Author Topic: Elmer's #33 - a novice makes chips  (Read 39101 times)

Offline Don1966

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Re: Elmer's #33 - a novice makes chips
« Reply #30 on: December 27, 2012, 03:56:58 PM »
Enjoying it as well here. Yes keep your photos coming.

Don

Offline Thayer

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Re: Elmer's #33 - a novice makes chips
« Reply #31 on: December 28, 2012, 07:45:58 AM »
Here's a pretty quick bit. I knocked out the valve plate, steam chest cover and valve nut from some 1/16 K&S brass from the local hobby shop. Since the Z isn't all that critical on a job like this, I just clamped the stock to a scrap of wood that I held in the vise.

Step one, after the layout and setup, was to run around with the center drill and make a few divots. I think by the time I actually took this photo I had also chased the holes through with the appropriate sized drill bits.



This is pretty much the same thing, though this time with the valve nuts tapped. I am finding my little piece of printer roller bar makes a dandy tapping guide, see above.



Next up is making swarf. Awfully pretty from brass, despite this mystery metal giving me some fits. This was the first time I actually broke an end mill in a while. I was using the same feeds, speeds and tool as with the 360 for the nuts earlier, yet the K&S sheet got all gummy and snapped the carbide mill after only a few inches. Fortunately I had a spare and juggled the feed with Mach3's manual override and dialed the rpm around a bit by hand/ear/eye until everything was happier. Yes, there are 4 parts under those chips. I didn't bother keeping the area clean as I knew I was going to be dressing the parts a bit after milling.



I stopped the Z move about 15 thou short of breaking free to keep the parts attached to the parent stock. I then did some quick flexing to fatigue the parts free.



A pair of heavy duty scissors got rid of most of the flash and a few strokes of a fine file, followed by a little oiled 400-grit wet or dry, left the parts in the condition shown below.



Not tough, but still it's three more parts checked off the list. I doubled up on the valve nut as there was room on the stock that would otherwise go to waste and the part is small enough I don't want to bother fighting the workshop troll for it if I drop one.
« Last Edit: December 28, 2012, 07:50:53 AM by Thayer »

Offline Thayer

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Re: Elmer's #33 - a novice makes chips
« Reply #32 on: January 01, 2013, 08:58:00 AM »
Happy New Year, all.

Yeah, it's late and I should be in bed by now, but I am also a bit behind on my posting, so here goes a little update on my #33, specifically, my effort on the steam chest.

Here's the rough blank, a bit oversize. My stock was 1/2 x 3/4, so there was plenty to remove.


The first thing I did was clean up the ends. I wrote a little g-code to move back and forth in Y, while stepping over a little bit in X on each pass to clean the face. When setting up for a cleaning cut like this I position the tool near the stock, drop the spindle down so the tool tip is well below the surface and slide the stock against the cutting edge. I rotate the spindle at least a turn backwards by hand to make sure that I am actually referencing the cutting edge before I lock down the vise and set my X0 in Mach3. It isn't that big a deal on stock this thick, but on thinner material it is rather too easy to reference the tool in the flute and end up with a massive first cut.


And a few seconds later the end looks like this. As before, note the aluminum packing material to balance the far end of the vise.


Once the stock was clean on both ends I clamped it in the center of the vise and used the endmill to reduce the faces to the final 0.250 thickness. A bit of Dykem on the face and layout with the height indicator had it ready to go in the 4-jaw for drilling. I protected the faces of the blank using some aluminum scrap, but the stock is still wider than needed so I have some "factory-original" padding that I can grab on the sides. The indicator is referencing a piece of drill rod that I chucked in the lathe and turned to a 60 degree point. I gave it a clean shoulder at the same time to keep it concentric with the tip and provide an accurate surface for the indicator to reference. The other end is center drilled so I can position it between a live center in the tailstock and the block to center up the hole for the valve rod and packing nut made earlier. Centering at this point isn't critical, but I still clocked in the 4-jaw as accurately as I could using this rod and the indicator mounted to the cross slide.


Once I had the stock centered, I deep drilled it with a #41 drill for the valve rod. That actually requires two drills as the main rod is .086 for most of its length with the very end at 1/16 where it references the far end of the steam chest.


Elmer also calls for the 1/16 bore for the rod to be "close" so I drilled the last 1/4 inch at .059 and then reamed it to 1/16.


Next was the #21 tap drill for the packing nut ...


... followed by the tap.


Next I moved the chuck to the mill and wrote another little "back and forth" code that dropped the Z on each step to remove most of the stock around the threaded spigot. The target line is the top most obvious layout line.


Almost half way down on the first side, as seen through the chip guard.


And with both sides roughed out.


Here I'm starting to turn the spigot.


And chamfering after turning it down to final dimension.


The other end needs a spigot for the end of the valve rod, so I flipped it around in the chuck, clocked it back in with my indicator and tipped rod, and again, wasted away most of the stock with the mill before turning it down. The center hole on this end was much shallower, so I didn't have much to turn off.


This end gets turned round, so I roughed it down with a Mark 1 eyeball chamfer and then...


... got busy with a file. What I didn't do was read the print properly. The actual diameter on that end doesn't matter but Elmer intended it to finish at 3/16, not the 1/4 I left it at here. After I finished the entire part, and realized my oversight, I went back and reduced this a bit more. And then filed the end round again. You will see the smaller dimension later.


Thinking I was done with the turning at this point, I pulled it out of the chuck and moved back to the mill to drill the mounting holes.


Remember how I said I can be a bit chicken at times? Here is one of those times. I referenced the steam chest location with my stop, then swapped out the part for a piece of wood to test my g-code for the inner pocket.


Apparently I am still living clean enough. The test looks good and aligns with the layout on my block, so that only means one thing.


Yes, time to be a chicken again!  I couldn't help myself and made a first pass on the pocket at .001.


That looked good too, so it was time to go deep. Here is the valve pocket milled through and just showing the hole for the end of the valve rod.


Everything looks good in the end. I've now also cleaned off the extra width and turned the rounded end smaller.

« Last Edit: January 01, 2013, 09:05:15 AM by Thayer »

Offline NickG

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Re: Elmer's #33 - a novice makes chips
« Reply #33 on: January 01, 2013, 10:24:28 AM »
Great work, this is looking very nice indeed.  :ThumbsUp:

Offline steamer

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Re: Elmer's #33 - a novice makes chips
« Reply #34 on: January 01, 2013, 01:10:33 PM »
Great approach Thayer....measure twice, cut once!

Good Job!

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline b.lindsey

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Re: Elmer's #33 - a novice makes chips
« Reply #35 on: January 01, 2013, 02:54:05 PM »
Just catching up on this build Thayer. I too enjoy seeing what others are doing with Sherline equipment...CNC or manual. Its looking great so far!! Excellent pictures too btw!!

Bill

Offline Don1966

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Re: Elmer's #33 - a novice makes chips
« Reply #36 on: January 01, 2013, 03:40:24 PM »
I ilke your approach, I also am cautious and do dry runs. I have used a pencil once and that didn't work to good the point kept breaking. Looking good Thayer.

Don

Offline vcutajar

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Re: Elmer's #33 - a novice makes chips
« Reply #37 on: January 01, 2013, 04:10:34 PM »
Thayer

Great build thread.  :ThumbsUp:

I love you setup photos and good-humoured descriptions.  Keep it up.

Vince

Offline Thayer

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Re: Elmer's #33 - a novice makes chips
« Reply #38 on: January 01, 2013, 05:37:12 PM »
Thanks for all the feedback guys. I am working largely in a void and making it all up as I go along with techniques gleaned from books and the internet. I would love to have a cnc lathe as well, but I think for most one-off type stuff like this a manual lathe makes more sense.

Thayer

Offline Thayer

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Re: Elmer's #33 - a novice makes chips
« Reply #39 on: January 04, 2013, 05:44:01 AM »

Well, if you have a steam chest core with a valve, valve plate, nut and cover, it must be time for a valve rod to drive it all.

Here I am roughing out the 1/4-inch stock using a sharp HSS tool and a live center. I ground the tool specifically for this project and it is holding up well. Getting that right end down to a useable dimension is tough with the center right there. On some projects I'll rotate the tool a bit and cut backwards though here I had enough excess stock and just worked as close as I could with the angles shown.

Doing some backside cleanup with a rounded finishing tool mounted in my compound slide. It is tough to see but I like the flexibility that slide offers.




Here I am trying to get as close to 1/16 as I can on the pin end of the rod using my finishing tool. I did okay on this one. In the end it mikes at .0623 with a nice finish. I'm afraid I've overshot enough to know it was more luck than skill.


The rod is rather flexible for single pointing a complete thread and I still don't trust my math on threading. I don't have a follower and didn't want to make one up, so I got it started with a sharp tool then cut the flared end off to finish it with a die.


I started the die in the holder now pushed back to the right, then let it spin fwd as the holder wasn't deep enough to accept the pin.


The pin end was a bit long to the drawing as well, so I used my steady rest to trim and smooth the end to length. It may be within a few tenths of the right diameter, but it is now .040 too short. Drat! That will still work out though, as near as I can determine. I may end up lengthening the eccentric rod a little to make up for it.


The other end needs a 1/16 slot to make up with the eccentric rod. I pulled the rod from the chuck and moved to the vise on the milling machine. The rebate in my vise jaws were perfect for this hold. I predrilled the ends with an #50 drill.


Pre drilling the ends gave a lot of relief for the 1/16 end mill as I then plunged at the ends .010 for each pass back and forth. I used my edge finder on the smaller turned section to find the center.


After slotting I used a little more back and forth code to face the sides parallel with the slot. I think I took .003 off on each pass on the sides. The total reduction is only .015 per side so it really didn't take long.


This next setup has a lot going on. Most obvious is that I needed to rotate the rod 90 degrees to cross drill it for the retaining pin. I already know where the slot is, so how to do that without losing my x reference? Well as you can see, I used my work stop against the rod end. I know that's an easy and obvious solution, but for us beginners it usually only comes with the hindsight afforded by a quarter turn CCW on the vise screw. The shank of my 1/16 bit is a close fit in the slot and allowed me to ensure that I rotated it accurately. Finally, the edge finder comes back into play to accurately locate the center of the flat face. You can't assumer that the part is concentric with the parent stock since I used a 3-jaw to turn it.


The hole is located plenty close enough for my eye. Elmer calls for a close dim here, so after drilling a few thou under, I ran it through with a 1/16 reamer.


Back to the lathe now, and I went right to the 4-jaw so I could dial it in closer than I can get with my 3-jaw. That really wasn't necessary, as I really was only parting it off of the parent rod.


Once it was clear I used a 3/16 collet to hold the head while I finished the rough end. I took very light cuts as I was working into the slot and didn't want to muck it up.


Here are the results, along with the pin that I will detail below.


Offline Thayer

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Re: Elmer's #33 - a novice makes chips
« Reply #40 on: January 04, 2013, 06:05:10 AM »
Since the valve rod pin is shown above I certainly can't pretend it isn't done and go to bed at a reasonable hour, now can I? Nothing to do but carry on.

The parent stock for the valve rod is still in the three jaw, so let's make the pin from a little further on down the same.


Roughed out to final diameter on the pin and head, left long for parting off and cleaning.

Off to the vise to cross drill. As above, the edge finder, my micrometer and a few buttons on the calculator let me find center on the rod.


Might as well skip the math and just use the valve rod to ensure adequate clearance on the hole. Elmer calls for a #70 drill here, but the closest I come with the mini carbides is #74 @ .0225. Still plenty of room for a strand of copper wire, so I'm off to the races.

I learned my lesson above and returned it to the 3-jaw after cross drilling. Note the reference Sharpie mark on the stock. It's tougher to see, but there is also one on the jaw face, made at about the same time. That's close enough for parting off.


Note here that I have also shortened and dressed the end outside the hole. Yes, the lathe was spinning for this shot, but I did back the tool off a few thou to avoid rubbing.


Here I have reversed it in a collet to dress the head. Must have been close on this diameter as well, as it cleared the reamed hole in the valve rod and was a light finger-press fit in the 1/16 collet.

Everything needs a bit of a bath, but here it is, installed with enough room for a thin washer.

Yeah, that's the packing nut screwed into the valve chest.  What's another few minutes, since we are on a roll?

Offline Thayer

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Re: Elmer's #33 - a novice makes chips
« Reply #41 on: January 04, 2013, 06:31:25 AM »
All the valving / steam chest bits waiting for a home.


Coming together...


And on the cylinder block.


I agree, the oversize washers and SHCS look awful and they will go away. I made my first 2-56 test nuts today from some 1/8 hex stock and they look pretty good. Do you see any issues with making studs from 360 brass to match the heads and nuts, or should I go to 12L14? As much as I could try to justify a low-time guy like myself using Du-Bro's threaded rod, I don't think I can bring myself to do it.


Yes, I know there is no way to get steam into the chest yet, but that will wait until I decide if I want to come in through the chest proper or its cover. Okay, the chest does make the most sense, since an engineer would want to be able to set the timing without undoing the feed. So now that I have sorted that out, it will just be a matter of where/how to feed it once I assemble it all.

Good night, all.

Offline NickG

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Elmer's #33 - a novice makes chips
« Reply #42 on: January 04, 2013, 09:13:19 AM »
Looks perfect. I was looking at elmers drawings at 1am - couldn't sleep. Does anyone see the point of the valve plate? Apart from if some if the ports are messed up you don't have to scrap the whole cyl, just the plate to do again.

Offline zeeprogrammer

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Re: Elmer's #33 - a novice makes chips
« Reply #43 on: January 04, 2013, 11:35:58 AM »
That's looking pretty sharp. The finish looks excellent.

You mention in the last post about the parts 'needing a bath'. What does that mean?
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Offline arnoldb

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Re: Elmer's #33 - a novice makes chips
« Reply #44 on: January 04, 2013, 11:53:41 AM »
That looks good Thayer  :ThumbsUp:

As to using brass for the studs: it should be OK; just don't go overboard when you tighten the nuts.  Some steel or stainless steel would be preferable for strength.  I've also used bronze brazing rod for studs a lot; it's a lot tougher than plain brass and makes great matching-colour studding.

Nick, on this engine the valve plate is not that critical.  If the engine block is aluminium, then it definitely does help to provide a better sliding surface for the valve.  Just beware, on some of Elmer's other engines the holes in the block does not quite match the valve plate layout.  For these, you do need the valve plate to get the correct valve port geometry, so have a good look before you decide to go without the valve plate.

Kind regards, Arnold

Building an engine takes Patience, Planning, Preparation and Machining.
Procrastination is nearly the same, but it precludes machining.
Thus, an engine will only be built once the procrastination stops and the machining begins!