Author Topic: PM Research #4 - Quarter Horse Vertical Steam Engine  (Read 16098 times)

Offline Dave Otto

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Re: PM Research #4 - Quarter Horse Vertical Steam Engine
« Reply #30 on: April 17, 2022, 12:11:58 AM »
Nice progress Stuart, I have been enjoying seeing your setups and thought process.

Dave

Online crueby

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Re: PM Research #4 - Quarter Horse Vertical Steam Engine
« Reply #31 on: April 17, 2022, 02:09:26 AM »
Impressive work - that engine is so much bigger than I'm used to, and the long legs must make things a lot harder. Well done!

Offline propforward

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Re: PM Research #4 - Quarter Horse Vertical Steam Engine
« Reply #32 on: April 17, 2022, 02:01:14 PM »
Thanks all!

Those long legs did present some difficulties. As chunky as the castings are, when presented to a cutting tool those legs have a lot of flex. Left unsupported it's quite amazing how much they move about. Bolted down that casting looks like a bow legged man, kinda sorta.  :headscratch:

I might be laboring a bit on some of my setups, but the results seem to be coming out where I want them - and I am really enjoying making this engine, I am having more fun in the shoppe of late than I have ever had.

A few fiddly bits today I think, then I may start work on the cylinder.
Stuart

Forging ahead regardless.

Offline RReid

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Re: PM Research #4 - Quarter Horse Vertical Steam Engine
« Reply #33 on: April 17, 2022, 02:54:17 PM »
Quote
I might be laboring a bit on some of my setups, but the results seem to be coming out where I want them - and I am really enjoying making this engine, I am having more fun in the shoppe of late than I have ever had.
Getting good results makes it more fun. Getting good results in machining often means much more time is spent in prep and set-up than in actual execution. Embrace the ratio! :cheers:
Regards,
Ron

Offline propforward

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Re: PM Research #4 - Quarter Horse Vertical Steam Engine
« Reply #34 on: April 17, 2022, 09:43:40 PM »
I quite agree Ron, it's very fulfilling when the time put in to set up pays off.

So by the time I was done with video calls to my family in the UK it was a late start to machining today. Fine with me, I was talking with my Dad in Scotland, and he also makes model engines. Our calls usually consist of a good hour of holding parts up to the camera and discussing set ups, it's great having this technology to connect us.

Anyway, I turned a few parts.



Nothing too remarkable there. I have finally learned to chamfer parts on the backside before completing parting off operations, which saves trying to grip awkward parts.



A neat trick that everyone else already knew!  :Lol:

I've been measuring up the cylinder with a mind to starting that next, but there are a few challenges on it that I haven't worked out yet, so I made a start on the bearing blocks instead.

Now, the bearing cap is cast as part of the pillow block, which is handy. I think I will leave the caps attached until some of the features are machined in - that will make holding them a bit easier.

After measuring these, I discovered that there is literally no machining stock on the underside of the cap, but they need to be skimmed flat. I decided to clamp the castings to the table, and just dust off the top of the pillow blocks to get good, flat surfaces, that should be quite parallel to the undersides.



Just .015 removed.



Then I set up the vise (getting good at getting that trued up quickly). I use a piece of scrap spring steel to hold parallels in place.


I clamped the castings in place, and then touched off on multiple locations to get a feel for the flatness of the casting surface.




Amazingly the variation is about 0.012", which is pretty impressive really, and that is all that I removed from that surface.



As you can see, the stamped in part numbers are not quite removed, and that's fine. There is also a little roughness near the casting gate. Again - unimportant. I can't afford to remove any more from the bearing caps and maintain a good appearance, so this will do for now.

So that's where they are at - next phase will be to get the pillow blocks to the right height ( plenty of stock on those - .079 left to go), and drill and tap holes. I think I will do it by clamping these parts to a flat aluminum plate, so that I can put the through holes in the bearing caps in place in the same set up. Then I can cut the caps off, clean up flash, bolt the caps to the blocks and machine sides and get ready to bore the crankshaft bearings. That will likely be done by bolting the bearings to the base and boring through both bearings in the same operation.



That aluminum plug in the lower half of the picture is a plug I made to test the bore in the frame. The bore seems to be quite straight with no taper which makes me happy. The plug also serves as another means of verifying the ID before making the slider.

« Last Edit: June 18, 2022, 03:03:12 AM by propforward »
Stuart

Forging ahead regardless.

Offline RReid

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Re: PM Research #4 - Quarter Horse Vertical Steam Engine
« Reply #35 on: April 17, 2022, 11:16:41 PM »
Quote
I use a piece of scrap spring steel to hold parallels in place.
Nice trick. I'll remember that one.
Regards,
Ron

Offline propforward

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Re: PM Research #4 - Quarter Horse Vertical Steam Engine
« Reply #36 on: April 17, 2022, 11:20:35 PM »
The banding straps from crates is ideal stuff.  :ThumbsUp:
Stuart

Forging ahead regardless.

Offline propforward

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Re: PM Research #4 - Quarter Horse Vertical Steam Engine
« Reply #37 on: April 24, 2022, 06:13:53 PM »
Latest part here - lower valve head. It was supposed to be two parts, but the second one got screwed up because yours truly didn't pay close enough attention to the drawing.  :facepalm2:

Anyway, a few shots of the process. Not much to say about it - the key feature was the backside step diameter which is called out at .624 +0 / -.001, so I was keen to hit that. That diameter locates the valve head in the reamed valve bore, so I was keen to machine that in the same set up as the reamed thru hole.



So, simple enough really. Clean up the OD, turn the boss for the 3/8-24 thread. I added an undercut feature at the back of the boss for the thread to run off to - cleaner in my opinion. Then I elected to use a grooving / parting tool to make the .624 step. The thru hole was of course drilled and reamed as shown on the drawing.

Clean up



Boss



Undercut and start of the backside step. The backside was opened enough so that I could get my calipers in there.



Finished backside step prior to cutting the thread.



Then over to the mill for the bolt pattern



Which I located using the DRO bolt hole function. I rather like that feature. Alignment to the bore was achieved by using a gauge pin to find the center.





And there we are. Not a very dramatic part, but it came out well and very accurate. Every dimension is within .001. Decent finish too - the way this steel cuts I'm pretty sure it's 12L14.



Out of time now unfortunately. Shame about messing up the other part. It would still work even with the one dimension off but I can't have that, have to remake it. If it was an expensive casting I might live with it but since it's just a matter of a short piece of steel round bar that I have plenty of - got to do it over.



Stuart

Forging ahead regardless.

Offline Baltic

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Re: PM Research #4 - Quarter Horse Vertical Steam Engine
« Reply #38 on: April 25, 2022, 04:49:47 AM »
Great Job, I like your set-ups, and the spring steel idea I will pinch,  :)
Did you single point cut the 3/8 thread?

Thanks Gary

Offline propforward

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Re: PM Research #4 - Quarter Horse Vertical Steam Engine
« Reply #39 on: April 25, 2022, 08:32:04 AM »
Thanks!

I used a die for this thread, since I had one available, although I wish I’d single pointed the thread, just for extra sense of achievement. My threading tools are all quite large though and won’t get in very close to the shoulder, so I need to make one more suitable.
Stuart

Forging ahead regardless.

Offline propforward

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Re: PM Research #4 - Quarter Horse Vertical Steam Engine
« Reply #40 on: April 30, 2022, 08:20:48 PM »
A couple more parts made. Nothing too fancy, so no need to do much description.









I think I may get back on to the bearings next, that will be a little more involved.
Stuart

Forging ahead regardless.

Offline propforward

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Re: PM Research #4 - Quarter Horse Vertical Steam Engine
« Reply #41 on: May 01, 2022, 10:55:05 PM »
I thought I would quickly make the eccentric.

Well - quickly went out of the window almost immediately.

The process started easily enough. Skim the OD clean, then use a groove tool to make the diameter and rims.



This cold rolled that PM Research supply has to be leaded steel, it turns really easily.

A bit more.



Rubbish picture here, but shows the process. I don't know if it's accepted practice, but I started by taking bites out by feeding the groove tool in like a parting tool, indexing over, take another bite and so on, then turn off the last material by starting one end and feeding the groove tool along the surface. Did not seem to cause issues and the part came out well.





I then moved the part over to the mill and set up to drill the offset hole.

Here I am indicating the side of the machined diameter to make sure it is square up and down.



I realized after drilling pilot holes that I do not have a drill big enough to clean out most of the ID for the eccentric hole. It has to end up at 5/8. I have a 5/8 reamer, but no drills. Of course, I could bore out the hole on the mill but I've never done that, so I feel more comfortable boring on the lathe. So - to the 4 jaw chuck.

Initial centering by eye to get close:



The hole is 1/2" at this point, so I used a gauge pin for final centering.



Then I ran into difficulty. I chose to center on two positions on the gauge pin but I could not get both positions to run true. I spent a lot of time on this, and in the end decided that I probably did not have the part straight in the mill vise. What to do?

After spending some time watching joe Pieczynskis set up videos on youtube, I changed my approach. Since the face of the part and the OD were machined in the same set up, it's reasonable to assume they are square to each other. I therefore indicated the face to make sure it was true. It wasn't - so a few taps got that true.

<a href="https://www.youtube.com/watch?v=kU6pVSixjv0" target="_blank">http://www.youtube.com/watch?v=kU6pVSixjv0</a>



I verified the part was true by indicating along the length of the OD on the crown - I did this with both indicators and there was no measurable change.



Then I indicated the gauge pin right next to the face, and adjusted the part to get it concentric - this is to position the bore center as accurately as possible.

I did a few iterations of that until face run out and pin runout at the face were within .0005", and no noticeable taper on the OD crown.

And then turned the bore ID to the drill size called out on the drawings.





Then I went to mount my 5/8" reamer in the drill chuck.

Oh.............of course my drill chuck doesn't go that big.  :hammerbash:

So there the part sits while I decide what to do next - which will most likely be to procure an ER40 morse taper 3 collet chuck (since I have ER40 collets). If I didn't already have the reamer I would just machine to size - but I've been planning to obtain an ER40 collet chuck for the tailstock anyway.

Oh well - that's it for today.
Stuart

Forging ahead regardless.

Online crueby

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Re: PM Research #4 - Quarter Horse Vertical Steam Engine
« Reply #42 on: May 01, 2022, 11:00:08 PM »
I've used that same technique with the parting tool, learned it a while back on one of the threads on the forum.
For the bore in the eccentric, why finish with a reamer? I usually just take light cuts with the boring tool till its the right ID. Last passes without moving the cutter out, just run it in and out to smooth up the tool marks.

Offline propforward

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Re: PM Research #4 - Quarter Horse Vertical Steam Engine
« Reply #43 on: May 01, 2022, 11:34:38 PM »
For the bore in the eccentric, why finish with a reamer?

Mainly because I already have it, but that's just being bloody minded. I think I will finish it up exactly as you describe, which sounds like a fine approach. I have HSS inserts for that boring tool, I'll probably dress the edges on the insert and then go at it as you describe, and get just as good a result. A case of not seeing the wood for the trees, while I wandered around fixated on the reamer I already had.

Thanks Chris for the suggestion - very much appreciated!
Stuart

Forging ahead regardless.

Offline mikehinz

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Re: PM Research #4 - Quarter Horse Vertical Steam Engine
« Reply #44 on: May 01, 2022, 11:52:03 PM »
For the bore in the eccentric, why finish with a reamer?

Mainly because I already have it, but that's just being bloody minded. I think I will finish it up exactly as you describe, which sounds like a fine approach. I have HSS inserts for that boring tool, I'll probably dress the edges on the insert and then go at it as you describe, and get just as good a result. A case of not seeing the wood for the trees, while I wandered around fixated on the reamer I already had.

Thanks Chris for the suggestion - very much appreciated!

Stuart,

I use a carbide insert tool known as a groove/turn/part tool all the time and I think it's the same as yours.  I have one tool that's 2mm wide and another one 3mm wide.  I make wide grooves all the time by moving the tool sideways and it seems to do just fine as long as you take fairly light cuts.  I tend to use the wider tool, if possible, on the theory that's stronger when side loaded.

For your bore, I wouldn't hesitate to do that with a boring bar.  In fact, I do that all the time.  I'll use a boring bar just about every time if I can vs a reamer, particularly as the hole sizes get larger.  Big reamers are NOT cheap!

It looks like you're making great progress!  I'm enjoying watching.

Mike

MIke
Wichita, KS, USA

 

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