Author Topic: Tangler's Air Cooled Farm Boy  (Read 3512 times)

Offline tangler

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Tangler's Air Cooled Farm Boy
« on: April 27, 2019, 05:34:35 PM »
Moving home is an unsettling business.  One exists in a sort of limbo, waiting for the stars to align so that there is a buyer for one's house and suitable property available to buy.  So, whilst this was going on I decided to distract myself with a new project - a Farm Boy from Jerry Howell's plans ( No 585). I had some suitable lumps of ally in stock that were (nearly!) the right size.  I won't bore you with the detail but here are some pics of the roughing out process:













Then the move..and the new house... and the new BIG workshop happened  :)

Moving on 9 months and here we are:

The 2 halves of the frame have a halved lap joint which I crept up on to get a matching fit.  Note that the stock for the front half of the frame was not quite tall enough  >:( but as an oiler is fitted here I am not to worried about that (there's always JB Weld ;) )



Prepared for drilling through the joint



Having obtained a suitably sized ball ended mill the cavity was tidied up



And this is the current status:  screwed together with 6BA screws, not yet glued and awaiting a considerable amount of hand tidying



At some point, and with at least 584 other Farm Boys under construction ( 8) ) I conceived the need for some personalisation and decided to try and make an air cooled version with a finned cast iron cylinder.  Here are a couple of mock ups in Fusion 360





The fins are 1/16" wide at the top and a bit thicker at the base. So, what do you think guys?  Is it a goer?

Cheers,
Rod



Offline Ye-Ole Steam Dude

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Re: Tangler's Air Cooled Farm Boy
« Reply #1 on: April 27, 2019, 05:57:21 PM »
Hello Rod,

Beautiful machine work, keep the photos coming.

Have a great day,
Thomas

Offline b.lindsey

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Re: Tangler's Air Cooled Farm Boy
« Reply #2 on: April 27, 2019, 07:14:07 PM »
Great to see a new project starting Rod. Congrats on the move and new shop also!!

Bill

Online Jasonb

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Re: Tangler's Air Cooled Farm Boy
« Reply #3 on: April 27, 2019, 07:46:29 PM »
As I said before it's a goer. Have you considered a small cooling fan like the air cooled associated engines have, rather than a hefty bracket as has been seen on here recently a boss could be bonded between a couple of fins ( I assume you are turning them) to take the fan's pivot. Then all you need is a of small vee pulliey and a fan cut and twisted from thin sheet.


Offline tangler

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Re: Tangler's Air Cooled Farm Boy
« Reply #4 on: April 28, 2019, 12:04:30 AM »
I like the fan idea.

Thanks,
Rod

Offline Don1966

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Re: Tangler's Air Cooled Farm Boy
« Reply #5 on: April 28, 2019, 12:16:09 AM »
Cool ôRod I am here for the ride..... :popcorn:




 :drinking-41:
Don








Offline b.lindsey

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Re: Tangler's Air Cooled Farm Boy
« Reply #6 on: April 28, 2019, 02:27:49 AM »
Jerry's "Vickie" Stirling engine has a similar arrangement though I did not incorporate it and the engine runs fine and for a long while without it. Farm Boy will no doubt generate more heat. Could be a good addition!

Bill

Offline tangler

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Re: Tangler's Air Cooled Farm Boy
« Reply #7 on: May 02, 2019, 11:01:36 AM »
Thanks for the comments.

This is the plan of action together with the lump of cast iron that (I'm hoping) contains this shape.



The first job was to clean up the outside



I then moved the job to a four jaw for a more secure hold and drilled through with a 3/4 bit, the only drill bit I have with a morse taper shank.



I think using a between centres boring bar is the best way to ensure a parallel bore, even if they are a bit of a pain to set up



Adjusting the tool bit is pretty tricky but I managed to get to 0.998" and there is some light chatter to lap away



Off to Exbury gardens now to look at some pretty azaleas and mayby ride on a steam train.

Cheers,

Rod


Offline Roger B

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Re: Tangler's Air Cooled Farm Boy
« Reply #8 on: May 02, 2019, 02:02:42 PM »
You're off to a good start  :ThumbsUp:  :ThumbsUp: I will be following along  :wine1:
Best regards

Roger

Offline tangler

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Re: Tangler's Air Cooled Farm Boy
« Reply #9 on: May 07, 2019, 03:40:12 PM »




That was a pleasant afternoon.


Since the the cylinder was packed up on the cross slide the the outside is no longer accurately aligned with the bore so I remounted it in the 4 jaw centered on the outside and then  banged the other and around with a hammer till it was centered according to the bore and took a cut along the exterior as far as the chuck.  Then turned it end for end and repeated the process.



Once that was done I turned the register that fits into the end of the frame and started on the fins with a newly sharpened 1/8" parting tool





I turned it end for end again to finish the parallel cutting of the fins because corner of the topslide was interfering with the cylinder.  I've drawn a 2 degree taper on the fins.  Moving the topslide around to 2 degrees means that the topslide handle interferes with the cross slide handle so I replaced it with this little knurled knob which does the job



I changed to a narrower parting tool, cut the tapers down one side and then shifted the topslide to 2 degrees the other way and tapered the other sides.



The top of the fins are 3/16" diameter so I drilled a 3/16" hole in a bit of oil hardening steel (Ground Flat Stock in the UK) then filed away half the diameter of the hole and hardened and tempered.



The bottom of the fins are 1/8" diameter and I already had a HSS tool which I modified on the grindstone to suite



A family shot to finish



Cast iron swarf everywhere so lots of cleaning up to do- including me: Mrs Tangler and I are off to a local restaurant this evening to celebrate our Silver Wedding anniversary.

Cheers,

Rod











Offline Jim Nic

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Re: Tangler's Air Cooled Farm Boy
« Reply #10 on: May 07, 2019, 04:44:37 PM »
Lots of effort to get the "cast" look Rod but it turned out beautifully.
Jim
The person who never made a mistake never made anything.

Offline Dave Otto

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Re: Tangler's Air Cooled Farm Boy
« Reply #11 on: May 08, 2019, 12:59:25 AM »
Great progress Rod, the cylinder looks very nice!

Dave

Offline b.lindsey

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Re: Tangler's Air Cooled Farm Boy
« Reply #12 on: May 08, 2019, 02:11:26 PM »
Looking great Rod, and congrats on the anniversary too!!

Bill

Offline tangler

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Re: Tangler's Air Cooled Farm Boy
« Reply #13 on: May 21, 2019, 02:15:56 PM »
Hi guys,

Sorry for the delay.  I decided to have a go at the connecting rod next.  This seemed like an ideal subject for my little Denford/Sherline CNC mill

I started with a blank of HE15 (2014) aluminium alloy, milled to thickness on the manual mill and with 2off 6mm holes at the correct centre spacing for the big and little end bearings.  This was then mounted onto the CNC milling table and squared to the X axis with a dti.



The Denford software has a simple CAM system that coped with the external profile pretty well



The rest was less successful:  I had to fiddle around with the DXF drawing files to provide pathways that the mill could understand, then it started translating circles into polygons and, to cap it all it decided that it needed to drill a hole in the middle of the web.





The polygon issue has been addressed in a recent update to the software (which, obviously, I have downloaded after the event) and the spurious hole was probably operator error in entering the Z height.  Fusion 360 has a Denford post processor so I have spent the last week or so delving into Fusion CAM.  There's a long way to go so I have decided to carry on with the bit I've made.  The hole could remain as a "feature" - it is at least on the centre line or I could put an ally plug in it.  Anyway, I have tidied up the little end with some filing buttons



I used a boring head in the manual mill to bring the 2 bearing holes to size



The 1/16" oil hole was drilled after spotting with a 2mm end mill



There is quite a bit of cosmetic work to do to make it look more like a forging but I am going to get on with the bearings next.

Cheers,
Rod

Offline tangler

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Re: Tangler's Air Cooled Farm Boy
« Reply #14 on: July 31, 2019, 09:52:51 PM »
Hello again.  OK, I really wasn't happy with the con rod so decided to have a go using Fusion 360.  The CAM package has a Denford post processor.  This turned into a really steep learning curve for me but I managed some sort of result after a lot of trial and error testing with the tool path simulation.  Sadly, it turned out that the Denford software/ Computer/Winows Vista combination I'm using couldn't cope and repeatedly crashed halfway through the program  :Mad:



The next fallback was Manual Numerical Control using the DRO on the manual Mill



The circles represent a 4mm 2 flute cutter centered on the big end bearing.  The red figures are for a 3mm ball end mill.  The plan was to hold a fixture in the vice on a rotating base and shift it 2 degrees either side of the centre line to provide the tapers where necessary.

So, this time around the first job was to drill a pair of holes for the bolts that would fasten the end cap on the big end



The end cap was the slit off



and the holes tapped 4mm in the con rod body while the cap was drilled for 4mm clearance



Centres for the big and little ends were drilled through with a 6 mm spotting drill which leaves a very nice 6mm hole indistinguishable from a reamed hole



The con rod blank was then milled on both side to the overall maximum thickness



I mounted a scrap of aluminium in the vice and mounted a pair of 6mm studs at the con rod bearing centres



The con rod was then mounted on these pins and milling and profiling the shape was undertaken using the coordinates in my drawing



The blank was then flipped to do the other face



The little end was tidied up using the rotary table



I centered the con rod using a length of 6mm drill rod held in a collet



The big end was bored out for the bearing using my boring head: I made a plug gauge to get the size correct



I used the ball ended cutter to break up the corner and make it look a little less like a bar stock engine (is that OK Jason?)