Farm Boy hit or miss ( pic intensive )

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coal miner
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Joined: Tue Mar 18, 2008 6:19 pm
Location: Southern Illinios

Farm Boy hit or miss ( pic intensive )

Post by coal miner »

Been working on Jerry Howell's Farm Boy engine for a while now . Have the hopper , base , CI cylinder and piston done . This is slow going for me in that after the first time around on the 2 part base , ..... scrap , Dang . Why is it , it's always the last operation that screws up . Oh well , lots of practice . Also this is learning to make by print . A challenge ! As Harold seys , making to print the first time w/ the proper dimensions consistently is the mark of a good machinist . Well I've got a long way to go , but am learning all the time .
First pic of the engine w/ a fit up of the assembled parts that were made initially . The scales give a sense of size . A lot of 6-32 and 4-40 screws used in these parts .

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This pic shows some of the linkage that controls the valves for the hit or miss operation to work .
The cylinder head was made three times to get it right ! LOL learning . The roller in the brass frame is .125" and the pin is . 062" . Dropped a couple of them . Never found again . The valves have a .250" w/ the stem at .125" . Connecting rod in the back .

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The making of the crankshaft is the project right now . Read everything I could and researched turning between centers , never done that , for info .


Here is a shot of the print for it .

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Received the Starrett 0-1 steel this week and started on it .

Layed out w/Dykem and center holes drilled in each end for the offset turning to get the rod and crank pins the proper throw . . Also roughed out the web for the rod throw on the mill . Hope I don't get to much distortion .

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Figure out how to hold it . Had a couple of doglegs for the Craftsman lathe , found one that would work , but need opened up for the bar . Held it in the milling machine and got enough clearance . The face plate for the 14x40 was a lot bigger , so made a fixture (proper term ?) to drive it .


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Made a 3/16' left and right tool to cut the journals . Alternately skipped back and forth , because of having to plunge in at the middle to get a cut . 260 rpm and .015" cut . Got a rhythm down . Had to take small cuts because of the stick out of the tool , lots of flex .


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Stopped short of the diameter and did a little polishing to see what things would look , will put it back in tomorrow and finish it , about a .100" big . Can't see it , but the journal diam is .4795" to finish at .375" and the width to finish at .550" . Also make the thrust flats and the radius on the web . Then will take it back to the mill to rough out the crank pin , move the centers and start on that portion . I'll have to make a . 576" spacer to support the throw on the crank pin to keep everything right .


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Learning a lot on the project about making to print . One thing I've learned is to slow way down and make sure it's right .
The more I learn , The more I don't know !
Russ Hanscom
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Re: Farm Boy hit or miss ( pic intensive )

Post by Russ Hanscom »

Nice work, looks like a fun project.
JackF
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Re: Farm Boy hit or miss ( pic intensive )

Post by JackF »

Coal Miner,

Great job so far. Love the pic documentation, please keep us informed on the progress.

Jack.
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GlennW
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Re: Farm Boy hit or miss ( pic intensive )

Post by GlennW »

Great project, and great job so far!

Please keep us updated.

Thanks!
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!
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coal miner
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Re: Farm Boy hit or miss ( pic intensive )

Post by coal miner »

Finished the crankshaft to day . Satisfied w/ the out come . Set it up in some V-blocks and came up with .001 run-out , hit all the specs OK .

Got the crankpin journal done , milled out the excess on the crankshaft ends and one side roughed out to .025" over . Then flipped end for end and started on the other side of the shaft journal . Unequal lengths on the shaft portion , also allow for the thrust faces .

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Made a split block out of AL to clamp around the journal in the dog leg driver so the shaft wouldn't get scarred and a spacer to keep the center the proper dimension .


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Hit the diameters on the pin and shaft portions within a couple of tenths . .375" on the pin and shaft journals , .0625 x .032" thrust faces . All polished up .


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Have to order some phosphor bronze for the split bearings and bore the mains on the engine block . I'm thinking that once the split bearings are made any adjustment will be easier to control when boring the body in the mill . I'm all ears if anyone can guide me on this split bearing thing . I would like to babbit them but don't have a clue how to do that . I have 2 sets to make . One for the rod bush and one set for the crankshaft . Got lots of little parts to make to keep me busy while waiting for the bronze to get here . One thing about the O-1 Starrett bar , it is hard . Chips came good , but too much speed or feed and the radius of the tool grew real quick . The straw color changed to blue real quick ! Spent time keeping every thing sharp . Of course the interrupted cut didn't help either . One question on live centers . I have seen extended point types , sometimes called CNC , in the catalogs . Are they as good at holding as a regular live center ? They would give me more room for the cutting tool and not have to grind clearance on it . Have several carbide tool holders that won't let me get to the end of small shafting without doing a regrind in the tool end . Maybe this would solve that problem .
The more I learn , The more I don't know !
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GlennW
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Re: Farm Boy hit or miss ( pic intensive )

Post by GlennW »

I prefer the CNC type live centers for use on my lathe for reasonns of greater tool access, as you mentioned.

They are a bit more expensive for a good one, but I feel they are worth it.

They most likely have a lighter weight limit than a standard live center, but that is not a factor for me.

If you really need access nearly up to the center point, try a carbide tipped half center.
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!
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coal miner
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Re: Farm Boy hit or miss ( pic intensive )

Post by coal miner »

Flywheels done . Set up the rotary table with the cast iron blanks which had been machined to size . 6 spoke .400" wide . All the calculations had been done by Mr. Howell , but getting the cutting done was a major accomplishment for me . Dialing in the wheel the first time proved to be a big learning process . Getting it concentric on the table ,then centered under the spindle with a co-ax indicator brought the wheel to being dialed in .

As received .

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Turning the wheels to size w/ proper relief on the rim and hub dimensions . Ways covered to keep the cuttings off of them .

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Check on run out .

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Finished and ready for the RT .

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Please forgive my set up as I didn't have some 6" pipe for the clamping so used what I had until the pipe came in and a proper fixture could be made .

Cutting the slots in the outer radius . web thickness .300" . The paper was used for shimming to get a secure clamping to the 123 blocks so it would be solid . 19 degrees between the 41 degree slots , just crank the RT wheel and keep track of the degrees.

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Next was to set over .200" and connect the one side and then set over from center a - .200" to cut out the other side of the triangle piece .

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Finished , the second one with a better spacer .

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Two good ones the first time around .

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1/8" key ways to be yet cut and a taper w/ matching collets made to bolt to the 4-40 holes to secure the fly wheel to the crankshaft .
One observation that I have made is that real estate on the jig plate gets scarce quickly and cast iron eats HSS lathe tools . Resorted to carbide to turn the wheels , suspect I had the wrong feeds . The HSS end mills gave a beautiful finish .
The more I learn , The more I don't know !
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steamin10
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Re: Farm Boy hit or miss ( pic intensive )

Post by steamin10 »

I dunno. My screen shows some distortion. Probably due to light levels, picking up glare.

Typically at the corners newbe errors show up as overcuts and slight bumps at the end of the cuts. You have done well, keeping things sharp and the setup right. Are you using a pad and pnecil, to write down your repeat marks?

I am jealous, I cant do any work like that right now as my new rotab was stolen some months ago. Looks good, so nice job.
Big Dave, former Millwright, Electrician, Environmental conditioning, and back yard Fixxit guy. Now retired, persuing boats, trains, and broken relics.
We have enough youth, how about a fountain of Smart. My computer beat me at chess, but not kickboxing
It is not getting caught in the rain, its learning to dance in it. People saying good morning, should have to prove it.
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coal miner
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Re: Farm Boy hit or miss ( pic intensive )

Post by coal miner »

steamin10 wrote:Typically at the corners newbe errors show up as overcuts and slight bumps at the end of the cuts.
Dave , I thought about that and stopped about 10' short of the finished cut , LOL . I kinda figured that might happen . Not being trained properly makes one cautious in respect in removing metal , so I go back over , to the finished dimensions , to get it right the second time around . Just like the finish cut on the lathe or mill . The outer radius had .157" corners and the radius at the hub was .187" .Took three cuts to get thru the .300" web so no chatter . Still took some massaging with the Dremel and a flap disc to get things blended . Finding more uses for it all the time , as it is easier to handle than the die grinder .
steamin10 wrote: Are you using a pad and pencil, to write down your repeat marks?
You betcha ! Also used Dykem and touched the rim to check the numbers twice thru the circle to make sure . Glad I'm not doing this for pay . I'd starve to death ! Slow and be sure . At least I'm not making as much scrap , those chunks of cast iron were $ 16.00 a piece . So much to learn about a RT . Thanks for the complement .
The more I learn , The more I don't know !
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steamin10
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Re: Farm Boy hit or miss ( pic intensive )

Post by steamin10 »

Well this puts you ahead of me, I have never done such spokes on a round. Just bought a rotab last year, and its gone from theives. People that get close to you, not strangers.

The reason for asking the questions is one of displaying the workings of getting it right. When I work on the lathe I am always scribbling on 3x5 file cards or a legal note and sketch pad to incorporate ideas or warnings about snags in the process.

When you and I get to making dust and chips, if you dont spend the time to get it right, how can you afford the time to do it over?

If you find that the melding of cut and polish lines a bit obvious, light media blasting can even up the look with the texture, before paint. I like the effect, but dont always use it.
Big Dave, former Millwright, Electrician, Environmental conditioning, and back yard Fixxit guy. Now retired, persuing boats, trains, and broken relics.
We have enough youth, how about a fountain of Smart. My computer beat me at chess, but not kickboxing
It is not getting caught in the rain, its learning to dance in it. People saying good morning, should have to prove it.
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coal miner
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Re: Farm Boy hit or miss ( pic intensive )

Post by coal miner »

Got some time in the shop this last week despite the cold temps . ( supposed to be in the 50º's and low 60º's this week ) I had already made the crankshaft bearings so now to make the con rod split bearing . I had some 1" phosphor bronze that was turned to .900" then split in the band saw . After milling the saw cuts smooth , soldered them together . The round now became an elliptical shaped piece and was a problem to hold in the big chuck . Have 4" 4 jaw that is on a 5C and , using a 5C block , dialed it in as best I could in respect to it's shape . Rough turned the OD and then drilled the ID under , bored to .376" . All good to go on the OD . First cut the piece came out of the chuck and landed in the chip pan in two pieces . Ugh , oh darn ! Took the 2 peices to the bench and instead of re-soldering , used super glue and very carefully glued them back together . Took a very light ( tenths ) cut on the ID and every thing looked good , so finished the OD . Another piece of scrap saved . Glad the glue held .

Being held in the little 4 jaw .

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Time for fit up to see if the dimensions were right . The rod halves were assembled and bolt clearances milled , also oiling hole drilled thru insert can't see it here .

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Polished the rod throw down to 2000 grit and the rotating assembly all together .

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I have no aspersions to emulate some of the most excellent work done by other members on this site , but their projects show me what can be made . It inspires me to improve my abilities .

Now to bore the crankshaft journals to size in the frame .
The more I learn , The more I don't know !
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coal miner
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Re: Farm Boy hit or miss ( pic intensive )

Post by coal miner »

What kind of mandrel to use to hold the gear blank ? Just received the involute cutters ( 48 DP , #2,#3 ) for cutting the gears for the Farm Boy . No problem with the mandrels for them , 12L14 and made in one piece on the lathe - 3/4" shank and .875' diam. for the cutters w/ 1/8" keyway and .300" washer tightened with a 5/16"-24 SHCS . Now the problem of holding the blank . IIRC the large gear is 1.542" x .156" face width w/a .375 "reamed center and smaller is to be .792" diam . x .187 face and .375 " reamed center hole . 72 and 36 teeth respectively and no keyway . The spin indexer could be used for this , I guess , but I want to use the RT as I feel it has more accuracy . I have a MT center for the RT and tail stock and use a dog to drive everything . I"m thinking of some kind of expanding arbor that could be made on the lathe . Also would the dividing plates be more accurate ? Thanks in advance .
The more I learn , The more I don't know !
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