Tiny Vertical Based On G. Britnell's Design

[sbwhart]

I'm get very very close to steaming my loco (honest) its been a bit of the trial and may still jump up and bite me, but I've been getting very itchy to design and build an engine.

This one is not all my design I've based it on Georges' design that you can follow her  http://www.modelenginemaker.com/index.php?topic=570.0 but as I'm on the metric side of the pond I've been converting Georges' drawing to metric friendly sizes, I've also designed it with a piston valve instead of the slide valve George used as I hope that will be easier to make:- we will have to see on that one.

I still have some detail work to do on the drawing and to fill in the dimensions plus I still have that loco to try in steam and I have a few family commitments over the next couple of weeks.

In the mean time I've ordered some kit that may help me make it and some tiny M1 taps, dies, nut, and bolts.

So that I can jump in and start cutting metal in a couple of weeks

In the mean time just to give you some ideas of what the jobs about I've attached the assembly drawing.

Stew

[Jo]

 

Stew, I hope you have a UPT to help with tapping those tiny holes.

Jo

[sbwhart]

Hi Jo

What is a UPT ?

Universal Power Tapping ?.

Stew

[Jo]

GHT's Universal Pillar Tool, Just the beasty for using to tap very small holes without breaking taps

http://www.modelenginemaker.com/index.php?topic=2911.msg50182#msg50182

http://www.modelenginemaker.com/index.php?topic=2004.msg30932#msg30932

Jo

[Tennessee Whiskey]

I like tapping them as soon as I drill them. Same hole, same setting, just a different tool. 

Big E

[Dave Otto]

That's what I do also Eric.

Put the tap in the baby Albrecht Chuck, loosen the collet just enough so it will allow the chuck to rotate and just turn the chuck by hand. With the CNC it is easy to go back and tap all the holes in one operation this way.

I have admired the UPT's built by several of the members here and often thought about making one, but I just don't know if I would ever use it.  It is real high on the cool factor though  .

Dave

[gbritnell]

Hi Stew,
A lot of the time when I'm tapping I do it right after drilling in the mill with a tap handle and a spring center but in all honesty when I'm doing very small stuff, 2-56 and below I do it by hand. I have a very small chuck with a plain shank on it. I use this for tapping. I find that I have a better feel for how the tap is cutting. For small taps I don't like anything with a handle. It seems like it's too easy to flex the tap sideways and 'click'.
gbritnell

[sbwhart]

Thanks for the input chaps 

Jo do you me what I call a tapping stand like this.



And thanks for the tips about tapping small holes its something I've been concerned about, I took delivery of the bolts and nuts on Saturday and it comes as quite a shock at just how small they are I guess pound for pound they cost as much as gold 



I have a small chuck that I will press into use for tapping not to sure how I will use it yet I guess that is something I will experiment with.



I'm waiting delivery of some taps and dies I've ordered a packet of ten taps the price is quite reasonable but I'm not sure on the quality only time will tell on that one. I've also ordered a set of ER16 collets with a straight shank holder as I reason this will give me more visibility when I'm milling with the small cutters.

Cheers

Stew

[mklotz]

I do most of my tapping immediately after drilling too.  After all, you'll never achieve better alignment to the hole you just drilled and the mill makes a wonderful, rock-solid, deep-throat UPT.

If you're working with tiny taps consider making free-wheeling guided tap holders like the ones shown on the left in the first picture here...

http://www.modelenginemaker.com/index.php/topic,274.0.html

Note that these, unlike the larger ones on the right, do not have handles.  This provides a good limit on the torque one can apply and the guide rod prevents bending the tap.

[Jo]

Stew, that is the sort of thing  I found the small chuck on the UPT good for the larger taps, with a tee handle fitted.

Against my better judgement the cut down Ellipse pin chuck with an extended shaft and knurled top has proven best for tapping all the way down to 12BA.

The smallest tap holder which is nothing more than a piece of tube with a 10BA screw in the side clamping the tap has not been used yet.

Jo

[Jasonb]

Look forward to seeing this one progress Stew, must say though that you have quite large nuts

I'm also one for tapping after drilling as you know the hole is dead under the axis. My worry with tapping guides is that if a big part is not dead on axis a small tap will want to follow the hole rather than move the part true to the axis. Also as parts are often packed up level you would have to repeat all tha packing again on that little table. 

J

[sbwhart]

Look forward to seeing this one progress Stew, must say though that you have quite large nuts

That's private 

Thanks for the pointers, I like those tapping aids Marv has given the link to I think I'll make one of them when I get the taps, and I'll defiantly tap straight after drilling it makes sense for keeping every thing lined up.

Stew

 

[sbwhart]

Well I've completed the drawings I've marked them up as draft. What I've done is convert Georges' imperial sizes to the nearest sensible metric size and checked that everything will go together I've also drawn it up with a piston valve instead of the slide valve George used as I figure it will be easier to make but as I said that is something we will just have to try out.

I hope to start on it sometime next week, when I've finished the final assembly of my loco, the boiler has passed the pressure test and I'm hoping to do the steam test the week end after next I'll have all my fingers crossed for that one.

For those of you who are interested I've attached the drawing.

[NickG]

Looking forward to this one Stew, loved it when George did it but too small for my clumsiness unfortunately! I'm not totally sold yet on piston valves  being that much easier but I know you've had good success with them.

[sbwhart]

Thanks Nick

The piston valve is a bit of an unknown quantity, we will just have to suck it and see.

Well I've made a start, but the first thing I did before starting to make parts was to get a bit of kit together that I thought that I may need.

I use an ER32 collet on my mill which is fine for normal work, but I've found that with small parts and cutters it tends to obscure the job so I got a set ER16 collets and straight shank holder that I will piggy back on the ER 32



I shortened it by 40mm using a dremell cut off wheel it was too had for a hacksaw.



I made a tap wrench to fit in the chuck and a small die holder for the lathe, I also drilled and tapped few practice holes M1 and turned and threaded a male thread, as you can see in the chunk of ally in the shot

First up the base:-

Square a bit of ally to size.



When making small parts you need a small helper.



 

Mill the pocket in the base



Then mill the middle out and mill the steps



Then drill and tap the M1 holes





No broken drill or taps 

Then profile around the outside



That's the first bit done



Stew