"A Beginners Engine" From Model Engineer.

[sbwhart]

Looking good Alex.

NickG is building his from the other end and he came across a couple of mistakes on the drawings so her they are:-

Part MP39 crank shaft spacer the hole is 6mm diameter

Part MP30 crank shaft better to make it 100mm long

Part MP33 Main Bearing it should be 10mm wide

I've added V2 of the drawings
 
Cheers

Stew

[NickG]

Looks great. I may use the same method fir the cyl / caps unless i get my rotary table up and running and am feeling confident!

[ParCan]

Hi Nick
I have a rotary table but no method of fixing a chuck to it.
My Table is also rather cheap n nasty with heaps of lash in it.

I centred the Cylinder with the end cap glued in place.
Chuck up a bit of 4mm rod (that fits in the gland hole) Use that to centre it.
There is a vertical V in my vice. Used that to locate the cylinder in the vice for when I turned it over. 

[NickG]

Mine is a 6" vertex and feels great with little backlash but never used it, the clamps look good too, 1 either side of the table. I had no way of putting chuck on it either but have just bought an ML7 so have ordered a 2mt to myford thread adaptor which would let me leave the bits in the chuck and transfer to the table. Should be an interesting experience if nothing else!

Ah good idea, i've tried something similar in the past but don't have the luxury of the vee in the vice.

I also bought stevensons er32 collet blocks sq and hex for this sort of thing but then realised my collet set is er25 - doh!

[ParCan]

Hi again.

Another productive day.
Crankshaft, Con Rod and Crosshead completed.

I Started 3 Crank Webs just in case. All 3 came out pretty much perfic.
Crankshaft was all rather loose so I decided to Pin it. Broke a drill in 1 web so that became the spare by default.
I decided to use screws as the pins. Easy to get out. Final will have Grub Screws in it I hope.

The Con Rod I decided to make as 1 bit.
I didn't have any steel the correct width which would make attaching the Big End bearing a bit of a nightmare.
I also don't have any 1/4 square Brass. (I plan to mill the cross head slides from what I have)

I did the crosshead on the Mill. It's a tiny bit shorter than the drawing.
Also note. The M3 Thread for the Piston Rod should be M4.

Big and Small end bearings are Oilite Bushings I had in stock.

 

[DavidA]

ParCan,

It's a bit late now, but I missed the thread.

Sash weights are often chilled.  I once bought a sash weight for a job and had to give up on it as it was too hard.

Sorry for not noticing earlier.

Dave.

[krv3000]

Looking good Alex.

[ParCan]

Eccentrics today have not gone well.

I decided to make a steel inner and Brass strap.
The only suitable steel I had started out at 2" dia. A few passes of a roughing tool sorted that ...

I turned the 20 mm X6 deep shoulder.
Out came the Parting tool which really struggled in the std tool post.
Decided to try the rear parting post for the first time and I have to say it worked a treat on the 1st bit.

And I parted it off all the way.

Moved 1 jaw of the 4 jaw 3.5 mm measured with a drill.
Pushed the work across, Double checked the 3.5 mm offset and centre drilled it.
Then I looked at the first part which was missing said 8mm hole 

Turned the 2nd bit and then tried to part that off.
Tool post was hitting the chuck so took that off.
Then the jaws were hitting the Saddle (by quite a margin.)
Had to move the tool post as far as I dare off the side off the cross slide.

Carried on and hacked my way around the missing hole issue....
I superglued the 2 bits together back to back. Centred them on the mill. Centre drilled the 2nd part, then reamed them both to 8mm.

As I have some tiny M2.5 grub screws I decided to grub screw both bits.
The Eccentric strap was a simple turning and boring job and has come out really nicely.

 

[sbwhart]

When parting off Alex don't be afraid to resort to the Mk1 parting tool:--- the good old hacksaw:- we all resort to it if we were honest 

Looking good I recon at this rate we will be seeing a video of the running engine soon 

Stew

[NickG]

Yeah good progress there alex, the con rod and eccentric look good.
I had trouble with the crank too i may have to re-make. The trouble was i had to turn down to 8mm and the 8mm end mill gave me a good fit on the bearings didnt on the webs for some reason! Had i realised i had a 5/16" reamer i would have made it that size instead. i might use grub screws rather than pins if i make another But if i can get away with fixing the existing one i will do that as it took ages!

[ParCan]

Did all the tiny bits after lunch.
There is something strangely sadistic about making 1/4" square steel blocks and putting a hole in em !
All the Piston valve connection bits made.
Crosshead slides made.
Valve rod guide made.

The Boss will probably stop work over the weekend.

I now have the 4 Pillars to make, the 2  Bearing stands and the Base. I think that's about it.

The whole thing feels free as it stands. We will see what happens when I start to bolt it down.   

[ParCan]

I had trouble with the crank too i may have to re-make. The trouble was i had to turn down to 8mm and the 8mm end mill gave me a good fit on the bearings didnt on the webs for some reason!

I have 8mm Stainless rod and an 8mm reamer. Also 6 mm Silver Steel crank pin and a 6mm reamer.
Why they came out so loose I have no idea.
What I have here and now Is imperfect as far as I'm concerned, but it should work.

[sbwhart]

I had trouble with the crank too i may have to re-make. The trouble was i had to turn down to 8mm and the 8mm end mill gave me a good fit on the bearings didnt on the webs for some reason!

I have 8mm Stainless rod and an 8mm reamer. Also 6 mm Silver Steel crank pin and a 6mm reamer.
Why they came out so loose I have no idea.
What I have here and now Is imperfect as far as I'm concerned, but it should work.

Are you using machine reamers or hand reamers: Machine remers are parallel along their length Hand reamers are tapered at the start and usually have a square on the end for a tap wrench.

If you put them through under power held in the tail stop in a chuck the chances are they cut over size due to misalignment best to drill out under size to within say .3mm ish then put the reamer through by had so that it cuts true, if using a machine reamer they are best put through with a floating holder or push it through on a carrier with a running centre, like this.



that way it will cut true size.

Stew

[ParCan]

I have seen this done before and used this method for the Valve Body which I did on the lathe..

I did the crank webs on the mill.
8mm ER 25 Colette.
Used an 8mm dia Centre drill to locate.
Then through with a 7.5mm a few times.
Then through at around 100 rpm with the Machine reamer.

Same process but 6mm all round for the other end.

I thought I'd at least get them to be a tight fit...
Reality is they are a sliding fit at best.

[NickG]

They should be a nice sliding fit when reamed which is about ideal for loctite. My 1/4" crankpin was like that.

[ParCan]

BOTHER BOTHER BOTHER ( or something similar)

The M3 Holes for the cylinder caps were rather to shallow. I went back through with a 1st and 2nd tap as far as I dare.
The 3rd tap was getting tight so backed it out. Was about a mm to shallow still.

I guess you know where this is going......

I got to where I stopped last time, 1/4 on 1/2 back. 1/4 on 1/2 back 1/4 on 1/4 back and that was it.
After a good careful wiggle On and off the tap was trapped.
More fluid but alas it was stuck on the back cut.

Anyway made the Crosshead posts this am.
They are currently all over length at the moment.
I can take the tops off on the mill to make em all the same height.
Whats the best way to do these on the lathe ?

[NickG]

I just measured how much needed taking off each one with a mic and then took a final facing cut in lathe.

[ParCan]

Managed to get a bit of workshop time over the weekend.

Crankshaft Bearing holders are done. Not happy with these so will probably re make.
Crankshaft bearings are done.
Pillars are complete and all the same height. Broke yet another Tap. I'm really not doing well with these small threads and it's always on the Back cut.
The 16mm Steel Bar I had was a freebie and does not cut or machine well. It's not even round by about a mm. Really cheap n nasty no doubt.

If there is 1 lesson I have learned from this project is cheap nasty metals do not help you. They are not nice to machine, Don't give you a nice cut, the finish is poor and it's not consistent to machine.
The Sash Weights are Glass hard in places, Machines wonderfully in other areas. Drilling the ports the drill would go in clean and nicely for a few mm then start to snag and snatch, I'd get through the hard bit and it'd drill fine again.

I still have not got the tap out of the Cylinder. Going to try and heat it tomorrow. It'll be double or quits.

temporary Base is made from 1/8" Perspex and drilled. I plan to use this as a template for the real base.

I have started the initial assembly. Can't complete without M2 nuts, I really do hope these turn up on Monday.
With luck I will be making a video on Tuesday...

[NickG]

Alex, I learnt that a while back and started buying in what metal I needed - it is much easier to machine, get better results and can save any heartache! I've not got bits left over that I want to use up but have found myself wasting time brining stuff down to size as I've said. Next project I will buy what I need for the price of it, I am quite spoilt by having M-Machine metals only 7 or 8 miles away though.

[ParCan]

Despite heating the Cylinder and really carefully trying to get the tap out, it's broken inside.

Oh well. win some and lose some....

With the Inlet / Exhaust on the wrong sides of the valve and 2 broken taps in the cylinder I may well remake them.

The rest is now together and runs fairly smoothly.

[sbwhart]

If you have all the bits made my as well give it a try just for fun before you remake.
As youre breaking taps try using a slightly larger  tapping drill you will still get a good thread

[NickG]

 I always go 1/2 turn forward 1/2 back too and usually withdraw completely at least once to clear swarf. Still get the odd breakage though. Are they broken on cover bolts or for the valve chest? Could turn cover a bit and re-drill if it's there.

[ParCan]

Hi Nick

I have an M2 in the Valve Chest. That was my fault and totally accept that. Simply to ham fisted on the Back turn.

I have an M3 in the Cover End cover.
This one I don't get. I was gentle and using a Jig to hold everything square.
I had Cutting Fluid and knowing that this iron is not the best thing to thread was using fair force and taking things slowly.
The tap had been in and out probably twice to clear dust and swarf.

Anyway - everything is together here and now. The 4 Crosshead pillars are slightly to tall causing the Piston rod to bind. That's easy enough to sort.
The eccentric was fun to get setup but the throw is now correct. Just need to sort the timing. 

As the drawing was not quite correct I have to sort out how I mount the flywheel. I'll prolly put a pin through the Shaft.
Plan B would be to Knurl the shaft and some Stud lock maybe.

That should all be doable tomorrow am, then I'll see if it's a runner.
 

[ParCan]

After a fun week in the workshop I have a completed engine.

Gasket gunk applied to the end caps and valve.
Oil in the air pipe

Time to see if it runs I suppose....

and

I'm rather pleased with the results....

[NickG]

Great result! Well done