Muncaster's Joys Valve Engine

[Jasonb]

I'm not bored

[Kim]

Simon, you're certainly not boring me!  Though I'm fascinated by all the projects people do here, I learn the most when people describe what the do in detail.
But it does take time, I understand that.  So do what your heart moves you to do.  Just know that there are people out here (like me) who are reading your posts and find them very interesting!
Thanks Simon,
Kim

[Don1966]

That's a great project Simon and indeed a very interesting project. You have my attention bud, nice work.

Don

[tvoght]

I'm watching every step Simon and enjoying your great work. A little longer-winded wouldn't hurt anything in fact.

--Tim

[vcutajar]

I am not bored Simon.  Keep up your descriptions and good work.

Vince

[smfr]

Glad to hear that you're not all bored to    The never ending saga continues...

As promised, today was "muck with the 4"x3"x2" lump of cast iron" day   

It's important that the faces end up at right angles to eachother, and I didn't quite trust my vise's fixed jaw to be perfectly vertical, so I started out using an angle plate to hold the block:



Crust was taken off with a roughing mill, additional material with a 5/8" end mill, with the final few thou via the flycutter (here's an action shot!). That's a fair amount of reach for the toolbit, and I did get a bit of singing, but nothing too serious. I was getting nice cross-marks from the flycutter too, indicating that my milling column is trammed correctly.



When it came time to cut a second surface that had to be perpendicular to a finished surface, I spent some time faffing around with the angle plate and an indicator, since there was a discrepancy between setups that I did on the surface plate and after bolting down on the milling table. I had a "this feels wrong" moment when I started shimming between the block and the angle plate, even though I'd already checked the angle plate for accuracy. Finally I gave up on the angle plate, and just went back to my screwless vise (which is a nice toolmaker-made vise, so I should have trusted it all along  ), and the sides ended up nicely perpendicular.

However I did have a minor problem when doing the ends in the vise; all that height gave a lot of leverage from the cutting forces, and the block moved. A business-card shim helped:



There's a bit of a ding, but luckily it's on the side face that gets taken down later anyway to make room for cladding.

So here we are, in situ:



It's within a few thou on all dimensions and nicely square 

Now, how to bore? The cylinder length, at 3", is longer than my quill extension, so boring in the mill is out. That leave the faceplate, or using the carriage. I contemplated the faceplate:



but that's an awful lot of iron to have swinging around, and I couldn't see how to clamp it down. So I'm going to bore on the carriage:



I spent a lot of time getting everything lined up, and using the adjustable parallels to get the correct center height. Then I realized that I didn't have a plug gauge to check the bore size, so to avoid the tempation to just wing it, I tore the setup down (after thinking about it for a few minutes  )

Tomorrow I'll turn a dummy piston, then set this whole thing up again. I think I'll also make a steel bar to replace that bit of Al across the top; I'm worried that the drilling forces will cause the part to tilt up, so I need it firmly clamped down!

I also contemplated making a boring bar driven by the chuck and supported by the tailstock, with a bit of tool steel and a grub screw adjustment, but then realized that I could use my small boring head and get just enough offset. Let's hope that works, so I don't have to tear down this setup mid-boring!

Simon

[Jo]

I spent a lot of time getting everything lined up, and using the adjustable parallels to get the correct center height. Then I realized that I didn't have a plug gauge to check the bore size, 

Sounds like you need a second lathe 

Watching with interest. I do like those Vise mounting clamps I think I have commented on them before.. I think I need to make a set for Sexy 

Jo

[Florian Eberhard]

Hey Simon

I would use the boring bar.  The probability of getting any vibrations with the boring head is quite higher compared to the supported boring bar.
(Stability with support is around 16 times higher than without !!!)

Regards
Florian

[Jasonb]

Yes I'd also go with the between ctrs bar, the boring head over that length may chatter and /or give a tapered bore.

Regarding the drill tilting the work as you drill, you can bring the tailstock upto the back of the block and apply gentle pressure to keep it in contact as you drill which balances out the forces.

J

[sbwhart]

Simon

Another way to bore a twin cylinder block is to use an angle plate attached to your lathe face plate provided your lathe has enough swing. Like this





You just reposition the angle plate for each bore without taking the cylinder off the angle plate that way they must be square and parallel to each other.

Using the lathe bed method as you plan is just as good provided your set up is up to it.

Keep up the good work

Stew

[tangler]

Simon,

Plus 1 for the between centres boring bar.  These can be tricky to get an exact bore size but I suggest that the bore in the cylinders are nominal and you will be making a piston to fit.  When drilling through prior to boring I'd go a stage further than Jason and use the tailstock to push the job with the saddle free.  That way all the forces are axial and the tailstock is designed to take it.  The forces when drilling are much greater than any generated when turning.

I sometimes share you concerns with my Wyvern build that we are posting into the void but I have decided that people are reading even if they don't comment - I know I don't comment very much and there are only so many times you can type "Way to go - still watching and learning"

So, way to go Simon - still watching and learning 

Cheers,
Rod

[Stilldrillin]

Simon,
I sometimes share you concerns with my Wyvern build that we are posting into the void but I have decided that people are reading even if they don't comment - I know I don't comment very much and there are only so many times you can type "Way to go - still watching and learning"

So, way to go Simon - still watching and learning 

Cheers,
Rod

Simon, Rod.

"Way to go - still watching and learning".   

From, one of the Quiet Majority.......   

David D

[smfr]

Thanks for all the good advice! The between-centers boring bar wins  I'll have to see if I have any stock of the right size; I need about 7/8" I think, since my drills go up to 1". I'm thinking of a making a 40TPI grub screw, which gives 25 thou per turn (which also means that I'll have to find or make a slotted screwdriver with a bend, for easier eyeballing of angle. I think a cheap screwdriver is going to have a date with Mr Vise). For a toobit, I have some bits of what I think are carbide (but no green wheel to grind them), or maybe an ex-end mill or drill will provide.

Stew, thanks for the suggestion of the angle plates. I'll have a play later, but I don't think mine are wide enough to get enough bolts around to hold things.

Also, pushing with the tailstock when drilling: good idea! 

Simon

[smfr]

Sounds like you need a second lathe 

I wish! First I'd have to move house to get more room

Watching with interest. I do like those Vise mounting clamps I think I have commented on them before.. I think I need to make a set for Sexy 

They work OK, but the limited room on my milling table limits my options. First, I wish I'd made them from steel. Second, there isn't a lot of material holding the pin that slots into the vise holes, since the gap between the vise side and the table slots is small. This hasn't been a problem so far, but I can imagine that over-tightening them could deform the clamp and loosen the pin. I did consider a design that pivoted on the other axis, but I think I rejected it because it didn't work if I wanted to place my vise in the other orientation (which is also why these clamps have slots, not just a hole).

Simon

[swilliams]

Looking forward to seeing more about the cylinder boring Simon. Looks like a fun job, hope it turns out well.

Steve