Farm Boy Hit and Miss engine

[Dalboy]

I mentioned in my other post about a Farm Boy hit and miss engine so I thought I would start a thread just for that otherwise it may get lost in the Rob Roy build.

How this build came about was I managed to get hold of some metal for a very silly price that no one would refuse.
The brass and bronze bars range from just over 1" diameter up to over 2" and varied in length up to 2ft long as well as some ali rounds which again were a good size the piece on the left is 4" diameter and the other bar is a good 2". The other discs are over 2" thick




First job was to saw and machine some of the discs to make three blocks which will become the front and rear base and the larger of the three will become the water hopper and hold the cylinder



After blueing and some marking out as well as the purchase of two 6" flywheels



I took some of the 4" dia ali and made a pulley to fit to one of the flywheels later

 

[Dalboy]

Boring out the front base unit.



The machining the recess where the front and rear base will eventually join. You can just see where I machined the two curved sections one where the hopper will fit and the one facing up is the open end where the cylinder will just fit into



Taking out the material for the con rod will run the crank will be in the rear base unit once complete





A quick and simple turned piece to mount the base so the top curve can be machined





And the final front base unit with the majority of the machining done just a few holes need to be drilled some will have to wait until the rear base is complete as they are for the screws to hold them together.

 

[Dalboy]

This bring me to todays work not had much time so managed to mark out for some of the machining to the rear base.
This is mainly to keep me on track as most of the work is carried out using the DRO.






Starting on the end that will eventually join the front still need to remove more from the two steps as can be seen as I have not reached the lines for these

 

[AndyP]

I had to look up Farm Boy. Glad I did. Fascinating.

 

[Dr.Al]

Looks great. Nice haul of material as well

 

[Dalboy]

I had to look up Farm Boy. Glad I did. Fascinating.

Have a look at this one

https://youtu.be/oEAs7wVTyPI?t=170

Looks great. Nice haul of material as well

Yes I am pleased with the material the yellow and green piece is Phosphor bronze and what I would have had to pay for that the whole haul cost less than that one piece so very happy and the guy was also very happy.

 

[Cabinetman]

Oh yes, always stop and have a look at agricultural shows, I’ve always called them oilers but don’t know why really, but good fun.

 

[Dalboy]

Only had a little amount of time in the workshop but did manage to get the joint done.



With the cutter I used I needed to machine 1" from the centre line but when I offered up the front section as I was machining it slipped on at 1.0021 which I am happy with.



Screws which need to join them together will be done once the two parts are complete they are also aided with some JB Weld

Test fitted






Now to start machining the outsides down to size which have two protrusions on one side and one on the other.

 

[Dalboy]

The rear frame outside machined both sides ready for the centre to be milled out.





A quick test fit to the front frame pleased with the fit

 

[CHJ]

Superb workmanship as usual Derek.
You certainly are giving those new shed boy-toys a run for their money, many a would be modelist would be several years down the line before they were able to exploit their capabilities as well as you have in such a short space of time.

That's really a great haul on the metal stock, amazing the pleasure one gets from just viewing the 'reserves' that find their way into the stock store.

 

[Dalboy]

Thank you Chas. now the weekend is over and having sorted all the bits out from the show, I am now having a day of rest then back onto this build.
I did have 3 requests for teaching woodturning while I was there as well as an inquiry to do a demonstration.
The grass seems to have shot up so that may be the first job.

 

[Dalboy]

Back on the build today as I have been busy with the garden and making a replacement back plate for my collet chuck, pictured with the old thinner one.



I treated myself to a roughing end mill and used that to rough out the rear frame and I am very pleased at how quick it removed material.

 

[CHJ]

Good to see the self help on the upgrade of the chuck mounting :eusa-clap: .
On the subject of cutters; how long before you feel the need for in-house cutter sharpening kit?

 

[Dalboy]

Good to see the self help on the upgrade of the chuck mounting :eusa-clap: .
On the subject of cutters; how long before you feel the need for in-house cutter sharpening kit?

Just buy new cutters as a dedicated sharpener is expensive(Most are only small, cutters that is)

Only had a short time in the workshop today working on the Farm Boy as I was sorting and finishing a bowl which I did a demonstration on yesterday afternoon.

Rear frame main machining complete finished the rear cut out section for the con rod big end to revolve freely. This had to be done at an 8deg angle which made it a little more interesting as well as the centre of the radius needed to be 0.270 down from the top of the rear frame. Still some small holes need drilling as well as the crankshaft top caps need to be made before drilling out for some bronze bearings.





Need to adjust the camera settings as have installed all LED lights in the workshop

 

[Dalboy]

Very little done today found a lump of ali chopped off a piece, squared it all round and machined to final thickness. Cut a piece off the end and cut this in half before machining the other measurements to the final size for the crankshaft top bearing blocks.






I also spent some time cleaning up the inside rear corner which had a little step in it all be it less than 0.005 but still visible and it would have annoyed me seeing it even if it is partially hidden when this is complete.





Still one main large piece to machine then it is onto all the little bits and pieces which should be fun

 

[Dalboy]

I am waiting for some BA fixings so that I can drill some of the holes in the rear section of the frame, so I thought I would start on the hopper assembly well the hopper top at least. The fitting I am using are the closest ones to what the plans state as BA are easier to obtain as well as I already have taps and dies in BA.

 

[AndyP]

Compelling viewing Derek even if I understand so little of what’s involved.

 

[Dalboy]

Compelling viewing Derek even if I understand so little of what’s involved.

Thank you Andy. There is still a lot that I do not understand but am learning plenty as I go along, certainly different than working with wood

 

[Cabinetman]

It all looks extremely impressive, but again to me it’s an alien technology, please don’t let that put you off showing us it all though.
Ian

 

[Dalboy]

It all looks extremely impressive, but again to me it’s an alien technology, please don’t let that put you off showing us it all though.
Ian

Thank you. I will keep posting on this build. Sometimes I do get held up when I need to do some woodwork or having to go out and demonstrate some woodturning

 

[Dalboy]

Machined out the water hopper. by doing this first it will reduce weight for when I machine out the through hole for the cylinder liner which will reduce any tendency to bounce the machine around(not that I think it will be much problem)

I did start on the mill but decided to transfer it to the lathe which is what I should have done to start with as I was getting a better finish to the bottom and also found it easier to get the right dimensions.




A recess was machined for the top to fit which I made the other day I did manage to get it just under 0.002" so a little heat to the hopper should allow it to slide in, that will only happen once all the machining and drilling is complete.

 

[Dalboy]

Over the last couple of days I managed to bore out for the cylinder liner as well as drill three holes to connect this part to the front base unit. I had to do these from both sides as I did not have the correct length bit and using the DRO they lined up perfectly. The forth hole is for a oil passage with a recess for an O ring to seal it when they are bolted together



Marked out for the oil passage down to the cylinder liner



Set up and drilling of the oil passage using a couple of angle plates to set it at 18deg.





I flip the part so I could countersink for some cap head bolts, I did the three holes second drill here as mentioned above. After which reset the DRO to perform a 4 bolt pattern and lightly marked them ready for drilling and threading tomorrow. These are for the head fixing and as can be seen they are quite close to the other top bolt holes

 

[CHJ]

Very neat and well thought out machine mounting as usual, you must have had a field day collecting all the support tooling such as angle blocks etc. you are making use of.

Ohh how I would have welcomed the availability of DRO's 60+ yrs. ago instead of struggling with Vernier dials, slip gauges, dial gauges etc.

 

[Dalboy]

Very neat and well thought out machine mounting as usual, you must have had a field day collecting all the support tooling such as angle blocks etc. you are making use of.

Ohh how I would have welcomed the availability of DRO's 60+ yrs. ago instead of struggling with Vernier dials, slip gauges, dial gauges etc.

A DRO certainly makes life easier especially when doing bolt holes on a circular pattern like the three holes already done as well as for the four head bolt holes when I do those.

 

[Dalboy]

I should be able to continue the hopper assembly after the weekend once the new bolts arrive, in the meantime I turned the inlet and exhaust valves. If they appear slightly different it is not the photo as they are a little different just need to remember when I assemble the engine.

The head is 3/8" across and the stem 1/8" length is 1.5 for the shorter one and 1.560 for the other. I had to turn the stem in three sections to avoid it deflecting when turning. They are stainless steel.

 

[Dalboy]

Eventually got back on the Farm Boy engine.

The two ends are machined to reduce material either side of the hopper section and leave a round boss either end.



Once this was done I placed it on the mill with the intention of just removing some of the material from the bottom curve before mounting it on the rotary table to clean up, but I found that I got rid of the waste with very little clean up needed so rather than set up the rotary table I went down the route of filing the curve and then sand to remove the file marks.

 

[Dalboy]

Today saw a few more holes drilled which enabled me to mount the hopper unit for a dry fit as well as place the rear section. This was after trying to find a tap and matching die for the top hole where the oiler will attach, the mounting holes was not so bad as I had those all ready for that job

As can be seen the hopper unit has all the corners rounded off and the funnel fitted.

 

[Malc2098]

Nice.

 

[Cabinetman]

Most impressive, can’t wait to see the finished thing.

 

[Dalboy]

Thank you both.

One of those days to day not having the right taps and dies for the farm boy so have changed the majority of the fixing sizes to BA as to buy some of the very small sized taps and dies works out expensive when they may not get used again or if they are only once or twice. I have plenty of taps and dies in many forms.
I checked my BA set and found that for some reason the 8BA did not have a bottoming tap which is a must. This was discovered after spending over an hour sorting through all of my loose ones so job one was to sort those out just need to label the box to make it easy to ID which is which.



Now this did not leave much time for working on the farm boy so all that was achieved was this simple square head screw, before ordering more bolts and other bits and pieces. And those that like a laugh I did order some brass balls OK they are for the governor.

 

[AndyP]

How are those two bits joined Derek?
I can see the holes in the flange of the square bit (hopper unit?). Ae they just for some sort of dowel to be glued? Or are they threaded for bolts to go through the hopper unit into the other bit. The other bit appears to be in two halves and is joined. is that just glued?

Must be obvious to some.

 

[Dalboy]

The hopper is attached by three long cap head screws. The front and back will be joined by four countersunk threaded bolts when I have drilled the holes for those, all will become clear when I get to them.
I still need to drill holes in the two base units this will be easier before I attach them permanently

 

[CHJ]

Coming along nicely, hope your 8BA's are sharp, not much margin for excess torque down that small if they bind.

As a matter of interest what grade Ali, are you using.

 

[Dalboy]

Coming along nicely, hope your 8BA's are sharp, not much margin for excess torque down that small if they bind.

As a matter of interest what grade Ali, are you using.

Luckily the 8 BA are only being used for light holding and if they feel tight I can always run a die down them.

The ali was some lumps that were off the end of some large bars so not 100% sure of grade. The piston will be running in a cast iron sleeve which will be the next largest part to make.

This is the end of one which has some writing on it. I got it with a load of brass and bronze and was told it came from an old chap who passed away and was into model engineering. I found a chart and if the colour is to be believed or the company does not use it;s own colouring system then it could be 6082. https://www.parkersteel.co.uk/shared/media/pdf/standards/Colour_Chart.pdf

 

[Dalboy]

The hopper, front and rear frames are now complete all bar the assembly. Managed to complete all the holes including tapping where needed. Tomorrow I will join the front and rear sections with 4 screws and some metal epoxy this will then be the base unit done and I can add parts as i make them.

 

[CHJ]

Another "fingers crossed" stage done, I used to be very nervous of tapping or final engraving stages after a complex machining task in case of a mishap.

 

[AndyP]

The jointing methods are now much clearer, thank you.

 

[Dalboy]

Another "fingers crossed" stage done, I used to be very nervous of tapping or final engraving stages after a complex machining task in case of a mishap.

I am also glad they are out of the way. When tapping I start the tap off while the part is in the milling machine so that the tap is in line with the hole, not under power but turning the spindle by hand enough to get a few threads started then the rest of the hole by hand so I can feel any resistance. Going through the first second and bottoming taps as needed. I hold the tap wrench close to the centre so not as much pressure is exerted on such a small tap.

The jointing methods are now much clearer, thank you.

It will look a little messy when I join it as I will also be using a metal epoxy glue as well

 

[CHJ]

I once had to tap Qty.8 off 12BA holes in Brass to secure a ring flange on an instrument, took me most of a day. Having the week before broken a 1/4" tap in a large lump of brass (waveguide choke) that had taken a whole day to machine.

Nothing like such experiences to instil a lifetimes caution especially when years pass between tackling such tasks.

 

[Dalboy]

I once had to tap Qty.8 off 12BA holes in Brass to secure a ring flange on an instrument, took me most of a day. Having the week before broken a 1/4" tap in a large lump of brass (waveguide choke) that had taken a whole day to machine.

Nothing like such experiences to instil a lifetimes caution especially when years pass between tackling such tasks.

A pain when a tap breaks after so much work has been done, I feel for you.

Even with many years of experience tapping holes (I had to when repairing machines) I still have broken a tap and had the pain of sorting it out as a engine block is not something that anyone would want to replace.
So I am even more cautious when doing fine threads.