Author Topic: 15cc Seal and 30cc Seal Major  (Read 9598 times)

Offline Jasonb

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Re: 15cc Seal and 30cc Seal Major
« Reply #60 on: June 20, 2019, 12:02:27 PM »
Just got to hope they put the camshaft holes inline with the crankshaft ones, may be worth checking while you have it set up and that the crank bore is horizontal when the top of the casting is horizontal in the X axis..

Can't see anything on the drawings or articles that I have that would suggest the bores are on ctr line?

Where did you get that precision ground test bar, do I need one too? ;)
« Last Edit: June 20, 2019, 12:35:01 PM by Jasonb »

Offline Jo

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Re: 15cc Seal and 30cc Seal Major
« Reply #61 on: June 20, 2019, 02:41:04 PM »
Can't see anything on the drawings or articles that I have that would suggest the bores are on ctr line?

See the Seal drawing of the cylinder (attached) from above the cylinder bores look to be on the same line as the crankshaft. I think the two bosses are actually supposed to be the water gland mounting.

You only need one of those special bars if you are intending on making a model ploughing engine  ::)

Jo
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Offline Jasonb

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Re: 15cc Seal and 30cc Seal Major
« Reply #62 on: June 20, 2019, 03:33:30 PM »
I took that as being the width of the oval boss, a measure of your glands may confirm that!

I can see its use for the ploughing engine now as it comes with a ploughed surface :LittleDevil: best get on with that BB1 before it all turns to iron oxide :stickpoke:

Offline Jo

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Re: 15cc Seal and 30cc Seal Major
« Reply #63 on: June 20, 2019, 04:38:17 PM »
... best get on with that BB1 before it all turns to iron oxide :stickpoke:

The BB1 is one of the sets of model castings I have already lined up for my retirement  ;D The problem is now that I am retired I still need more time  :facepalm: and castings  :mischief:


The required bore dimensions are just between the standard and into the extended capability of the chosen boring head. So I started by boring all four liner holes to the maximum 22.7mm that was obtainable using the long Swiss boring bar I had chosen for this job - it has to be a long boring bar as it has to do both the head and the bottom of the water jacket. It was a bit fun doing the lower hole as they were not absolutely inline with the top holes so there was a danger of thinking everything was dandy going through the top hole only to crash into the casting at the bottom.

The good news is that all four liner holes are out to 22.7mm and the boring head has had its extender fitted and the boring bar adjusted to just scrape the existing bore so we are ready to go for the morning  :cartwheel: That is if don't indulge in too many  :wine1: while we do a bit of casting fondling this evening  :embarassed:

Jo

P.S. How's the plumbing coming along on your traction engine  ::)
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Offline Jasonb

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Re: 15cc Seal and 30cc Seal Major
« Reply #64 on: June 20, 2019, 04:53:16 PM »
I think there is more chance of you getting all your casting sets made up and running than me plumbing up the Fowler :-[

Just can't get enthusiastic about it and even if I did plumb it up and do the other few bits it would just go back into the same corner as I'm not into sitting in a soggy field all day which reminds me why am I going to Guildford :headscratch:

Offline Jo

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Re: 15cc Seal and 30cc Seal Major
« Reply #65 on: June 20, 2019, 05:18:44 PM »
... which reminds me why am I going to Guildford :headscratch:

You are going so that you can inspire young people (and possibly older people ) that there is more to model engineering than playing Choo Choo trains  :stickpoke: and so that you can talk to fellow enthusiasts who build model engines and to admire/discuss the progress on their model engines  8)

We have to support the shows or we will loose them  :'(

Jo

P.S. There is also the free Bacon Buttie on Saturday morning  :P
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Offline Mike Bondarczuk

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Re: 15cc Seal and 30cc Seal Major
« Reply #66 on: June 20, 2019, 07:24:29 PM »
Hi Jo,

When is the Guildford meeting and is it still at the same location as for the last few years.

Mike
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Offline Jo

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Re: 15cc Seal and 30cc Seal Major
« Reply #67 on: June 20, 2019, 07:31:06 PM »
Hi Mike,

Same place as normal, first weekend in July (6th & 7th). I'll be there Saturday  ;)

Jo
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Offline Jo

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Re: 15cc Seal and 30cc Seal Major
« Reply #68 on: June 21, 2019, 11:13:58 AM »
So much for being able to start the final boring for the liners - Last night I luckily remembered that I had to hone the liners before fitting them  :old:

Not unexpectedly I found that I did not have a suitable size hone to be able to do this on Smelly  :( so back to the old way of doing it: find a piece of ali bar of a suitable diameter, cut a tapered bore to match my arbour and cut three slots to allow it to expand equally up the arbour. A bit of fine grinding paste some oil and gently move the  liner up and down the hone to smooth the surface.

Equally important is to get all the grinding paste off of the liners - time to try that little ultra sonic cleaner so filled with boiling water and washing up liquid I am trying the liners in that (having first used brake cleaner to get off the worst of the oil/paste.

Edit: I have just removed the liners from the ultrasonic cleaner and was very pleased by just how much extra muck it managed to extract from the liners  ;D

Hopefully after lunch I can do the cylinder boring for the liners  :)

Jo
« Last Edit: June 21, 2019, 11:24:42 AM by Jo »
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Offline Jasonb

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Re: 15cc Seal and 30cc Seal Major
« Reply #69 on: June 21, 2019, 11:22:04 AM »
Shame the lathe bed won't fit in the U.S. Cleaner :'(

I would not even treat the green dragon like that

Offline Jo

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Re: 15cc Seal and 30cc Seal Major
« Reply #70 on: June 21, 2019, 12:28:03 PM »
Shame the lathe bed won't fit in the U.S. Cleaner :'(

I would not even treat the green dragon like that

Having seen the quality of the metal that Chinese lathes are made of I totally understand your concerns JB   :facepalm2: But Mr Silky and my other ex-industrial lathes are made of a totally different quality metal than you are used to and they are designed to cope with much more than just a couple of drips of grindy oil  :Lol: A rag soaked in a bit of brake cleaner easily cleans it off, there is no worries about it soaking in ;)


First task is to bore each hole to fit the bottom of the liner, once the top will take the liner the bottom will as well:



Then we can look to take out the top that extra 0.2mm for the top step:



Last bit is to bore out the top for the collar:



Then the liner will push all the way in, but for now I will leave it nearly in its hole:



And after a cuppa I will start the next one  :)

Jo



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Offline Jo

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Re: 15cc Seal and 30cc Seal Major
« Reply #71 on: June 21, 2019, 04:10:58 PM »
Another two cuppa's (and some sticky wotsits  :-X ) later and we have four liners fitted:



I decided to play it safe and try marking the valve guides 20.63mm out from the liners and it is clear they have to go over 24.63mm. We are all set up to repeat the same set of machining tasks job for the valve guides  :wine1:

Jo
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Offline Laurentic

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Re: 15cc Seal and 30cc Seal Major
« Reply #72 on: June 21, 2019, 10:52:23 PM »
Jo, on the basis that no question is stupid if you don't know the answer, (and you may find this stupid but I don't know the answer!), with your ali, or aloominum, hone, I can understand the taper bore and the three slots but are the three slots joined at any point and if so where?  Logic says they are, but the photo seems to show the same slots emerging from both ends of the liner, which would mean three seperate slices of ali up the liner???

Chris

Offline Jo

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Re: 15cc Seal and 30cc Seal Major
« Reply #73 on: June 22, 2019, 07:35:14 AM »
Morning Chris,

In case others have similar questions I will go through the whole honing tool design:

The honing set up consists of two metal arbors that I have cut tapers on, to match a tapered reamer, on the end is a thread which is used to force a mandrel up the taper.

The mandrels are bits of Ali which have been drilled and reamed using said tapered reamer. To enable these mandrels to expand I have cut slots down the side of the Ali, in this case 3 slots: 2 only go part way down the Ali from opposite directions and the third goes all the way through the Ali (on other mandrels I have chosen to cut to depth on all but one slot, the last being taken through I am not sure which is best  :noidea: ). The sharp edges are then cleaned up....

In use the Mandrel is slid onto the Arbor and the nut on the thread is used to adjust the size of the mandrel by forcing it up the taper so that it is fractionally under the size of the bore of the liner. Oil and grinding paste is applied to the outside of the Ali and the liner gently moved up and down with the lathe running slowly. Once the liner moves freely over the mandrel the bore of the liner is checked and if necessary the nut tightened to expand the mandrel further for another hone.

Hopefully that is clear  :) A pic attached of said mandrels and the tapered reamer used.

Jo
« Last Edit: June 22, 2019, 08:20:58 AM by Jo »
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Offline ChuckKey

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Re: 15cc Seal and 30cc Seal Major
« Reply #74 on: June 22, 2019, 09:14:01 AM »
Pedantry Corner: what you have there are laps. Hones are the things with solid blocks of bonded abrasive material.