Big Earls Farmboy #758

[bigearl91]

Going to give this project thread a little go. If no one takes anything from it, at least it will give me a nice run through of everything I did and the order/process I went through. My last project (Webster) was very much a first go, with a lot of learning and admittedly some impatience. This time I will be taking it much steadier, I also have a much broader set of tools and larger machine tools sat my disposal, and learned a lot since I started this hobby.



Some of the main stock materials laid out. Flywheels not yet purchased, some brass still to buy and crankshaft materials depending on which route I take to construct/machine it.



Whilst I wait for my 6" vice to arrive I decided to start work on the connecting rod. Laziness pushed me down the path of hogging away an pretty oversized piece of 2014A down to the correct size. Maybe I should make a power hacksaw first...



I will be making all critical cuts using the DRO but I still like the reassurance marking out gives. Some of the critical sizes marked, along with the lines to cut the angle between the little and big end. Difficult to see granted due to the Dykem not adhering too well to the machined surface (maybe some contaminants)



Never got any photos, but setup the piece in the vice, shaved a few thou off the big end flat and then wound up the 3.9" to the little end. Drilled, then reamed for 8mm.

Setup using angle blocks in the vice.



12mm end mill with 2mm radius.



One side finished - a little bit of meat left on unintentionally. The depth of cut was determined using the marked line, with the setup and DRO allowing me to just flip it and cut the opposite side identically. I will keep the flats on the little end cutting the radius as the last operation to allow a reference baseline that spans the work piece.


At this point my battery powered garage decided to give up, which where I leave this until next time.

Thanks for reading - my format will probably change as I progress, maybe less words maybe not.
Earl

 

[bigearl91]

Ok so I have never had to think about workholding outside of using a vice, 3/4 jaw and collet chuck so a lot of tonight was spent working out the best way to hold the conrod on the rotary table - which I have also yet had chance to use.

Started out by cutting the other side of the con-rod:


Pretty happy with how it turned out:


I did manage to mess up a dimension but I can adjust if needs be at a later date (also I am aware of the 2 (degree angle on this from cutting with angle blocks):


Little bit more marking out


As I say never had to do this before so did some different trials on the bench first before setting it up in the mill - this setup would never have worked! Which I "soon" realised when thinking through how it would be machined.


Whilst the vice was being removed, a wee touch up with way oil


Another looks at the setup that would have been a disaster:


Centring the rotary table on on the mill - again a first time, took a good bit of time just getting the bleeding dial indicator in a useful position. Hopefully I can leave this up the left hand side of the table and still get my vice back on meaning I won't need to recenter this for a while.


Final setting of the workpiece - used the centre finder and 2 degree angle block again, with the marked centreline as a check, both agreed. Delighted.






Tomorrow I will cut out the web/flange of the conrod and ideally get the little end bearing machined, and see about finishing off the big end, although I think it would be sensible to wait until I finish the crank.


Cheers
Earl

 

[Brian Rupnow]

Okay Earl--I'm watching. When I make a con rod, I generally cut the big end off on what would be the centerline and tap the two holes which will hold the cap bolts. I make the bolt on cap separate, then do the outer profile only. I drill and tap the rod, put clearance holes in the cap, and bolt it on. Then I pick up on the small end diameter, wind the DRO until I've moved the exact center distance, then drill and ream the big end hole into both pieces at the same time.---Brian

 

[bigearl91]

Thanks for your comment Brian,

Much appreciated.

I should add, any tips or suggestions are welcome here. This is only my second project, as much as I learned on the Webster, I am already into unchartered waters so any advice is well recieved. After all something second nature to you guys might take me an hour to work out

Cheers
Earl

 

[bigearl91]

Just another quick hit, nothing major other than finishing off the detail on the con-rod, and now the new vice has arrived squaring up one of the aluminium pieces to begin the frame front. Already filled a rubble sack with aluminium chips. Spending half the time cleaning

First central cut


Rotary table used to match 2 degree taper on external faces. Making sure I was always approaching the rotation from the same direction to eliminate any error from slop in the backlash.


Final cut back to origin - no ovals





Trimmed the webs to design thickness.



Rinse and repeat c'est voila




New toys arrived so I spent a good hour disassembling, cleaning and reassembling. You can see it dwarfing the mill and the 4" Abwood below - although still pretty adequate Z axis remaining. Managed to get it on with the rotary table too. Not able to use X axis all the way to the end of the jaws but it works for the biggest pieces on this build so hopefully can stay as it now.





Now for the frame to begin. I think will pick up the con-rod again once I get onto some lathe work





Quick squareness check showed around 0.03mm variation over the 3.5" squared face which I am more than satisfied with.


Some final checks showed average deviation to be around 0.02mm across the faces. To be honest the surface plate will probably play more a part in this.



I have dug out the big old Enco 3" boring head as I am contemplating fly cutting the finishing cuts. The face mill has given pretty good results so face though.


I will need to research and grind a tool for a good finish on 6082 (6061). I am thinking a very large radius with a high rake? Any advice would be appreciated as again, this will be uncharted territory for me.

Thanks again for reading.
Earl

 

[Rudy from Norway]

Hi Earl,
You will have a good time building this engine. I have just finished my #651. It has been a pleasure to build it. Lots of machining. This was also my second project. I have a thread on my build.
The biggest challenge I encountered was getting the main bearings in line. A reamer did't make it. I used my boring head and went through the bearings WERY slowly. 10 minutes each bearing block. This way I got it straight. My goal was to have the bearings on the crank with no play before clamping it in the block, and still spinning freely when I tightened the bearing blocks. Of cause the crank had to be true in the first place.
I started with a PICTIM ignition, but it died on me (the PIC controller). Probably because of the big car coil I used, don't know. I ended up with building my own ignition driver (have a thread on this too).
I run on propane. I have started to make a propane demand valve after the drawings from Howel. However, I'm modifying the design a bit. Propane seems to be a well suited fuel for this engine. Almost no exhaust and no soot.
I actually run it now on just connecting a hose to the mixer and directly to a butane torch with removed burner. Mot of the gas escapes out in the free, so there is a bit of smell from that. The first run was even simpler, as shown in the video.

An issue I have to go back on is the piston ring. I use some "ordinary" black rubber ring I found laying around, but it lasts only for a short time. I did go back and polished the cylinder to a near mirror finish and it helped. So pay attention to that. I have ordered some Viton silicone rings now.

In the video the noise from the gears is somewhat pronounced. Not that bad in real life. I made the gears with a hand made gear cutter, so there is room for improvements. I have bought proper gear cutters and will make new gears.

I stil wonder how to make some text and graphic on it. Free hand pin striping is not my game. Ordering a CNC carved brass plate at the local lock smith is cheating.

So Earl, I will follow your build and hope you will keep us updated on the progress. So good fun to see such builds brought to life.
For inspiration I put up a picture of mine in a nearly finished state and a link to a video of it's first run.

Rudy

 

[Brian Rupnow]

Earl--I see that you are in the U.K.--do you work in metric or Imperial inches, or does it matter.---Brian

 

[bigearl91]

Hi Earl,
You will have a good time building this engine. I have just finished my #651. It has been a pleasure to build it. Lots of machining. This was also my second project. I have a thread on my build...

Hey Rudy, thanks for sharing this very nice job - I am a fan of the green, and the finish of the base!. I will probably be using the Mini Magneto ignition system - which I used on the Webster very reliably. I actually looked into the PICTIM and its newer/alternate siblings but think in the end I will just stick with the Minimag as for me it is the same thing - I am no electronic engineer - it makes a spark when a switch closes/opens.

As for the rings, I ordered some nitrile "Quad" seal o-rings that I am hoping I will have fortune with. If I wear through them all quickly, I have a heap of Viton rings, and then failing that I will machine some cast iron rings. Fingers crossed the quad seals work - I will be spending some time polishing the cylinder up to minimise wear here.

https://maydayseals.co.uk/quad-rings-/2853-q-020-nitrile-quad-ring.html

Be good to know how you get on with the Viton though!

Earl--I see that you are in the U.K.--do you work in metric or Imperial inches, or does it matter.---Brian

Hmh...
My preference is metric, because I grew up using it and all my tools, drills, taps, dies, reamers (bar a few essentials) etc. are metric. and when I think of a fractional or decimal inch my head converts it to equivalent mm to 'picture the size'

That said, as imperial is so prevalent with this hobby I am starting to get my head round the sizes. Still a [financial] pain with all my tools though.

Something I believe you are familiar with having read your builds is that, it is a given, every different project needs new tools no matter how hard you try to not use any more of those precious beer tokens.

And then of course my lathe's screw cutting gearbox is imperial...

In short Brian - it doesn't matter

Cheers
Earl

 

[bigearl91]

Going to reduce the size of the images as they were a bit overbearing. Nothing too much progress wise as I has some stuff to get sorted and only ended up with a few hours on the tools - a LOT of sweeping and hoovering though.

Stock size compared to finished size - never did go with the fly cutter as these will be coating in a fetching British Racing Green enamel.


No 3rd dimension here but trust me its a big pile - gonna have another 2 like this with the frame read and hopper...


Everything cleaned down again, removed the RT too as for what its worth it was just in the way. Touching off the edges, offsetting 1" and centre drilling for setting up on the lathe.




Then I had a panic as the face mill pattern made it look like I had messed an offset up.... fortunately it was a false alarm - always mark out for sanity's sake!



Ordered the wrong size chuck key for the 4 jaw (not sure where mine has gone) so after some half-arsed grinding, bob's your firkin.



Found some chocolate import aluminium to used for protection against the chuck jaws:


Started setting up the piece as my final task for the day but unfortunately it was lights out before I could finish.



I might end up removing the 4 jaw and sticking the ER40 chuck on to making a test bar to position between a dead centre in the tail stock and the spot drilled point on the workpiece, then using the DTI against that to get the workpiece positioned perfectly (something I believe I read in "The Amatuers Lathe - L.H. Sparey")

It feels a bit like cheating just sticking the DC straight into the centre drilled hole - maybe not? if anyone wants to convince me this is kosher that would be great

Thanks again for reading guys.

Take it easy
Earl

 

[Mago]

It seems this is the month for Farm Boy manufacture and this is another one.
It follows the Jerry Howell design with a few mods.
Couldn't face the machining of the flywheels from CI so made some patterns and had them cast in bronze.
All went well but machining them in a small lathe is a challenge. Spokes need some finishing but this will be done when I have some time and nothing to do.
I decided to fabricate the crankshaft using silver steel for shafts and big end. All the joints were pinned and glued with Loctite.
My engineering experience was before "O" rings and Loctite so decided to forget the fabrication experience and go back to cutting it out of the solid.
I changed the ignition pick up design to provide some advance and retard adjustment.
The oil delivery system to the cylinder is home design and not used when only short runs are made.
In its initial start ups the engine is too stiff to start by hand so a starter is used. Unfortunately it actuates the governor control so that it prevents the motor stating unless it is set for fast running.
This negates the H & M function. More work needed here.

 

[bigearl91]

Thanks for showing interest Mago, I am quite keen to see a wee close-up of your ignition timing setup if that's possible? I like the idea of it however I am keen to use the spark saver option and off the top of my head am thinking it may just require some fundamental changes in the design to achieve both of these features. Have you found it makes much difference in the running of this? being it only hits every so often?

Would love bronze flywheels but £££££££. I found someone on ebay that sells 6" cast iron castings at a reasonable price - I also don't quite fancy machining away that much EN3B/Cast Iron.

I have priced up the 01 flat bar but purposely haven't pulled the trigger on it yet as I haven't made either a proper built up or turned crankshaft yet and will probably go for the built up option as it seems less upsetting (mentally and financially) to bugger up.

Cheers
Earl

 

[bigearl91]

Disaster strikes.

Everything was going incredibly well...lets starts at the beginning.

I decided that I needed a test bar to make certain I had my piece offset correctly. I found some mystery metal with yellow paint on the end. It was vaguely magnetic, the chips were small flakes and it was pretty well formed. Anyway, off with the 4 jaw. On with the ER40 collet chuck. After turning an adequate length down I put a 60 degree taper on the piece. Then reversed and used a centre drill to put the required hole. Any error in concentricity at between each end of the bar these points along this baseline doesn't trouble me.










And the bar in use. between a centre and centre point.




The first cut! no turning back. Had the lathe in back gear at around 300RPM as the balance was an issue - this meant the machining took a lot longer than normal.



Cut the 1.202" thru hole after checking a few times with the T bore gauges I got it cock on


Continued below...

 

[bigearl91]

This puppy has been waiting for its moment!


Measuring up the required depth of cut and setting the DTI





The final cut, again managed to get the diameter cock on and the depth of cut just shy of perfect at 1.803"...... This is where I made a right howler!

Happy with the finish of the bore though.




1.5006" diameter.


Heres the howler:


I was only meant to bore to a depth of 1.355" at dia. 1.5" I have effectively deleted the 1.202 hole (once everything else is machined away)

Really disappointed to be honest. I could make up a ring and press it in, but I don't now if it will have the required strength - I could pin it and loctite it.

Still - shouldn't be making these mistakes, annoyingly I had worked that size out when I started boring but I think I was focussing so much on the diameter being correct, I read the 1.8" and just went for it.

Thanks for reading, any suggestions on what to do to fix this are welcome, I might start again which is a bit of shame.


Cheers
Earl

 

[Rudy from Norway]

I'm a big fan of this Farm Boy engine. I always recommend it. Very well designed. So good fun to make and it works so well. Love sit watching it puff away.
Another tip that came to my mind, the collets for the flywheels. I didn't want visible runnout on the flywheels. Did the flywheels very accurate, but still got wobble. It was the collets. Had to machine both inside and outside before I took it out of the lathe.

Some clever setups Earl. I did my block parts in the mill. Also like your large wise. I have a 6" my selves, and a 4" on the shelf, alone, all day, every day in fact. A big wise is never too big (for the work), but always more rigid.

I will let you know about the Viton ring. Also let us know how your Quad-ring project works.

Mago, I would like some details on how you did the timing adjustment. I plan to make new gears and make the engine rotate the other way. Why? I'm afraid this thing will chop the nose of me. Or an arm. That crank with those two heavy flywheels won't stop rotating if you put something in between it and the frame. Something will give. I also like the strange look of an engine turning the "wrong" way.

I did mine in metric since me and my tools are metric, but I just calculated all the measurements to mm. Lot o extra work and a lot of odd numbers to keep track on. All the bolts in closest metric, easy.
Strangely enough, as a metric guy from birth, I see the logic in the imperial system. Always so easy to splitt or multiply. Metric 10 splitt in half just once and you ar in odd numbers (trouble) already.

Rudy

 

[bouch]

Heres the howler:


I was only meant to bore to a depth of 1.355" at dia. 1.5" I have effectively deleted the 1.202 hole (once everything else is machined away)

Really disappointed to be honest. I could make up a ring and press it in, but I don't now if it will have the required strength - I could pin it and loctite it.

Still - shouldn't be making these mistakes, annoyingly I had worked that size out when I started boring but I think I was focussing so much on the diameter being correct, I read the 1.8" and just went for it.

Thanks for reading, any suggestions on what to do to fix this are welcome, I might start again which is a bit of shame.


Cheers
Earl

My gut instinct is to scrap bin the part and start over. Starting over will make sure you have it right. If you have a questionable fix, you might do a bunch more work just to find out that the piece is junk.

You're really not that far into the work on this part, its not like it was the final hole you drilled in the wrong place. If that was the case, I would try to save it, but you have a lot more work to do on this part.

Sometimes, at the end of the day all you've made is a pile of chips and a piece of scrap. For example, I'm slowly working on a PM Research #5 "Coke Bottle" engine. I made 3 crankshafts before I got one that was right...

Mike

 

[bigearl91]

Thanks for speaking sense Mike!

Oddly, she never has much interest in my hobby but her immediate reaction was exactly what you just said. Why potentially waste more time and then its still a write off!

Now I have done it all once it should be quicker the second time round. Lessons learned! It is only basic machining processes too, some fac milling drilling and boring. Just need to be a bit more vigilant next time!

Cheers
Earl

 

[bigearl91]

I did mine in metric since me and my tools are metric, but I just calculated all the measurements to mm. Lot o extra work and a lot of odd numbers to keep track on. All the bolts in closest metric, easy.
Strangely enough, as a metric guy from birth, I see the logic in the imperial system. Always so easy to splitt or multiply. Metric 10 splitt in half just once and you ar in odd numbers (trouble) already.

Rudy

Yeah im mostly keeping it imperial but it is definitely going to end up a hybrid

 

[Brian Rupnow]

Sorry Earl--I don't know that engine well enough to see what it is that you have done wrong. I have made some amazing "saves" over the years on engines I have been working on. Something you will learn as you build more engines.--Never back up. Once part way into a project and you screw something up---Fix it and carry on.

 

[bigearl91]

I will sleep on it and see how I feel tomorrow. Early start for a big day. Cut today short after realising this error in order to get everything recharged for a big shift. Generating that 440v 3 phase (for the mill) really takes its toll on the setup...

Lets see what tomorrow brings...

Cheers again
Earl

 

[Rudy from Norway]

Making this, and other bar stock engines has that benefit that you can make parts over and over again. My first project, a Stuart 10V built from castings, there where no way back and I was a bit intimidated by that. Did some of the parts on my Farm Boy 3 times... (BTW, the valves and fly wheel collets).
Rudy