Quartus

[PaulR]

After spending free time in the last day or two drawing up plans for my fourth little bar-stock engine (since buying a new lathe back in December), I've got enough of the essentials in place to start building. This will be another rotary valve engine although the valve will be rotating 360 deg rather than oscillating back and forth like the last one. It'll also be in a vertical orientation just for a change.

I decided to make the support column and piston rod guide-bracket first. The bracket needs some fixing holes and the rod guide hole; think I'll do the latter in the lathe as my drill's accuracy is unreliable.

Look on my works ye mighty and despair 

[Admiral_dk]

Look on my works ye mighty and despair 

    

Per     

[PaulR]

Fully intended to do some more on this today but decided to spend the time making some widgets I'll need instead. First a screw plate for the common metric sizes I'll be using - will make some smaller threaded holes when needed (excuse the odd spacing - reused some holes) and second, a cross-drilling widget for 2 and 3mm holes in 8mm rod. Tested that and it works but might make a second part to clamp separately so it can be slid along or rotated 90/180 to drill a second hole without losing alignment. It will also have a grubscrew not this cap head, so it can be fully held in the vice. Also need to make one for 6mm rod.

Also sharpened and hardened one of the cheapo punches I bought a couple of months ago and sharpened the pointy end of my Jenny calipers.

[redhouseluv]

Dumb question

What's a screw plate used for?

[PaulR]

Dumb question

What's a screw plate used for?

Shortening screws - screw through and file off. Welcome back!

[redhouseluv]

Ah ..... I see, that is a good idea; can it somehow be modified so it can be used for making them the same length too, that is something I always have trouble with for both bolts and studs?

[PaulR]

Ah ..... I see, that is a good idea; can it somehow be modified so it can be used for making them the same length too, that is something I always have trouble with for both bolts and studs?

I've seen some other fancy solutions in the past, mostly to stop the screws rotating while filing, but the basic plate suits me. Maybe put the same number of washers or nuts on the screws before screwing into the plate? But then again, the plate won't suit everything - I used 6mm thick steel but sometimes need shorter screws, especially grub screws (for those you can put a hex wrench in the screw and clamp that in the vice instead of the plate).

[PaulR]

Finished off the guide bracket at the top, except for the 3mm hole - I'm waiting on a reamer for that (temp screws holding it). Faced the cylinder and valve blocks to length and reamed the hole for the valve.

[PaulR]

Made the cylinder bore after spending far too long chasing the last 0.001" getting the block centred; every time I got within a gnat's whisker I managed to bump the DTI and had to start over. Ho hum. Anyway, it came out fine so now I can do the valve block spigot and other holes.

[PaulR]

Just about finished the drawing today and once again I seem to have ended up with a (miniature) giant stompy robot! Even has eyes and a poop tube this time 

[PaulR]

This evening I just had time to turn the top of the valve block down to fit the bore. Nothing interesting to see but I'm really please with the fit and alignment. Oh, also turned the valve itself to the right length ready for drilling but need to make another cross-drilling widget first.

[PaulR]

Spent quite a bit of time drilling and plugging the air passages in the valve and valve block this evening. There's little to see as most of it's hidden from view but after all that tedious drilling, dammit I'm going to post some photos 

Here's a temporary screw in the air inlet hole with the admission and exhaust holes on top of the block. The hole in the valve is the inlet, there are two on the other side of it that lead to/from the cylinder.


Here's the plugged holes in the bottom of the valve block (easy to see) and in the end of the valve (not so easy to see  )


Looking down the cylinder. The two holes are marginally off axis relative to the valve but I don't think it'll make any difference as I used the holes to transfer to the valve so that has the same error.


The bits placed in position showing the exhaust hole in the valve.

[redhouseluv]

Spent quite a bit of time drilling and plugging the air passages in the valve and valve block this evening. There's little to see as most of it's hidden from view but after all that tedious drilling, dammit I'm going to post some photos 

Send photos, someone will look at them for sure, I have!

[Jasonb]

And me.

[PaulR]

Made the inlet tube at bottom left (there will be a bit more space under it as I plan on putting it all on a 1/4" thick base), faced the piston to length and drilled through it, drilled the cross-hole using the newly created widget - worked a treat - and got the cross bar thing ready to solder in. Stupidly didn't follow my own method for making this part despite having written the steps down in the plan I meant to fit the cross bar first then drill through. As it stands, after soldering I'll have to drill through again, hopefully that won't cause any issues but I'll be putting some tape around the cross bar when the assembly goes back in the chuck just in case the solder decides to let go!