Three Cylinder Radial Engine

[sbwhart]

Well this post is going to be a tail of Triumph over near Disaster.

Made a start on the crank shaft, drawing calls for a solid one piece crank shafts, all crank shafts I've made to date have been fabrication, but this being a one throw crank shaft I thought i'd make it in one as the drawing.

Ok first part using a 3" long bit of 32mm dia free cutting mild steel turn the main journal 3/8" dia.



Turn it round in the chuck and drill a 2.5 mm hole 2" deep for the oil way.

Centre drill then a jobber 2.75 mm then finish off with a 2.5 mm long series drill, drilling part way with an over size drill gives a bit of clearance for the swarf reducing the chances of it clogging and breaking, also keep clearing the drill back:- job done.



OK turning the offset for the crank.

Plan A :-

Mark off set with a small centre pop then with a pointed bar in the centre pop clock the bar up turn dia.

Marking out

Mark centre line and set centre line vertical


Touch on top of bar



Bit of maths

Mark position of off set



Centre pop and her we have it in four jaw ready to be set up.



At this point tried getting it roughly set on the bench, and realized that with one jaw set over the next two jaws wouldn't close down, the diameter was too small.

Ok plan B. Make a bush with a 3/8 bore clamp the crank shaft with a grub screw positioned in a none important place (grub screw would mark the shaft) then I remembered that if you put a packing piece between the job and the chuck jaw you could get the off set, so decided thats what I would do.

Her we have the bush on the shaft with the packing piece.



And job part turned



OK spotted the deliberate mistake.

 

I'm using a three jaw, the geometry is all changed I used a 1/4" packing piece to get a 1/4" throw I should have used a bit of trig and worked out a thicker bit of packing or used a self centering four jaw.

A quick check and phew I still had enough meat left to get the job done.

Plan C:- well back to plan A really but using the sleeve to give more of a diameter to grip on.

Still had the off set marked with a centre pop on the bar end.

So her we are clocking it up



And part cut:-  interesting shape with the near mis not quite cleaned away.



1/4 dia turned and drilling the oil way.



Turned crank



And in the housing



Well that came out all right in the end I'm sure glad I did a quick check as to how the throw was coming out when I did.

Cheers

Stew

[Stilldrillin]

Stew,

Once again, you can say you`ve had a good day.   

All`s well, that ends well........ 

David D

[andyf]

Stew, you've already made a nice job of it, but if you ever do need to offset something in a 3-jaw, the formula is
Offset = 2/3 shim thickness. So, to get a 10mm offset you need a 15mm shim.

I didn't work it out for myself  . It's explained towards the bottom of this page: http://homemetalshopclub.org/news/aug03/aug03.html

Andy

[sbwhart]

Thanks Andy

Thats filed away in my little black book.

Great link by the way.

Have fun

Stew

[NickG]

Stew,

Well done with that, you've done a great job there.

I thought about doing the same for the offset in the 3 jaw. I would have used 1/4" packing for 1/4" throw too - will have to look at Andy's link to find out why it's not!

I hate doing those, just hate the interupted cut - what size cuts did you take, did it take long? Maybe I had the speed too low.

I did it with a split bush on my rocking engine as remember the hassle I had using the 4 jaw on my stirling. But I drilled the offset hole in the bush in the milling machine and it must have wondered off because my crank disc wasn't uniform thickness.

Was the main dia. of the crankdisc part too thin to grip on in the 4 jaw?

Nick

[sbwhart]

Hi Nick

For plan A I used a 5/8" square HSS tool with a speed of about 350 rpm feed about 0.01mm and a cut of 0.5mm:- for plan C I used a tpmr TC tool same speed and feed but a cut of 0.75 mm, when doing jobs like that I just listen to the complaints from the machine when it looks and sounds happy I keep to that recipe, ( treat it like a woman  ) I don't try and rush things, to turn the offset took me about 3 hrs with all the messing about.

Cheers

Stew

[NickG]

Cheers Stew, will bear this in mind next time!

[sbwhart]

Managed to steel a bit of time in the shop this morning and finish off the crank.

Blued the web up and set it up in the spin indexer, then by using my height gauge touching on the web then with a bit of calculation set the crank up so it was on centre line.



Then using the indexer and the height gauge marked out the web.



First bit of machining indexer rotated to bring the crank vertical and drill the oil way.



Then with a nice big milling cutter hack out the web shape.



Then mill the flats to drive the valve crank. By rotating the indexer 180 the flats came out nice and symetrical on the crank.



A quick debur  and thats it done just need to plug the oil ways up.



Cheers

Stew

[NickG]

Nice crank there Stew. That spin indexer has come in handy. I was showing one of the apprentices here some of your indexer pics a couple of days ago to explain some of his college homework!

Nick

[sbwhart]

Nick

I'm pleased that my pics were used to help a young chap with his education.

Got the fly wheel completed, the drawing calls for a cast iron flywheel but I'd got some suitable brass and I also like making composite brass ally fly wheels.

So first job make the hub I'd got a bit of ally the correct diameter but it was a bit on the thin side to chuck and part off, so I put a hole down the middle of it and held it on a loose mandrel to turn up the OD.



Then stuck it into the middle of this chunk of brass, I found quite a few bits like this down the scrap yard.



The fly wheel is held on the crank using a split tapered collet. so to make the collet, swing the compound over to 5 deg (10deg inclusive) and turn the taper, then put a 3/8" dia drill down the middle, and part off.



Then don't move the compound, keep it set.

Chuck up the fly wheel, flip the boring bar upside down, and working at the back, bore the taper in the hub, because nothings bin moved the tapers will match perfectly.



Skim up the OD of the fly wheel part off and face the other end.



Split the tapered collet and her are all the bits for the fly wheel completed.



This is how it looks





Thats all the outside bits of the engine done just the innerds to do now.


I guess thats all until after Christmas

So I'd like to wish you all and your families a very merry Christmas.

Have fun

Stew





 

[Stilldrillin]

Stew,

That engine`s looks improve almost every time I log on! 

Here`s wishing a Very Merry Christmas, to you & yours. 

David D

[Divided he ad]

That look great Stew      


Gonna be good to see it running 



Hoping you have a great Xmas season....

I'm just planning to spend time in the 'shop! I've a whole week and a bit off...... Got to try to do something!




Take it easy,



Ralph 

[Bernd]

Looking real good Stew.

I like your split collar method of attaching the flywheel. But the upside down boring bar makes my stomach a bit queezy. 

And a Merry Christmas to your too.

Hey Ralph, you ever going to finish your Aeolipile? (sp?)  Ya, I know 

Bernd

[NickG]

That's excellent Stew. I like that method of fastening a flywheel. in fact I was going to try it on my engine last night with a lighter flywheel. Engine is looking great.

Merry Christmas to all.

Nick

[sbwhart]

Happy new year Chaps

I bet you thought I'd given up on this. Spent new year St Ives a Cornish fishing village/town, made a complete fool of myself by joining in the fancy dress party that the town holds, got a little bit tipsy dressed as a red indian (must have been the fire water).

Any way on with the build:- con rods.

First job draw the rods out in cad and dimension the key features from the centre line of the big end bearing, then cut some plate to size, for the rods important to get all the bits the same size as it will help help in doing all three with the same set up.



Then set up in the mill bringing the vice stop into play then drill big end zero the DRO in X and Y and then drill other holes, repeat, repeat.

Her we have them all drilled.



Put a couple of same size rods through the web holes sit them on to a couple of parallels, tighten up the vice remove rods and parallels.
and chew out the meat.



Fit the big ends with 1/4" phosphor bronze bushes, the little ends are also drilled 1/4" (that I will bush later) and make a 1/4" mandrel, one mandrel will do both ends.

Then fix on mandrel and thin the webs.



Flip over and locate on the other end and thin the other side.




Then with the mandrel held in a collet on the rotary table round the ends off.





There we are done they just need a tickle with a file to tidy up.



The centre con rod is at the back in this pic with the two off set rods in the fore ground.





Have fun

Stew

[Stilldrillin]

Nicely done and shown Stew...... As usual! 

And a Happy New Year to you and yours! 

David D

[NickG]

Wow, 

You did those con rods so well I've just thought of a genius nick name for you - Rod Stewart!    never mind!

Seriously, they are really impressive, everything seems churned from the solid on this! Looking good.

Nick

[Powder Keg]

Nice job on the rods Stewart

[sbwhart]

Made a start on the pistons over the last couple of days. The first thing I did was to hone the cylinders sp that I would have a final size to work with, I used a flexie hone with plenty of oil, I didn't go over board with the honing just a quick lick up and down for about 10 seconds, but it was enough to produce a nice smooth bore.



Then used this new toy to give the cylinders a good clean, its a lidle ultrasonic cleaner on offer for £20:- Great for cleaning glasses and false teeth, wanted to try it out on Mother in-laws teeth, but the miserable old bugger wouldn't let me.



Then I carefully measure the bores they were all within 0.02 mm and kept a not with each one of their size.



The turned down a chunk a window sash weight and drilled and bored the ID.



Then I wanted to try out my home made tool post grinder to get a nice finish on the OD of the cylinder, it took me a good bit of time and a lot of 13 amp fuzes (don't ask  ) to wire up the new toggle switch I'd bought for it.

But it worked a treat got a nice finish on the cast iron and a nice fit.



This is two ground up and just sitting nicely in the bore, the third is still on the bar waiting to be parted off:- thats a job for another day



Have fun

Stew

[NickG]

Stew,

Looking great, I bet with that flexi hone and grinder you have got an amazing fit there. Very nice. That ultrasonic cleaner is a bit posh too, did it work well?

Nick

[sbwhart]

Thanks Nick

The ultrasonic cleaner worked great, you can use plain tap water or add a few drops of washing up liquid for real dirty bits. They can be too good caused a lot of problems with fuzes the parts were too clean to function, ended up adding a small amount of oil to the liquid to put a bit of slip back in the system.

Have fun

Stew

[Rob.Wilson]

Very nice Stew    looking great 

Regards Rob

[raynerd]

Stew, do you think the ultrasonic cleaner would be good enough to clean up old watch and clock movement parts? I know you can pay hundreds for them and appreciate they probably wouldn`t compete with those but do you think they would do something or at least worth the £20 you paid for that sort of thing?

Chris

[sbwhart]

Hi Chris

I think it would be OK for watch and clock parts, although I wouldn't recommend using it on an expensive watch, it comes supplied with a basket that keeps the movement clear of the liquid whilst you clean the steel bracelet in fact I used it to clean the bracelet of my watch, it did a good job. I got it from Lidles who currently have them on offer, so far I'm happy with it.

Hope this helps

Stew

[Powder Keg]

Looking good Stew!!