Enlarged Rocking Engine Build

[NickG]

Never thought of that! I have forgotten how useful the 4 jaw can be since I got milling machine - and my 4 jaw is too big!

[Ross]

Hi everyone,

I got quite a bit done today, I followed the advice given and took the aluminium plate down to size and it s square and fat!



Then I marked out the holes on the plate.



And then drilled.





And then I marked out and drilled the holes in the bottom ad tapped M4





And then I rubbed the faces and sides down with sandpaper to remove the marks etc..



And loctitited the bearings in the holes flat.




And while that was drying I turned and finished the crank shaft diameter.




All in a days work!


Ross

[Stilldrillin]

Nicely done Ross! 

That toolpost looks right at home there........... 

David D

[Bezalel]

Hi everyone,

snip > the aluminium plate down to size and it s square and fat!  <  Snip

Ross

oops!


you're supposed to feed the tool into it, not cottage cheese   

But nicely done !


Bez

[Ross]

Hi everyone,

snip > the aluminium plate down to size and it s square and fat!  <  Snip

Ross

oops!


you're supposed to feed the tool into it, not cottage cheese   

But nicely done !


Bez

I am a incredibly in accuate typer! And sometimes auto correct dosent pick up the pieces. 

[arnoldb]

All in a days work!

A good day's work at that Ross - good going

Kind regards, Arnold

[NickG]

Yeah nicely done Ross - still kicking myself at not thinking to do it in the 4-jaw!

[V 45]

Looks like it's going well for for you Ross. I really like the 4 jaw concept !!
Well done...
  Dave

[Ross]

Hi everyone,

I've taken another few weeks off on this but I've been busy doing a couple of bits and pieces to my lathe, I've fitted a new guard and a lamp which I made, the light makes a world of difference.



To test it out I had to turn some sleeves for the I/D crank wheels due to me stupidly ordering 5mm bore bearings and drilling the crank wheels to 6mm

I turned he O/D to suit the bore of the wheels and then drilled the bore 5mm and parted off two parts. there isn't much material in it and I thought it was going to all end in tears, but I'm pleased with the result. Just a couple of holes to drill for the grub screws to slot through.

[Stilldrillin]

Hi Ross.
One good thing about owning a lathe....... You can put right the muck ups, you've made with your lathe...... 

I like your chuck guard. It stops a spotty stripe appearing, downwards from your left shoulder. 
I made mine from a piece of alloy chequer plate. Formed over a 6" dia log.

Must get meself one of those lamps, to shine into bores........

David D

[Ross]

Hi everyone,

Today I started roughing out the support posts that will go between the engine frame and the base.

I have to make 5 of these so I changed the design to keep it simple and so there less margin for error.

Here is a rough drawing, I left the diameters off as I didn't have the measurements on hand.  I'm trying to use imperial measurements more and more, but all the threads are still in metric!



Firstly I parted each post off and roughed out the thread length at the top. This varied slightly per part so I could keep the length of the body the same.







I left the main body of the posts .300" long for ease of clamping.

I drilled the 4.2 mm holes in the bottom of each post for the M5 Thread.



And then I started to turn the O/d of the thread length I marked out previously to 4mm and threaded.
From here, it all goes downhill.

I decided to face the first off to length - .500" and it was all going well as it should. I turned the top half O/D of the part down to 6.25mm.

I went in for the finishing cut of this O/D and was just winding out at the back face when I accidentally knocked the feed on. The part partly sheared out of the jaws and the cutting tip of the tool snapped off. Sadly this mangled the part and the tool beyond repair.





I continued on with the next part and did the above, I was using a new tool and I was having major problems with the clearances as it was rubbing while I was facing it to length. It works fine when cutting the O/D's though. The tool I'd broke worked I'd never had a problem with the grinding clearances but I really can't get the hang of grinding these bigger tools.



I've left it for now as I didn't want to go scrapping all the rest off because of badly ground tools. Maybe a interchangeable tip tool would be a good Christmas present?! But I'll see what you guys think. 

Ross

[Ross]

Hi Ross.


Must get meself one of those lamps, to shine into bores........

David D

The lamps are very cheap, I've noticed that B&Q do a flexible clip lamp for ?8 That might be worth a look!

[Stilldrillin]

Hi Ross.


Must get meself one of those lamps, to shine into bores........

David D

The lamps are very cheap, I've noticed that B&Q do a flexible clip lamp for ?8 That might be worth a look!

Wilkinson's..... Looks just like yours, round base ?4.99. 

But you don't get a bulb! 

David D

[NickG]

Ross,

Shame about the little mishap. Don't worry, similar things happen to us all - well me anyway!



Are those tungsten carbide tipped tools you are using? I get better results using high speed steel tools. For aluminium, as it is quite soft you need a large top rake angle - up to 40 degrees but you'll probably find anything from 20 works ok.

You then need a small angle coming away from the workpiece from every other direction. Make these fairly small to keep the rigidity. Nice sharp point with a tiny rad on the end, I usually don't try to grind that on, just make sure there are no burrs with an oil stone. If it feels like it's going blunt, a few rubs with an oil stone will do.

This is a pic I showed for a tool that turns a radius in a flywheel (steel so about 20 degree top rake), the idea is the same but you won't need the curved side to clear the recess as you're not making one!:

[NickG]

Another observation if I may - there are obviously lots of different ways of doing things, but the way I'd do this would be to leave the material on the parent stock for as long as possible.

So rather than parting off your 4 lengths, I'd face the end of the bar, turn the intermediate diameter to the right distance from the end of bar, turn the thread diameter to the right distance from the end of the bar, put the thread on, part off to correct length. Do this for all 4, then put them back in the chuck the other way around to drill and tap one by one.