25.5 mm dia core I cut out of the cylinder block for the horizontal engine. The second will be made from a piece of nominal 25mm cast iron bar.
Best regards

Roger

Offline fumopuc

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Kind Regards
Achim

Offline crueby

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Re: Two Cylinder Engine
« Reply #36 on: March 10, 2018, 11:20:47 PM »

I have bought it here.
https://www.ebay.de/itm/9-78-kg-Alaun-Kalialaun-Kaliumaluminiumsulfat-Kristalle-Knete-Hortensien-900g/263538342180?hash=item3d5c1bf924:g:fj0AAOSwUUdaoPue
Yup, can just see it now, buy some from there for shipment over here, and just watch the look on the customs  guys face as he sees the big bag of white powder in the package....!  ;D

Offline Art K

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Re: Two Cylinder Engine
« Reply #37 on: March 11, 2018, 12:40:30 AM »
Roger,
I saw Achim's post and didn't go to google translate. It must be one of these things that eat out taps. I'm just glad it was the end cap & not the rod, much easier to make a replacement & chalk it up to experience.
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline MJM460

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Re: Two Cylinder Engine
« Reply #38 on: March 11, 2018, 08:05:25 AM »
Hi Art, why not try buying some aluminium sulphate, with or without the extra "I", and try it for future reference.  It should not be very expensive.

It is normally a water clarifier but now I think of it, I have seen previous references to using it for this purpose.  Presumably the aluminium and iron exchange somehow to give a ferrous (or ferric) sulphate.  You would need a strong solution and probably some time.  Obviously no good on a steel component.

Continuing to enjoy your great build log, thank you.

MJM460
The more I learn, the more I find that I still have to learn!

Offline Roger B

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Re: Two Cylinder Engine
« Reply #39 on: March 25, 2018, 08:13:45 AM »
I managed to get a small quantity of Alum and the bearing cap is currently sitting in a strong solution. There are some signs of corrosion but I expect it will take a couple of weeks.

I bored out the liner until the lap would just go in and then chamfered the end to ease get the piston rings in. It was then parted of over length so it can be faced off when fixed into the block. It was interesting that after boring the outside was no longer quite round, but not a problem as I had left 0.2mm to skim off.
The second liner was made from a different piece of CI which showed a much better surface finish using the same tools.
Next I need to mount the cylinder block in the lathe and bore the recesses for the top of the liners and the water jacket spaces.
Best regards

Roger

Offline fumopuc

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Re: Two Cylinder Engine
« Reply #40 on: March 25, 2018, 09:38:07 AM »
I managed to get a small quantity of Alum and the bearing cap is currently sitting in a strong solution. There are some signs of corrosion but I expect it will take a couple of weeks.
....
Hi Roger, when I have done it last time in Aluminium, I have kept the solution under 70 to 80C for nearly 30 hours. Every 4 hours some fresh Alum was added.
Kind Regards
Achim

Offline Ian S C

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Re: Two Cylinder Engine
« Reply #41 on: March 25, 2018, 12:54:22 PM »
Keep it warm(the alum solution), and every now and then poke a bit of wire down the flutes of the tap to get the gas bubbles out, it doesn't really take too long until you can wiggle the tap, after which it won't be long until it will come out.
Ian S C

Offline Roger B

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Re: Two Cylinder Engine
« Reply #42 on: March 25, 2018, 05:53:41 PM »
Currently the part is in a little jar with fresh alum at the bottom which I shake every time I go past it, no real hurry I have plenty of other parts to make  ::)

As I was in lathe mode I tapped the out of position holes in the crankcase out to M5 and Loctited a couple of plugs in. I also tapped the other bearing cap in case it also needed and Alum bath  :facepalm: No problems  :)

I then fixed the centering plug onto a piece of 6mm silver steel held in an MK collet in the mandrel  and set up the cylinder block to start boring out the water space.
Best regards

Roger

Offline Art K

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Re: Two Cylinder Engine
« Reply #43 on: March 25, 2018, 09:56:01 PM »
Roger,
The twin is coming along nicely.
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline Roger B

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Re: Two Cylinder Engine
« Reply #44 on: April 01, 2018, 01:25:02 PM »
Thank you Art  :ThumbsUp:

I turned the cylinder block round so I could finish boring out the water space and cut the recesses for the top of the liners. The passage between the two water spaces was then opened out with a cutter in the Proxxon hand tool.

I then went back to the crankcase and cut off the plugs, filed them flat and re-centred and drilled. The drift was quite surprising  :headscratch:

Finally have received my new deep parting tool (2mm wide 19mm deep blade) I finished off the crankpins with a significantly better finish than before  :)
Best regards

Roger