Hello and a part-built blowfly

[Roger]

Aug 29, 2018 5:04:19 GMT Lisa said:

Thanks Kerrin, I'm mostly wondering how many M3 taps it'll take.

Just one I should hope! Time to make that tapping machine that keeps the tap vertical perhaps?

[steamer5]

Aug 29, 2018 8:09:43 GMT Lisa said:

I've found some trying to sell them for $50 each locally. Probably cheaper to ship 'em from the UK if that were the only option.

Hi Lisa,
 Go to the UK for your taps! My Dad got a quote from a place in Aus for a couple of odd ball tap’s (5/16 & 3/8 x 30tpi), he needed for the steam car engine he’s working on.....at the cost he could nearly brought a Rolls! .....he couldn’t find them here.
I found them “ off the shelf” in the UK.....Tracy Tools, usual disclaimer, for 38 pounds, for 1st, 2nd & plug for BOTH sizes plus 15 for freight, I did add a few for me so we split the postage! Delivery was 5 days from memory.

Cheers Kerrin

[simplyloco]

Aug 29, 2018 8:09:43 GMT Lisa said:

I've found some trying to sell them for $50 each locally. Probably cheaper to ship 'em from the UK if that were the only option.

Looking on that famous site I would have thought that the Hong Kong brigade would have something suitable for sensible money. This one perhaps?

www.ebaystores.co.uk/milancentral/_i.html?_nkw=M3+taps&submit=Search&_sacat=milancentral&_sid=220060597

If not, if you cross my palm with silver to cover the tracked postage (£6.95) I can put three of my virtually unused  British made HSS windfall taps - two plugs and a 2nd taper-  in an  envelope and they will be with you in 5-7 days.
John

WP_20180829_10_07_05_Pro[1] by inkaboat, on Flickr

[Lisa]

Thanks John, but I've got a couple on the way to me now anyway (and at a sane price!).

[Lisa]

I've clamped a couple of offcuts to the underside of the milling table to act as stops for the port width, this plus knowing the dial readings at the ends should help keep everything the same length.


So there's one port done, the others drilled out, and the exhaust port looking rather ratty so far:

[Jim]

Looks pretty good to me Lisa. I like your idea for solving the problem of not having stops for the mill table.

Jim.

[Lisa]

Thanks Jim, I was looking at the stop on the Z axis earlier, and I think it'd fit on the dovetails for the other two axis (axises? axii?) as well, if it were possible to get spares. This works just as well of course.

[runner42]

Hi Lisa,

because your Milling Machine is very similar to mine, may I impose on your good instructive capabilities to better understand the procedure you adopted in milling the input and exhaust cut-outs. You appeared to have chained drilled the input cut-outs and then using a slot drill(?) to join the holes to make a continuous slot. You used the off-cuts as end stops for the X axis but how did you provide the same limitation of travel for the Y axis? I would have imagined that limiting the travel in the Y axis was also important.

In addition you had a piece of metal or material one side of the cylinder instead of using both jaws of the milling vise to clamp it. Was the a soft material to protect that side?

Your milling machine has a hand operated clamping mechanism in the first photograph that sits in the centre of the table for the x axis, mine just has a hexagon headed screw for locking, not very practical. How often do you use this? Should I modify my Milling Machine to have a similar clamp?

Brian    

[Lisa]

Hi Brian,

The ports are 5/32" wide (3.968mm) so I've chain drilled them 3.5mm, then used a 3mm cutter (not a slot drill, as the ports are 20mm deep and I couldn't find a slot drill long enough). A cutter will always cut wider than it's actual size, hence why I don't use a 5/32 cutter, also you can get 'dwelling' at the ends when changing directions, resulting in a dog bone shaped port. So my method is to slot them out on the centreline, then take a measurement, then calculate the depth of cut needed to get to the finished size on each side. This is why I don't have stops set there, as the centre line is taken from the dial setting, and the finishing cuts are calculated from there again on the dial setting.
Also, I don't trust a long cutter not to flex, so I slot out the bottom at 3mm with the long cutter, and use a short (regular) cutter to just get the top half to finished size. This may or may not be entirely necessary, and could be overly pedantic, but the result is a parallel port that's within 0.0002" of the intended size, so it works.

I use some hardwood on the moving jaw side of the vice, this protects the job, but also ensures the job is thoroughly clamped in case the job or vice is not quite square; more of an issue when the job was a rough casting, but there's always a chance the moving jaw will lift a little when clamped tight, which the hardwood reduces the chances of this upsetting the positioning of the job (as does tapping the job with a rubber mallet while tightening).

You might notice that handle is rather short; at it's original length it either hit something before tightening, or got in the way of table travel, so I cut a bit off. I'd imagine this is why later models of the mill don't have that handle anymore. So if you decide to add something similar, keep that in mind; just keeping a suitable spanner nearby would likely be just as convenient though.

HTH,
Lisa

[Lisa]

Well that looks rather nice, still need to slot out the bottom half. Also, after a light lapping to take off the felt pen and scribe lines the port face doesn't look quite as flat as it did; quite alright as is though.

[Jim]

The valve ports and surface are looking brilliant Lisa. I'd be pretty chuffed if it was mine.

Jim

[runner42]

Hi Lisa,

thanks for the response. I had to look up HTH, yes indeed it was most helpful. I couldn't have asked for a more detailed explanation.

Brian

[Lisa]

Well that's the exhaust port milled out to depth, only mildly terrifying at 22mm deep (25mm is the cylinder bore), so being cautious not to miscount handwheel turns. I was just going to slot it out with an 8mm cutter, but discovered my only 8mm cutter is blunt, so used a 6mm instead. The bottom is about 0.5-1.0mm undersize all round.



Still waiting for the long 3mm cutter to arrive (could be this week, or next), so I might see about drilling the bolting holes for the steam chest while I wait.

[Lisa]

I've now run out of holes to drill in this setup, though still a few to tap. That's all the bolting holes for the steam chest and frames done.



Meanwhile, the long series 3mm cutter turned up in the mail just as I was finishing drilling, so I won't have to wait to finish this off.

[Lisa]

One down, one to go. Inlet ports slotted to depth, and everything that needs to be tapped is.


Also that odd line on one edge of the exhaust port is annoying.

[Lisa]

On to the next one, this time I've drilled all the holes first, rather than swapping back and forth.


Also noticed the guide lines I scribed in are off centre, so mostly useless.

[Lisa]

The second set of ports are now machined, I still need to finish to depth with a long series cutter though.

Standard and long cutters shown for comparison; 9mm cutting depth compared to 25mm.

[Lisa]

The ports are now done, and I've tapped all the holes for the steam chest studs.



There's a lot of dwelling marks on the right cylinder's port face (can you tell I was milling in circles?) so I might give it a decent lapping to clear that up. I was tempted to skim it with an end mill while it was setup, but the dwell marks aren't deep enough to need more than lapping out I think.
Next I think I'll drill and tap the bolting holes for the cylinder covers, then do the exhaust passages, and finally the steam passages. I'm not entirely certain how I'll do the steam passages yet, as I don't have an angle plate to bolt the cylinders to, and while the head (and column) of the mill can be tilted, it took me hours to get it dead square last time. I'll either do some fiddling with angle gauges, or just tilt the mill head; drilling those last will at least ensure everything else is done before 'unsquaring' the column.

[stevep]

Lisa,

When I drilled/milled the steam passages on my PANSY cylinders, I use a simple 'sine plate' that I made.

Two pieces of 1/2" diameter steel, fixed 4" apart to a plate about 2" wide. Suitable packing and clamping produced the following setup.




Hope that might help.

[Lisa]

Thanks Steve, that 'sine plate' seems rather handy, I might see what I can dig up to put one together.