First mini lathe project, oscillating steam engine.

[doubleboost]

Hi
Ross
You need to remove the tube.
Use some packing pieces to protect the job (i use bits of aluminium plate.
If you have a clock gauge it will make set up much easier.
What i do is put a spare lathe centre in between the punch mark and the tail stock centre.
A clock gauge is placed on the spare centre near the chuck .as the job is rotated (by hand)the spare centre will wobble about the chuck is adjusted until it remains stationary.
Sounds complicated but is really easy to do , you can get it to run dead true by this method.
I have been looking for a picture of the set up
If no one posts a picture for you i will do a video (worth a thousand words)
John

[doubleboost]

Yhis shows how to do it
If it is good enough for Rob it must be good

John

[Ross]

Hi
Ross
You need to remove the tube.
Use some packing pieces to protect the job (i use bits of aluminium plate.
If you have a clock gauge it will make set up much easier.
What i do is put a spare lathe centre in between the punch mark and the tail stock centre.
A clock gauge is placed on the spare centre near the chuck .as the job is rotated (by hand)the spare centre will wobble about the chuck is adjusted until it remains stationary.
Sounds complicated but is really easy to do , you can get it to run dead true by this method.
I have been looking for a picture of the set up
If no one posts a picture for you i will do a video (worth a thousand words)
John

That's a great tip. Thanks for the video link too, I'll give it a go later.

[Ross]

Hi everyone,

I set up the square block in the lathe, it took a while to get it perfect but it was satisfying once I'd got it right. 

First I centre drilled, then I started with a small drill bit and worked my way up. 







I drill the hole to 11mm. Though I'm not sure about the best way to finish it. The final diameter for the bore is 12.5mm do I ream the bore or can I use a boring bar to achieve a good finish? 

That all for now. 

[Divided he ad]

Hi Ross... A few links that may help you get it finished straight?

Boring does work but often leaves a surface in need of lapping.

Else you could have a go at D bits and then a little amount of lapping may be required?




If you have the need to smooth things out a little afterwards?
http://madmodder.net/index.php?topic=591.0   




  If you have the means to make them?
http://madmodder.net/index.php?topic=2312.msg24257#msg24257 

http://madmodder.net/index.php?topic=1334.msg11778#msg11778
 



Hope that helps in some way? Good luck 







Ralph.

[MadNick]

Yhis shows how to do it
If it is good enough for Rob it must be good

John

Good link, I've always wondered how to do this.

Nick

[Ross]

After speaking to still drilling on the phone last night, I decided that I'd try and use a boring bar to achieve the finish, I felt D-bits would be a bit of a pain to make for a beginner.

I made a couple of passes, the tool rubbed alot so I re ground it and it seemed to work better, though some 'lapping' was required.

After a while I think I'm happy with the finish, there is no nasty lines just a nice smooth finish all the way down.

Here is a picture, but is hard to photograph as the lighting is no good in the shed.


The next step is to put a recess on the end of the hole. I drilled right through the cylinder so I'll make a cap that is fanged to fit the recess and solder it in. But what is the best way to effectively cut the recess?with a normal cutting tool making small cuts working out from the hole?

[Divided he ad]

But what is the best way to effectively cut the recess?with a normal cutting tool making small cuts working out from the hole?

Personally I'd use the boring bar.

Assuming that your recess is going to be very slight, 1mm ish deep and not much wider than the bore itself?
Then you can as you said. go into the hole (not touching metal ) and then cut out as far as you want to.

You could also set the bar at the desired width and plunge cut the recess (you may want to experiment with this method first... Know your machines/tools capability and all that!)


If it's deeper and too much for one cut without chattering then I'd make multiple small roughing cuts and then a final one to finish it off neatly.


We probably have different ways of making stuff (We all do I suppose) but my way would be make the recess and then make the cap to fit it.
That way if I made a mistake, say wider or deeper recess than I originally wanted. I make the cap fit my mistake and it's not a mistake any more..... Well, not for others to know anywho 



As said... Personal method. Plenty of other ways of flaying innocent kittens! 




Ralph.

[Ross]

I Put the recess on the end of the cylinder, and took it out of the chuck. thanks for the tips!

Picture:





In heinsight I should've drilled the hole for the cylinder port before drilling the bore. It'll leave a burr when I do, but I've made a little makeshift honing tool which should clean it all up a treat hopefully. 

[DaveH]

Ross,

Coming along nicely - well done

 
DaveH

[doubleboost]

Hi
Ross
Well done 
Every time you do something you learn a little bit more
John

[Dean W]

Hi
Ross
 

Don't quite understand this.  He's put pics in almost every post!

Doing great, Ross!  Keep at it.

[arnoldb]

 Hi Ross

   Your doing a fine job; just take it a bit at the time and you'll soon have a runner 

In heinsight I should've drilled the hole for the cylinder port before drilling the bore. It'll leave a burr when I do, but I've made a little makeshift honing tool which should clean it all up a treat hopefully.

Kudos to you for thinking through things like that  - you'll find thinking about things a bit on future projects one of the best tools in your shop, but it does come with a bit of "learning the hard way" 
The burrs are a problem either way; if you did the port first, it's very likely that the boring operation on the cylinder would leave a burr in the port - slightly blocking it.  That then has to be cleaned up by running a drill through, and in my limited experience will bend over a bit of the burr into the cylinder again - requiring a bit of a lap or run-trough with a reamer again.
Either way in my experience, you need to fine-finish the bore of the cylinder as a last operation. 
Don't worry about this too much for your first engine though  - once the bug has bitten you and you build more engines, you'll naturally start thinking about these kinds of issues.  The main thing is that you take every bit that you learn and try and apply that later - sometimes its frustrating, and at other exhilarating - but either way its a load of fun 

 , Arnold

[doubleboost]

Hi
Ross
 

Don't quite understand this.  He's put pics in almost every post!

Doing great, Ross!  Keep at it.

Sorry i clicked the wrong icon (be the wine)
Pictures are great by the way
John

[Ross]

Just another update,

I drilled the port hole through on the cylinder. 

Somehow it is out and to the left by 0.7mm  so I opened the hole out a little with a centre drill, and worst case I can move the port holes on the plate that the cylinder will sit on across 0.7mm.  I double checked the measurements by touching on with the drill first and all seemed well, but these things happen I suppose!






I de-blurred the bore of the cylinder with my little homemade honing/lapping tool on the drill it worked brilliantly, so I'm happy with the finish inside the bore. 





I'll try and find the time to machine the cap for the end of the cylinder this week, I just want to get this part done before no more mistakes happen!!

[Divided he ad]

and worst case I can move the port holes on the plate that the cylinder will sit on across 0.7mm.

Is right! 


I've done a lot of that "slightly out" type drilling before, and for that matter a few cases of slightly out milling and turning too.... Quite a few more regularly than I should probably admit to    Anyway....
Usually I take a step back, tell myself off a little, get over it and figure out whether I can continue to use it in a slightly modified fashion?
Same as you have     





Other than the little misfire it all looks to be going to plan 

Keep at it Ross, you'll have a loverly little wobbler in no time. (calling Mr Howard, time for your tag line  )







Ralph.

[DaveH]

Ross,

Looking good   

 
DaveH

[Ross]

I made the end cap for the cylinder today, It was fiddly to make but I got there.

First I turned the diameter of the bore,



Then I  turned the diameter of the part that will fit into the recess,

 

I cut the material in half and worked backwards facing the length. 



I purposely left and overlap on the length of the end cap I was going to make it flush but I decided against it. I put a taper on the cap too.

Here is the finished article:



And it fitted on the cylinder.



I'll have a go at soldering it at the weekend, enough work for one day!

 

[DaveH]

Good job Ross 

Fiddly is good,    once one can do fiddly things, then you will be able to do anything 

It is coming along nicely 
 
DaveH

[Stilldrillin]

Ross.
This hobby is all gubbinses and widgets...... And that widget looks right at home, mated to the gubbins you made earlier! 

Well done! 

David D

[Ross]

I soldered the cap on today, 




And out of curiously I polished it too!




Now I've neely finished the cylinder, I've just got to drill and tap the hole for then trunion pin.  It needs to be M3, I got a set of taps for Christmas, but I wouldn't trust a tap as small  as that from the set! 

So I need to buy a high quality tap and drill, I've found a 3mm tap, it's a reduced to £3 would it be okay just to get a plug tap? 

(15th down)

http://www.tap-die.com/contents/en-uk/d140_Metric_taps.html

[DaveH]

Ross,

So I need to buy a high quality tap and drill, I've found a 3mm tap, it's a reduced to £3 would it be okay just to get a plug tap?
(15th down)
http://www.tap-die.com/contents/en-uk/d140_Metric_taps.html

It can be difficult to start the tap, especially if you don't have a taping stand.
Also one is more likely to break a plug tap(because of the full cutting force) without using a taper tap first.

 
DaveH

[andyf]

In brass, I'd use a cheap (Aldi's) tapered tap first, to give a decent plug/bottoming tap (with its point, if it has one, ground away) an easy start.

Andy

[Ross]

Today I machined the crank to the correct diameter, I'm waiting for a tapping drill, to arrive for the cylinder. 

[Ross]

Hi everyone, 

Today I got around to drilling and tapping the cylinder. I brought a proper M4 HSS tap as the Chinese taps I have look like they are made out of plastic and I just can't trust them! 




I also did a bit more to the crank and turned part of it down so that the hole for the M3  grub screw can be drilled. Tommorow I'll set up up offset in the lathe and drill the hole for the crankpin too.