Author Topic: Vince's version of the MEM Corliss  (Read 208509 times)

Offline vcutajar

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Vince's version of the MEM Corliss
« on: February 19, 2013, 06:36:52 PM »
Well here I am at the start of a new build.  I had planned to do a Hoglet after the Kiwi but was having difficulties (until Jason pointed me in the right direction) getting the original back-issues for the Hoglet.

In the meantime the MEM Corliss made its appearance and I sort of fancied doing it.  The Hoglet plans have arrived but I am still going to do the Corliss as it's a new challenge.  I have never built steam models and most of the terminology of the parts are still new to me.

Late last week I managed to get hold of a slice of mild steel for the flywheel. 



I was not going to start something and then find out I can't get hold of the material for the flywheel.  It's 200mm diameter and 50mm long.  It cost me 74 Euro and that includes the cutting of the slice (45 Euro).  The cutting was more expensive than the material!!  I guess beggars are not choosers.

I started work on the flywheel a couple of days ago but did not want to post anything until I made sure I could mount it to the lathe and and I could reach all machining areas.

I am going to go Metric but will be using direct conversions (1"=25.4mm).  The clearance holes and tapped holes will be Metric.  So first thing I did was print the flywheel pdf and convert all dimensions to Metric.



Blued up the best face of the material and using a divider marked the flywheel with spokes so that I could see where I could drill the mounting holes.



I decided that it would be a good idea to face off the other side before.  So I clamped it to the mill table and put a 20mm endmill in the collet to start milling that face.  That's when the first problem cropped up.  I do not have enough Y axis travel to reach all parts. This flywheel is going to stretch the capabilities of my poor chinese 3-in-1 lathe and X3 mill.  I remembered I had a flycutter which I very rarely use because I never get a nice finish.  I tried it and I could reach the top and bottom of the face.  I was not worried about the finish because I would still be machining this same face on the lathe.

Flycutting finished



and the four mounting holes marked



and drilled with a deep counterbore for the allen head bolts.



This morning I bolted the flywheel material to the faceplate and managed (that was heavy) to fit it to the lathe. Experimented with various toolpost configurations to get it as close a possible to the face.  Set the lathe to its slowest speed (160 RPM) but was having some doubts if this is slow enough for this diameter.  Looked it up and I got an RPM of about 50 if using HSS tools.  Good thing I am going to use carbide tools for hogging it down to size.

Made a first cut on the OD to see if I had enough reach



and the face with a different tool configuration.



At least now I am satisfied that I could reach (just) all areas.  Now to start hogging the thing and hopefully the lathe spindle bearings won't give up the ghost (keeping my fingers crossed).  Thankfully the material is nice to machine.

Vince
« Last Edit: April 14, 2013, 06:07:30 PM by vcutajar »

Offline rudydubya

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Re: Vince's version of the MEM Corliss
« Reply #1 on: February 19, 2013, 06:54:19 PM »
Looks interesting and challenging Vince.  Thanks for sharing your build.  I'll be following along.

Regards,
Rudy

Online b.lindsey

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Re: Vince's version of the MEM Corliss
« Reply #2 on: February 19, 2013, 07:02:21 PM »
Looks good so far vince. That is a sizeable piece of steel there but glad to see you got it all mounted with a little wiggle room to spare. Will look forward to your progress on this one.

Bill

Offline tel

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Re: Vince's version of the MEM Corliss
« Reply #3 on: February 19, 2013, 07:21:23 PM »
Yes, I'm watching with interest as well - that flywheel alone is a big project.
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Offline Ramon

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Re: Vince's version of the MEM Corliss
« Reply #4 on: February 19, 2013, 09:34:48 PM »
Hi Vince - nice to see you have got off to a good a start. That's a big lump to 'pick' away at but 'slowly slowly and you'll catchee monkey'  ;)


Something that I find effective which you may like to try if using HSS.  Keep the cuts very light .25 - .35mm - put the speed up a bit from normal and use very fast feed rates. It's quite surprising how quickly the metal is removed despite the shallow cuts - a lot of passes yes but this puts far less strain on the 'kit'. Because of the 'thin' cut the heat does not generate so quickly bearing in mind I do virtually all machining dry except for the odd wipe of a coolant brush. Despite this the tools stand up okay even on En24T .

Hope that's of use and not 'teaching granny'

I look forward to seeing and reading more of your build as it develops.

Regards - Ramon
"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 vcutajar

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Re: Vince's version of the MEM Corliss
« Reply #5 on: February 19, 2013, 09:59:22 PM »
Thanks guys for checking in and the support.

Quote
that flywheel alone is a big project

How right you are.  Everytime I look at it I find that there is a new problem to solve.  This evening while hogging the OD of the flywheel I realised that I do not have anything to accurately measure the OD.  All my calipers are 6"!!  First thing I did as soon as I got on the computer was to order a 12" digital caliper.

Quote
Hope that's of use and not 'teaching granny'

Thanks for the suggestion Ramon.  I will try it out when getting closer to the finished dimension.

Vince

Offline Ramon

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Re: Vince's version of the MEM Corliss
« Reply #6 on: February 19, 2013, 10:12:15 PM »
Hi Vince - Sorry I've misled you - that's for the roughing and waste removal. It does work well but regrind the tool and reduce everything to normal for those finishing cuts

Ramon
"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 Bearcar1

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Re: Vince's version of the MEM Corliss
« Reply #7 on: February 19, 2013, 10:16:27 PM »
HI vince. Wow! That is one big mahmoo of a lump. You seem to be working through the problems well and I hope that as you continue along in the project that the problems become less of a nuisance and you get some clear water for smooth sailing. You just have to 'hold yer mouth right" is all. (now Tel will say that is an old adage from down under)  :embarassed: :ROFL: :shrug:




BC1
Jim

Offline Dave Otto

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Re: Vince's version of the MEM Corliss
« Reply #8 on: February 20, 2013, 01:25:16 AM »
Alright Vince; a new project :cartwheel:

I have pulled up a chair and grabbed a glass of :DrinkPint: and will be along for the ride.

Dave

Offline tel

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Re: Vince's version of the MEM Corliss
« Reply #9 on: February 20, 2013, 02:48:54 AM »
Quote
How right you are.  Everytime I look at it I find that there is a new problem to solve.  This evening while hogging the OD of the flywheel I realised that I do not have anything to accurately measure the OD.  All my calipers are 6"!!  First thing I did as soon as I got on the computer was to order a 12" digital caliper.

You just need to cut a gauge out of a bit of sheet metal - something like a big horseshoe. Actually, there is no reason why rule measurement won't do for that job - the OD doesn't fit anything.

And yes - hold yer marf right, as we say down here!
The older I get, the better I was.
Lacerta es reptiles quisnam mos non exsisto accuso nusquam

Offline Don1966

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Re: Vince's version of the MEM Corliss
« Reply #10 on: February 20, 2013, 03:07:42 AM »
Vince I will be tagging along also, I look forward to your progress. I had posted a spread sheet on spoke offset radius calculation. If you missed it its here http://www.modelenginemaker.com/index.php/topic,1271.0.html you can use it for straight spoke calculation. It can be changed to metric if you want to, the sheet is not locked.

Don

Offline Captain Jerry

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Re: Vince's version of the MEM Corliss
« Reply #11 on: February 20, 2013, 03:40:57 AM »
Go Vince!  This should be fun.  At least three different ways to build from the same plans. 

Jerry
There are thing that you can do and some things you can't do.
Don't worry about it. try it anyway.

Offline vcutajar

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Re: Vince's version of the MEM Corliss
« Reply #12 on: February 20, 2013, 07:35:08 AM »
Thanks guys for the support and suggestions.

Quote
Sorry I've misled you

Got it now Ramon.  Does it happen to anybody else?  You read something and your mind gives you the wrong interpretation of what you are reading.

Quote
Actually, there is no reason why rule measurement won't do for that job

Yes, I guess you are right Tel.  No need of accuracy on the OD but it gave me an excuse to buy a new tool.

Quote
I had posted a spread sheet on spoke offset radius calculation.

No Don I did not miss it.  As soon as I saw your post I thought it was perfect timing for me.  It has been already downloaded.  All I need to do is try to figure out how to use it.

Vince

Offline vcutajar

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Re: Vince's version of the MEM Corliss
« Reply #13 on: February 21, 2013, 10:47:51 AM »
Don

I think I finally figured out how to use your excel sheet.  It is going to save me lots of work.  It will also accept metric dimensions.  I did not need to change anything in the sheet.

In the meantime I am still hacking away at the lump of metal and also experimenting with different tools how to create the recess in the face.  I would like to avoid using a trepanning tool as I suspect I might not have enough HP and rigidity on my smallish lathe.

Vince
« Last Edit: February 21, 2013, 02:32:20 PM by vcutajar »

Offline arnoldb

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Re: Vince's version of the MEM Corliss
« Reply #14 on: February 21, 2013, 04:48:12 PM »
I'm watching with interest as well Vince - good start  :ThumbsUp:

A narrow trepanning tool should work - just take light cuts.  Another option is to use a V shaped tool with adequate clearance and turn out most of the recess. This will leave angled sections next to the rim and the hub that can then be cleaned up with a boring tool at the rim and a right-hand cutting tool clamped down like a boring bar for the section next to the hub.
Lots of cranking on the crosslide either way  ;)   

How are you planning on holding the workpiece to the faceplate to recess the other side ?

Kind regards, Arnold
Building an engine takes Patience, Planning, Preparation and Machining.
Procrastination is nearly the same, but it precludes machining.
Thus, an engine will only be built once the procrastination stops and the machining begins!