Author Topic: CHUK2 - Alyn Foundry Flame Gulper  (Read 10364 times)

Online Twizseven

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Re: CHUK2 - Alyn Foundry Flame Gulper
« Reply #75 on: February 03, 2020, 12:24:55 PM »
Completed conrod

Quick video showing it turns over.  Still needs big end pin and inlet valve and associated link.

Colin

[youtube1]https://youtu.be/yi6IHo-PPxs[/youtube1]

Offline Alyn Foundry

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Re: CHUK2 - Alyn Foundry Flame Gulper
« Reply #76 on: February 03, 2020, 02:00:55 PM »
That's running really freely Colin, excellent work!

You will have noticed from that demonstration that the piston wants to return to TDC thus aiding in the
" vacuum " part of the power stroke.

This is what made CHUK 2 the most effective of the three different engines.

Cheers Graham.

Online Twizseven

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Re: CHUK2 - Alyn Foundry Flame Gulper
« Reply #77 on: February 03, 2020, 11:27:45 PM »
Was going quite well today.

Just prior to parting off the big end bolt I tried the crank web on it.  I  did it up just a little too hard and BANG :censored: :censored: :censored:  I split the casting at its weakest/thinnest point.

As it did not break completely I can at least still re-assemble everything and carry on making inlet valve bits until replacement casting (hopefully) appears.

Colin

Offline crueby

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Re: CHUK2 - Alyn Foundry Flame Gulper
« Reply #78 on: February 04, 2020, 12:44:59 AM »
Ouch!!




Would it be stronger to remake it from some flat steel bar, assuming that the casting was iron? Unless there is more shape I am not seeing on the other side...

Offline cnr6400

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Re: CHUK2 - Alyn Foundry Flame Gulper
« Reply #79 on: February 04, 2020, 01:05:37 AM »
+1 on Chris' suggestion of flat mild steel (or stainless) bar / plate for the replacement crank piece.

 In my experience with cast iron you need some serious beef around the hole for press fits, because it is brittle. A piece of steel is very close to the weight of the iron and will take much more force in press fits before going tango uniform.

I'm sure when the bang happened you said "oh dear" or "son of a beach ball" or "that's awful" just like I would in my shop...... :embarassed:.......... (or wish I did)  :cussing:  Happens to all of us. Better luck tomorrow!  :cheers:
"I've cut that stock three times, and it's still too short!"

Online Jasonb

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Re: CHUK2 - Alyn Foundry Flame Gulper
« Reply #80 on: February 04, 2020, 07:18:59 AM »
Yes another vote for a steel replacement. There is not a lot of metal around that hole, may have got away with it if it were ductile iron but not that hard stuff. I made Chuky's one from round bar but flat would also do.

Infact Graham was thinking of getting some castings done for another engine and I suggested that he did not bother to do castings for a few of the simple parts much like this as it would save costs, risk of hardspots (hopefully not with new foundry) and actually be easier to work.

Online Jo

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Re: CHUK2 - Alyn Foundry Flame Gulper
« Reply #81 on: February 04, 2020, 07:54:36 AM »
I would check your casting I seem to recall something about the pin may be a little close to the edge  :noidea:

I cut my one out of a bit of steel rather than using the castings as the one I had was a little chilled (hard as glass) and I could increase the counter balance size  :)

Jo

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Online Twizseven

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Re: CHUK2 - Alyn Foundry Flame Gulper
« Reply #82 on: February 04, 2020, 09:46:22 AM »
Thanks guys, these things happen.

Jo, you did warn me. I thought I would get away with it.  I think it was due to not enough undercut at the end of the thread and the slight taper as changed to the 4mm dia. forced the casting apart.  Oh well.. Live and learn.

Colin

PS, If I do use another casting at least by the end of today I will have collected a kiln in which to heat treat it.  :cartwheel:  Persuaded the other half she could perhaps have a go at decorative glass making.  Good excuse anyway.  :lolb:

Offline Alyn Foundry

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Re: CHUK2 - Alyn Foundry Flame Gulper
« Reply #83 on: February 04, 2020, 03:44:19 PM »
Hi Colin.

There's a replacement crank web in the post, gone 1st Class, hopefully reach you tomorrow.

Cheers Graham.

Online Twizseven

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Re: CHUK2 - Alyn Foundry Flame Gulper
« Reply #84 on: February 04, 2020, 03:46:15 PM »
Graham,

Many Thanks,

Colin

Online Twizseven

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Re: CHUK2 - Alyn Foundry Flame Gulper
« Reply #85 on: February 05, 2020, 11:18:32 PM »
Graham,

Casting arrived.  many Thanks.

Think my machines are having a war with me.

None of my slitting saws fitted the 13mm arbor for the Aciera, had to borrow one of colleague of mine.  Manage to cut screwdriver slot on big end bolt.

Started to make the  small bits for the valve linkage.  Found I had forgotten to order the 6mm x 6mm brass bar.  Oh well make it out of a bigger piece.

Being as these are only little pieces decided to do them on the Cowells Mill.  This all went well till I fitted a 10mm dia end mill and did not turn the speed up enough.  Large POP and machine came to a halt.  Mains light lit but machine dead.
Quick call to Colin Childs at Cowells to find there is a 5amp fast blow fuse on the motherboard. Yes it had blown.  Luckily I have had a few bags of small fast blow fuses for the last 30 years and never used them, till now.  Fresh fuse and away it went again.  Put smaller cutter in and continued.

Moved to Cowells lathe with the piece of brass (newly fitted with M14x1 spindle) fitted self centering 4 jaw then went to drill with the tailstock.  For some reason it has locked solid, wont extend or retract.  Removed know of leadscrew and removed the tailstock, removed the grub screws and rear knob and the tailstock spindle slides out still with its operating screw thread.  Could not separate them by hand.  Ended up putting the plain shank of the screw part in collet chuck in Myford and used R8 collet chuck from the big mill to get enough grip to separate the two.  Got them apart, cannot get them to screw fully together.  The threads on the spindle look slightly rounded on the peaks.  Need to find out what thread it is and possibly run die down spindle and tap in the tailstock shaft.  That another job come to a halt.

Whats the secret to parting off brass.  Even though on centre it kept digging in and stalling machine


The only upside to the day is I now have a  Paragon SC2 kiln courtesy of Ebay. Another downside was my 98 year old father getting rushed to hospital after a fall at his care home, luckily no broken bones even though he did a forward roll out of his wheel chair.  Silly bugger took his feet of the footrest whilst he was being wheeled to his lunch and somersaulted from the chair.

Colin

Online Jasonb

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Re: CHUK2 - Alyn Foundry Flame Gulper
« Reply #86 on: February 06, 2020, 07:15:54 AM »
suspect you have imperial slitting saws with 1/2" holes.

Get a narrower parting tool, that is a wide cut for a small machine like a Cowells and the relatively "blunt" carbide inserts won't be helping. Either one of the 1.5mm HSS blades in a holder or something like the Mini-Thin inserts if you want to use carbide, I use one of their 1mm wide inserts for all my small parting and grooving.

Online Jo

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Re: CHUK2 - Alyn Foundry Flame Gulper
« Reply #87 on: February 06, 2020, 07:30:40 AM »
That Kiln looks rather nice Colin  8)

I assume this is a "new to you" Cowells and this is the first time you tried using the tailstock  :noidea: later machines are all metric threads...


The rake angle of the parting off tool is much "sharper" for parting off Brass. A Cowells will part off up to 2mm with the right tool but that is a massive width relative to the size of the lathe. I normally use hand ground HSS parting off tools on my Little C.

Jo
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Online Twizseven

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Re: CHUK2 - Alyn Foundry Flame Gulper
« Reply #88 on: February 06, 2020, 09:24:26 AM »
Jason/Jo Will sort out thinner hss parting tool. Will have a look at the minithins.  I do have a narrower hss parting tool but I think I need to remove the rake on the blade

Jo. No I have been using the machine (second user) for about 3 years. It suddenly went solid. It had been working quite happily 3 or 4 minutes earlier.

Colin

Offline Ian S C

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Re: CHUK2 - Alyn Foundry Flame Gulper
« Reply #89 on: February 06, 2020, 12:27:19 PM »
It's possible to make a parting tool from a bit of all hard hacksaw blade, can't remember the thickness you can use either a power hacksaw blade, or hand type. With an all hard blade
take it easy, if it digs in it will go bang, just keep out of the line fire.
Ian S C
« Last Edit: February 06, 2020, 12:32:12 PM by Ian S C »

 

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