Farm Boy

I should have started this thread when I started the Farm boy hit and miss engine but I did put a few pictures in what I did today thread.

I will put pictures but without all the detail until I get up todate.

Part two If there are any questions just shout from here in I will post as I go The dry fit photos are as of yesterday.

Nice work

H

Looking good.

Steve.

Thank you guys. Not a lot done today except some holes drilled, possibly the same tomorrow.

As above 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.

Today was joining the front and rear base units still need to clean them up the tape was there to prevent getting any epoxy into the threaded holes and any reamed holes.

Then onto the cylinder liner which I got to 0.001" under size which will allow me to polish the bore for the piston to run in.

Blimey your putting my build to shame. Tortoise & a hare. Great work. Looking good.

Steve.

Thank you Steve.

This is not that fast as I started this back in March and this along with the Rob Roy I am building are my first attempts at model engineering.

Cylinder complete all but one hole to drill which is for oiling. Lost count the amount of time I had to clean up luckily I had a magnetic tray in a plastic bag which collected a lot of the swarf, just turned the bag inside out to contain the cast iron swarf without it sticking to the magnet. It was a great slid fit as per the instructions on the plans

After a Saturday at a car rally with my woodturning and a day of rest on Sunday(not because it is a religious day but due to being totally knackered after the Saturday). I returned to the workshop and realised that the liner was sticking out by a very small amount. Not sure why so proceeded to measure and remeasure all of my measurements.

Then it dawned on me I had left a small fillet on an internal corner so back into the 4 jaw chuck and with the parting tool banished it from the piece.

Now that I was happy with that I could set up in the milling machine and drill the oil hole, so now very happy with the liner.

With the two part metal epoxy dry(which I was not happy with got it from Halfords so now ordered some JBWeld) I cleaned up all of the joints on the rear and front halves of the main frame.

Tomorrow I will start on the piston.

No pictures of this silly mistake just a red face for not realising this when turning the liner, well you live and learn which is what I am doing a lot of with this project. It could have been worse.

Today was a slow day I turned the end of a cast iron bar down to 19mm to fit a collet at one end and also a small section of the piston over size so I could reverse it in the 4 jaw chuck. I then reversed the blank in the chuck and turned down the piston to the correct size and faced off, this will be the bottom of the piston. so there is some drilling and milling the bottom as well as a cross hole.
That will be done in a square collet block as the features need to be at right angles to each other. Hopefully that will be done tomorrow as I spent a while getting the piston to a very comfortable fit in the cylinder. As a learner to the hobby like most things it takes a lot longer than a more experienced machinist.
The photos show the piston during machining with a magnetic tray in place catching the cast iron swarf very little ended up on the lathe, will need to turn the bag inside out to contain it. I must buy some plastic bags as the wife keeps on wondering where all the bags are disappearing to

The last couple of photos show the cylinder liner in place. If you look carefully there is a small witness mark at each end this is so I can line up a oil hole in the cylinder with the one in the hopper

Not posted much but realised that I had not posted the progress on the piston all turned to diameter and the inside milled out and hole drilled and threaded. Still need to part off to length and do the piston ring groove when the o ring arrives

Had a very minor mishap on the inside but nothing that would need any more than a little clean up as it I can barely feel the little ridge looks worse than it is.

I did the piston above a few days ago and decided to make the con rod in the mean time while waiting for the o ring.

After two attempts at this I threw the parts in the scrape pile and ordered some replacement ali. Yes two made and both buggered up by me making stupid mistakes

Any way having a day off of the Farmboy I returned today and turned the blank for the head at least that went right after double checking and double checking again was not going to have another con rod episode.

Edited By Dalboy on 27/07/2023 21:34:29

Started on drilling the cylinder head first was the small hole for a post to take the exhaust rocker. Also drill and ream the two holes for the valve guides

Then onto the four holes for the head bolts also while it was there I did a small dimple which will be where the spark plug will go. The reason the spark plug is not drilled yet is that it needs to be at an angle

top and bottom view of the head the dimple can be clearly seen. There are still more holes to drill some can't be done until the valve guides are made and in place

Edited By Dalboy on 28/07/2023 20:41:14

Been working on the valve guides as these need to be inserted in the head before some holes need drilling

Shaped the outside was the first job as well as drill and ream for the valve stems to fit. You can see that the bases are not yet opened up in the second photo.

Changed to a collet chuck so that they can be opened up note the bull nose cutter in the drill chuck to give a rounded bottom to the inside

All complete and pushed into the head. They are not going to move now not only can I now drill some holes into the valve guides from the side but they also will aid in getting the at the correct angle as well allow for lining up the fuel chamber where the spark plug pokes through into the cylinder. As well as this it will aid lining up the angled threaded hole for the spark plug which I spotted earlier on in the head(see previous post)

Slid the valves in just for show, I will fit these properly when I have made some more parts for the head

Except for the spark plug thread which is 1/4" X 32 and I only own a 1/4" X 40 which I seem to have a lot of, so have to order these are ME threads. The head machining is now complete, time to start on some of the furniture for the head like making valve springs and rocker assembly. In the last photo(sorry about the quality) you can make out where the inlet and exhaust ports enter the valve guides. The four holes which can be clearly seen in the bottom of the head photo are for head bolts, the other hole seen in the top of the head is for the rocker arm support and the little hole in the side for a grub screw to lock the support in place.
It seems as if everything turned out OK as closer to completion of the head I was worried that if something went wrong there is a lot of work to get back to here.

Looking good

One point to watch is that glow and miniature spark plugs are threaded 1/4 x 32 UNEF not ME - different angle

In practice, I have found that 1/4" x 32 ME works fine but if you have to buy a tap you may as well get the right one.

Rod

Dalby I have a new 1/4 32 UNEF. hat i bought to do mine I could lend you. Problem is postage will be more than buying one.

Steve.

Thank you Jason for that info it just seems to be missing on the plans. All it said was 1/4" X 32 TPI so I assumed it was ME thread

Edited By Dalboy on 01/08/2023 21:27:24