Stuart 10v

[swarf]

Hi "swarf". Just a reminder... so you do not drift into bad practices..
This thread is all about Model Engine Machining. So really you should machine precisely to the right size, then instead of the approach of "a tight fit and wear it in" you start at "the right fit - first time" - which curiously lasts much longer than the "worn-in" method. - Which is why "Industry" has spent a small fortune working to finer and finer tolerances so your car (and other modern "necessities") has become relatively cheap, Incredibly durable, and maintenance free for a long-enough life.
When I started (around 1966) in a machine shop doing re-bores and crank regrinds, the NORM was for every petrol engine to need new rings or small re-bore after 10,000miles, but a larger re-bore if it had been run for 20,000 miles... Cranks lasted 20.000 miles before a re0-grind to first oversize. - NOW it is 150~250.000 miles before any sign of significant wear on the bore, and more of wear on the crank.
All this achieved by making parts true, and closely fitted "as new".
SO I suggest that having reamed the bearings all in one in-line, there is actually a difference between the size of reamer and crankshaft main bearing journals. - Or possibly some misalignment of the crank main journals. (because the set-up can distort the crank.. leading to journals machined on that set-up to become out-of-alignment when the set-up stresses are released).
If you reset the crank in the lathe, between centres, then put a DTI along the journals, you may spot the "bend" of the crank between journals. BUT you will need to pack between the flanks of the crank in order to NOT distort the crank when you fit the tailstock centre. use Engineer's blue (of felt-pen marker) on the journals and recheck the "touch" point of the lathe tool on all journals. It should be at EXACTLY the same setting on the lathe dials. Then when you are absolutely sure that the crank is NOT distorted in any way by the set-up, just "touch" any high-spots of the crank main journals with the tool while the part is rotating, to "true" the journals to a sizes that is less than 0.001" than the micrometer measures the reamer you have used. - Remember if it is a tapered reamer, the first 1/3rd will be under sized as it has a taper for starting the reaming process. Making a true and straight shaft the fits the true and straight bearings (reamed in line) is the key to a smooth running - from NEW. The adage "Wearing -in" is truly "ACCELERATED WEARING-OUT" the engine, I.E. giving the finished engine a short life from a worn-out condition. It is really a bodge to overcome deficiencies in the manufacturing process.
However, there is a process of "LAPPING" - This uses VERY fine abrasives, to "grind-off" the peaks of machines surfaces, - but not remove more than the amount necessary to make a finer finish than the machining tool can do. This is best described by the HONING process on bores, where a precision set grind-stone, of grit much finer than the cutting pitch of the tool that was used for boring, is used to take off the "Peaks" from the machined surface to leave 50 or so as a rubbing" surface, and 50% or so for "storage of oil". (Not exactly true but the simplest explanations are often not quite true).
View attachment 139117
I hope this sketch helps?
As long as the crank measures "true" (straight and parallel at the journals with the DTI) and "SIZE" (same as the reamer/bearings) then you can remove tightness by linishing "high-spots" where the bearings can wipe-off the marking blue, when assembled and rotated.. But check it is crank or bearings that need the linishing! Use the shank of a drill, reamer, length of silver-steel or equivalent test bar, at the size of the crank journal, fit it into the bearings, - duly tightened - and rotate to the bearings, and rotate to see if the bearings are "wiped" all the way around and all the way along. If you get a line "top and bottom" of the split bearings, this indicates a bearing that is not round when clamped. If you get a wiped circle at one end or the other of the bearing, then it suggests the bearings are tapered. If you get odd, diagonally opposite wiped zones, the bearings are not aligned. Only when the bearings are good with a test piece should you look to the crank. By "Wiped" I mean the Engineers' Blue has either transferred form one surface to another, or been wiped off a surface, indicating the contact points between shaft and bearing surfaces, within the bearing.
Equally, on the test shaft - and again with the crank, - the contact point should tell the same story.
Depending of "shaft journal size" and "bearing size" you can decide if the shaft needs reducing (linishing) a tiny amount to fit the reamed bearings, or if the alignment of the bearings needs addressing. (Re-set to a true test-bar, not the reamer's cutting edges, or crank).
I hope some of this helps?
Ask where you want more explanation, as there are many more capable than I who can advise or correct any errors I have made. (I learn as much as I teach!).
Cheers!
K2
On the crank, the

Hi swarf. As I recall I experienced a similar issue. The base of the bearings only need to be a fraction of a thou out to cause the crank to run tight when the nuts are tightened. I think I placed a shim (kitchen foil) under one of the bearings to get the crank to run freely.
Experiment and give it a try.
Cheers
Andrew

Thanks for all your help.
Steamchick sometimes I get to the point where I've been working on something long enuf and then start taking short cuts and want to get to the next step.
So I chucked a hand reamer in the drill press held the part and
ran it through a couple times.
Then bolted everything back together and it was still stiff, better but stiff.
Proceeded to chuck the assembly in the lathe to further break in the bearings. The friction was considerably less with no play in the shaft. However the oil I put in the journals was flying out on the crank as fast as I put it in.
Conclusion, as you mentioned Steamchick wearing in is also wearing out.
The bearing will suffice but it's not right, so I ordered new bearing material and round stock for the center crank.
Andrew,
as you mentioned I had some shim stock in my garage. The thinnest I had was 3 thou. Unfortunately to thick.
I imagine aluminum foil would be thinner, but as mentioned the damage was done. Oil runs through the bearing and even though there's no appreciable play in the shaft, it will only be a matter of time before it starts rattling like a pneumatic drill.
Love your builds keep up the good work.
Humble has been eaten and will start over.
Thanks both of you.

 

[AndrewW]

Thanks for all your help.
Steamchick sometimes I get to the point where I've been working on something long enuf and then start taking short cuts and want to get to the next step.
So I chucked a hand reamer in the drill press held the part and
ran it through a couple times.
Then bolted everything back together and it was still stiff, better but stiff.
Proceeded to chuck the assembly in the lathe to further break in the bearings. The friction was considerably less with no play in the shaft. However the oil I put in the journals was flying out on the crank as fast as I put it in.
Conclusion, as you mentioned Steamchick wearing in is also wearing out.
The bearing will suffice but it's not right, so I ordered new bearing material and round stock for the center crank.
Andrew,
as you mentioned I had some shim stock in my garage. The thinnest I had was 3 thou. Unfortunately to thick.
I imagine aluminum foil would be thinner, but as mentioned the damage was done. Oil runs through the bearing and even though there's no appreciable play in the shaft, it will only be a matter of time before it starts rattling like a pneumatic drill.
Love your builds keep up the good work.
Humble has been eaten and will start over.
Thanks both of you.

Hi swarf. Don't beat yourself up over it. It's all about learning and the best way to learn is from making mistakes. Having moved on to making engines from bar stock, I would explore making the crankshaft bearings from mild steel bar and reaming them to fit some home made bronze bushes. It shouldn't be that difficult and if you make a mistake you can just start again with some readily available material. Get some 9/32" dia mild steel and set the bearings up using that initially.
It's a fantastic and rewarding hobby and it's amazing what can be achieved in the home workshop. Enjoy the journey!
Cheers
Andrew

 

[AndrewW]

Thanks for all your help.
Steamchick sometimes I get to the point where I've been working on something long enuf and then start taking short cuts and want to get to the next step.
So I chucked a hand reamer in the drill press held the part and
ran it through a couple times.
Then bolted everything back together and it was still stiff, better but stiff.
Proceeded to chuck the assembly in the lathe to further break in the bearings. The friction was considerably less with no play in the shaft. However the oil I put in the journals was flying out on the crank as fast as I put it in.
Conclusion, as you mentioned Steamchick wearing in is also wearing out.
The bearing will suffice but it's not right, so I ordered new bearing material and round stock for the center crank.
Andrew,
as you mentioned I had some shim stock in my garage. The thinnest I had was 3 thou. Unfortunately to thick.
I imagine aluminum foil would be thinner, but as mentioned the damage was done. Oil runs through the bearing and even though there's no appreciable play in the shaft, it will only be a matter of time before it starts rattling like a pneumatic drill.
Love your builds keep up the good work.
Humble has been eaten and will start over.
Thanks both of you.

Another thought.... Bolt your existing bearing blocks together, side by side, onto a piece of flat bar. Drill and ream both at the same time to take a piece of bronze, making sure the bar is exactly perpendicular with the mill spindle. Use loctite 638 to secure the bronze. Drill and ream the bronze to take the crankshaft. Split with a hacksaw and tidy up with a file.
Cheers
Andrew

 

[Steamchick]

Hi Swarf, I fully endorse Andrew: don't beat yourself up about it... Just say "OK, I have learned that lesson, now lets see if the guys that have been there and done the same, have better ideas that really work. And if they do work, we are the lucky ones for making the right suggestions!
"There are more ways of killing a pig, than you could imagine, and some die naturally" !! The wearing-in, wearing-out game can work... but more likely to lead to shorter life. Well done for trying.
Incidentally, I run lots of peoples' models at shows, and an odd few complain because their beautiful models are all oily afterwards,... But I ask before I run them, and do my best to not wear them out. I won't run without oil, and it does go everywhere! No-one has oil seals on such small engines. Just keep a good (cotton) rag to hand, and wear overalls when running, not "smart" clothes.
K2

 

[Drawfiler]

Swarf,
The first engine I attempted was a 10 v, this was while I was at school, the only kit we had in the workshop was a Myford Ml7 and old Drummond and a drilling machine, all milling and boring was done in the lathe either with the casting in a 4jaw, on a face plate or clamped to the cross slide. Take your time, think the setups through and enjoy yourself.

 

[swarf]

Figured out the problem. I thought for sure it was the bearings or the crank.
400 wet or dry and a piece of polished granite is a great thing to have.
As it turns out there was 1 thou difference on the bearing pillars on the sole plate on either side.
It was the last thing I thought of in my list of potential problems.
Took a chance and finely ground all machined surfaces on the sole plate with 400 wet or dry and some cutting oil.
Low and behold everything turns as it should.
This is an awesome hobby.
My mill/drill (more drill than mill) is a round column machine and there are only 4 cap screws to hold the column to the machine base. I managed to shim the worse of axis but the other isn't perfect. May have to shim my mill vice to compensate.
It's not a great machine but it's better than none at all.
The thing has grown on me and I wouldn't trade it for the world. Got it brand new from a guy who used it once for 500$ couple years ago.
It does what I need it to do and that's all I'm worried about.

 

[AndrewW]

Figured out the problem. I thought for sure it was the bearings or the crank.
400 wet or dry and a piece of polished granite is a great thing to have.
As it turns out there was 1 thou difference on the bearing pillars on the sole plate on either side.
It was the last thing I thought of in my list of potential problems.
Took a chance and finely ground all machined surfaces on the sole plate with 400 wet or dry and some cutting oil.
Low and behold everything turns as it should.
This is an awesome hobby.
My mill/drill (more drill than mill) is a round column machine and there are only 4 cap screws to hold the column to the machine base. I managed to shim the worse of axis but the other isn't perfect. May have to shim my mill vice to compensate.
It's not a great machine but it's better than none at all.
The thing has grown on me and I wouldn't trade it for the world. Got it brand new from a guy who used it once for 500$ couple years ago.
It does what I need it to do and that's all I'm worried about.

Result!

 

[Apprentice707]

These 10 V & H Stuart Engines can't be rushed, I received a set of castings from my parents for my 12th birthday (cost 12 shillings and 6 pence) and I finished it when I reached 64. It traveled with me to 3 continents and was on my New Years' resolution list every year. Stick with it guys it is worth it!!

B

 

[packrat]

Yes, it took me 3 years to finish a Stuart beam engine, just working on it when I had some time...

 

[awake]

"There are more ways of killing a pig, than you could imagine, and some die naturally" !!

I hadn't heard that quote before - love it!

Incidentally, I run lots of peoples' models at shows, and an odd few complain because their beautiful models are all oily afterwards,...

I think the proper response: "Well oil be damned!" (Hint: the pun won't register in print; you have to think about how it would sound, especially with a bit of a Cockney accent.)

 

[swarf]

 

[Richard Hed]

I'm still working on a Coles/Ray Corliss after 40 years or so. Made a bit of progress, however, milling parts is difficult. Turning is fine but I managed to get a mill, but have a hard time getting the $$ for a VFD for the 3 phase motor. Will manage it this summer however. (What summer? it's still very cool here in Moses Lake.)

 

[Bentwings]

Hi Swarf, I fully endorse Andrew: don't beat yourself up about it... Just say "OK, I have learned that lesson, now lets see if the guys that have been there and done the same, have better ideas that really work. And if they do work, we are the lucky ones for making the right suggestions!
"There are more ways of killing a pig, than you could imagine, and some die naturally" !! The wearing-in, wearing-out game can work... but more likely to lead to shorter life. Well done for trying.
Incidentally, I run lots of peoples' models at shows, and an odd few complain because their beautiful models are all oily afterwards,... But I ask before I run them, and do my best to not wear them out. I won't run without oil, and it does go everywhere! No-one has oil seals on such small engines. Just keep a good (cotton) rag to hand, and wear overalls when running, not "smart" clothes.
K2

I had a big twin big block Chevy powered boat. I rarely wear shorts . One day it was really hot out on the water so I cut the legs off an old pair of jeans and saved them for rags. It happened to be oil and filter change time add dual filters every where and new bilge pump install getting below decks in a big inboard boat is quite different than outboards the transmissionsvarevwaybundervthe deck like being in a dub . It’s not cool below decks even with the engines cooled down . By the end of the day I looked like a real grease monkey and had the disposition of a gorilla ! I had 40+ gallons of oil 8 filters and misc other junk to recycle my little el Camino was near overload. They woul not take the filters as I didn’t buy them there so I had a special trip to the auto parts store to recycle them . With all the fluid change I didn’t get any in the bilges . They get algae and mold so I had to use a special bio cleaner for them . It nice when you are all done with a nasty job. It. Lived n the boat for two years my dock mate had a bigger boat with twin cat diesels. I YHINK each had around 10 gallon engine oil dumps and twice the size filters I had . He had an automatic oil changer. He just rolled a 55 gallon barrel out on the dock an stuck the drain hose in it then turned the auto drain pump on So less of a mess but we had to use my one ton dusky to haul his recycle stuff I think his air filters were over$100 each 4 of them his oil filters were huge too.

Big boats are fun but lots of work . Another dock mate had outboards he managed to forgectonputvyhecdrain plug in and nearly sank his boat . Here if you trailer boats you have to drain the bilges when you take them out prevent transferring unwanted marine creatures and plants from waterways . It’s common to forget the drain plug

 

[Steamchick]

Awake: I can't imagine a Cockney accent by someone from North Carolina... Except maybe the Dick Van Dyke portrayal of a Cockney chimney sweep in the 1960s Mary Poppins? I think the English version of the quote is "Whale oil be dammed!" - A Victorian phrase, before "Well oil" was commercially available?
Sorry, I'm pulling your leg. Just playing with puns...
Now "Darn my picters!": Did anyone expect Mary Poppins to appear in this engineering thread? - Sorry if too far off beam.
K2

 

[swarf]

 

[methuselah1]

You were only supposed to blow the bloody doors off!

 

[swarf]

Well here it is, not a quite a year later and I've made some progress on my engine.
I left off with oversize bearings but have since corrected the problem on the casting and machined new bearings. Moved on to the piston and piston rod.
After machining the piston I now have a two and a half thou piston to cylinder wall clearance.
Question is this going to be excessive? The piston is brass the cylinder cast iron.
What kind of clearance should I be looking at ?
I intend to use graphite yarn packing for the "rings".

 

[Steamchick]

Hi Swarf.
Here is the Enginineering bit that goes with Machining in the title of the website.... (My corruption of "Engine" - You can't have an Engine unless it is Engineered!

Aside: Engineering comes from ancient Greek for Ingenuity... I.E. the application of Ingenuity to solve problems is Engineering. And engineering is an Ingeneous device to convert energy in one form to another form. Boiling water from a "low pressure heat source" to make steam at a "high pressure gas supply", or expanding that hot steam into cooler water and developing a mechanical force on a piston. Both of these are "Heat Engines".).
Back to your problem:
Brass expands at:
"the coefficient of linear expansion of brass is 0.0000189 per °C." - So for 100 deg. C temperature rise it will expand a 1" diameter piston to 1.00189" - nearly 2 thou expansion.
Cast iron, on a 1" bore expanding 100deg.C. has "the coefficient of linear expansion of cast iron is 0.00001 per °C." - So it will expand to 1.001" = 1 thou expansion.
Therefore you need 2 - 1 = 1 thou clearance. ( or may be 1.5~2 to be sure and so you can hear the piston slapping about?).

I suggest you tin plate the piston skirt with a "lead-wipe" of Tin based solder.
I.E. flux the piston, tin it with solder, and while the solder is HOT and liquid, wipe it quickly with a dry leather cloth (Chamois leather is OK). WEAR GLOVES so you do not burn your hands! SKIN BURNS AND HURTS when touching metal as hot as molten solder. But this is how Plumbers made their soldered joints before factory pre-soldered fittings were available.
Then check there are no blobs or high spots of tin solder on the piston, and mic it to see if it needs linishing to size, around 0.001 to 0.0015" smaller than the bore - if it is a 1" diameter piston. (Linishing can be simply done by someone skilled and careful, using a file, but only as a rigid flat holder for a very fine emery paper to take off the tiniest amount of solder to reduce the diameter by a fraction of 0.001", while turning the piston at only 100~200rpm or so in the lathe).
I expect this tinning technique to increase the diameter of the piston by something like 0.0005" either side = 0.001" diameter.
The tin-solder in application in the engine is good for maybe 130 deg C - and I doubt you'll be doing enough work with the engine to need over 30psi steam!! (3 ~5 psi more like if just idling!). The tin is also a good bearing surface to slide in the bore.
Or you can make a new piston... with 0.001" clearance.
Of course, if it is a 2" bore engine then the clearance is about right...
But be cautious, measuring fractions of 0.001" requires very good measuring equipment and technique... Often not available to the Home machinist! (re: controlled temperature, slip gauges for calibration, etc.).
Take 10 measurements of the piston diameter, putting everything (piston, measuring tools) on the bench and turn around every time. Then do some statistics to see if you can measure the same thing repeatably. And I don't mean "can you repeatably turn the knob on the micrometer to the same number every time". I mean will the micrometer give you the same reading every time you pick-up it and the workpiece, and measure the part? Some micrometers have a vernier calibration around the barrel to achieve 0.0001" increments, but I am not that repeatable! And how repeatable are you at measuring the bore? Usually dial gauges to measure bores need to be set to the micrometer.. Set the micrometer to the piston diameter +0.001". Insert the bore gauge to the micrometer and set its DTI at zero. Compare this to the bore and see what size it really is... I was doing this at 12 years old, but all my work was double checked until I was 14 or so and was allowed to re=bore and hone engine blocks for cars on my own...
Give me a thumbs up if that makes sense to you? - Or I can accept a thumbs-down and corrective criticism from anyone who has more expertise than I. - Let's get it right.
K2

 

[Steamchick]

Piston rings.
You can make (or BUY!) cast iron rings, steel wire rings, Viton O-rings, or PTFE.
PTFE is really good - but with all materials - including simple cast iron - wear breathing protection (a face mask, like for COVID) to avoid breathing-in any dust. Almost anything will clog lungs affecting later life, and some things, like carbon from machining cast iron (especially when it just looks like a bit of smoke off the tool) is carcinogenic, so worth avoiding. PTFE and some plastics give of nasty toxic fumes in certain conditions, so simply take the usual precautions. or "Buy" these cheap and precise little components.
Graphited string works fine on my engines, but is a bit of a fiddle to get right. Not too much = tight, or too little = doesn't seal effectively.
And I have some engines with just labyrinth seals. = a few grooves with sharp square corners. e.g. 0.020~0.40" wide and deep and spaced.... (I make grooving tools from hacksaw blades). These prevent gas flow dynamically, so 8 is the maximum number of grooves, but even 1 works OK on a simple steam engine just for bench idling. - e.g. (d) below:

You can use just grooves in the piston and a smooth bore which will be OK.

Hope this helps?
K2

 

[Richard Hed]

Hi Swarf.
Here is the Enginineering bit that goes with Machining in the title of the website.... (My corruption of "Engine" - You can't have an Engine unless it is Engineered!

Aside: Engineering comes from ancient Greek for Ingenuity... I.E. the application of Ingenuity to solve problems is Engineering. And engineering is an Ingeneous device to convert energy in one form to another form. Boiling water from a "low pressure heat source" to make steam at a "high pressure gas supply", or expanding that hot steam into cooler water and developing a mechanical force on a piston. Both of these are "Heat Engines".).
Back to your problem:
Brass expands at:
"the coefficient of linear expansion of brass is 0.0000189 per °C." - So for 100 deg. C temperature rise it will expand a 1" diameter piston to 1.00189" - nearly 2 thou expansion.
Cast iron, on a 1" bore expanding 100deg.C. has "the coefficient of linear expansion of cast iron is 0.00001 per °C." - So it will expand to 1.001" = 1 thou expansion.
Therefore you need 2 - 1 = 1 thou clearance. ( or may be 1.5~2 to be sure and so you can hear the piston slapping about?).

I suggest you tin plate the piston skirt with a "lead-wipe" of Tin based solder.
I.E. flux the piston, tin it with solder, and while the solder is HOT and liquid, wipe it quickly with a dry leather cloth (Chamois leather is OK). WEAR GLOVES so you do not burn your hands! SKIN BURNS AND HURTS when touching metal as hot as molten solder. But this is how Plumbers made their soldered joints before factory pre-soldered fittings were available.
Then check there are no blobs or high spots of tin solder on the piston, and mic it to see if it needs linishing to size, around 0.001 to 0.0015" smaller than the bore - if it is a 1" diameter piston. (Linishing can be simply done by someone skilled and careful, using a file, but only as a rigid flat holder for a very fine emery paper to take off the tiniest amount of solder to reduce the diameter by a fraction of 0.001", while turning the piston at only 100~200rpm or so in the lathe).
I expect this tinning technique to increase the diameter of the piston by something like 0.0005" either side = 0.001" diameter.
The tin-solder in application in the engine is good for maybe 130 deg C - and I doubt you'll be doing enough work with the engine to need over 30psi steam!! (3 ~5 psi more like if just idling!). The tin is also a good bearing surface to slide in the bore.
Or you can make a new piston... with 0.001" clearance.
Of course, if it is a 2" bore engine then the clearance is about right...
But be cautious, measuring fractions of 0.001" requires very good measuring equipment and technique... Often not available to the Home machinist! (re: controlled temperature, slip gauges for calibration, etc.).
Take 10 measurements of the piston diameter, putting everything (piston, measuring tools) on the bench and turn around every time. Then do some statistics to see if you can measure the same thing repeatably. And I don't mean "can you repeatably turn the knob on the micrometer to the same number every time". I mean will the micrometer give you the same reading every time you pick-up it and the workpiece, and measure the part? Some micrometers have a vernier calibration around the barrel to achieve 0.0001" increments, but I am not that repeatable! And how repeatable are you at measuring the bore? Usually dial gauges to measure bores need to be set to the micrometer.. Set the micrometer to the piston diameter +0.001". Insert the bore gauge to the micrometer and set its DTI at zero. Compare this to the bore and see what size it really is... I was doing this at 12 years old, but all my work was double checked until I was 14 or so and was allowed to re=bore and hone engine blocks for cars on my own...
Give me a thumbs up if that makes sense to you? - Or I can accept a thumbs-down and corrective criticism from anyone who has more expertise than I. - Let's get it right.
K2

Sorry, the word came from Latin not Greek, don't be a geek.