Elmer's #50 Educational Model

[Gerry Sweetland]

Hi all,
Have not posted in a while, I introduced myself back in March of 2009 when I bought a RF 30/31 clone
asked for some advice on that machine. Since then I kind of moved the home machining thing to the back burner and just brought it forward this past winter.
I have been working on Elmer's #50, the Educational Model for a little bit this past winter using the
RF clone.
Towards the end of spring I purchased a Tormach PCNC770 and I have been learning CNC between summer yard projects and “honey-do” lists.
Now that fall is here I am devoting more time to the shop and Elmer's #50.
I have attached a photo showing the few parts I have made so far. Everything except the flywheel I made on the RF clone, the flywheel was made on the 770. I don't know if you can tell in the photo but the center hole and the boss it is in as well as the inside perimeter of the soon to be outer ring is all off center, must of slipped in the hold clamps or I got my 0X and 0Y wrong when I flipped the part over to machine the other side. Right now I'm trying to decide on if I want to salvage the part by changing the diameters of the hole, boss and inner edge of the wheel, probably should just start over.
No problem, I am enjoying the challenge and the puzzle of this CNC thing.
I would like to maybe do a Work in Progress thread on Elmer's #50 here on the forum but I have a hard time putting my thoughts down and organizing the posts with photos and descriptions, especially reading thru some of the amazing Work in Progress posts that all you fellas do, and the incredible things that you guys create on your machines I guess it gave me inspiration to at least try.
Thanks for reading,
Gerry

 

[maverick]

Gerry,
That's a good start on the flywheel, and shouldn't take much work to salvage it. A good way
to approach a part like this is with a sacrificial plate clamped to the table. Drill 2 dowel pin holes
on the centerline of the part blank and use them to locate the part when you turn it over to machine
the second side. This setup makes more sense when you do multiple parts but it is very accurate.

Regards,
Mike

 

[George_Race]

Hi there:
I am a fairly new builder also. Have spent the past couple of years building a small CNC and learning all the stuff that goes with making metal parts.

What works for me when making a flywheel, and I do the majority of the work on the CNC, is that I start by "milling" a .125 hole dead center in the work piece which will eventually be where it mounts to the shaft. Then when i turn the piece over to mill the other side, I use a piece of .125 stock in place of the cutting bit to again find the X and Y center point of the work piece. I then zero out the X and Y axis on the DRO and work off of those locations for the rest of the work. That more or less guarantees that both sides will be working off the same center point location

Has really worked well for me so far.
George

 

[Gerry Sweetland]

Thanks for the suggestions on how to locate the blank for the flywheel fellas.
I was thinking about doing it over and locating from center as George mentions but I never thought of making the center of the model my X and Y 0 and using a pc. of stock the same size as the center hole to re-locate 0. Great idea!
And Mike, I do use a pc. of aluminum attached by T-nuts and socket head cap screws in counter-bores in the surface of the table. Then position some small socket head cap screws threaded above the surface, two along X and one along y to form sort of a right angle fence to park the blank against w/ X and Y 0 in the top left corner of the blank. But I think after looking at it better my blank was not square so when I flipped the part over it created an offset where as if I had done how you suggested that would not have been a problem. I need to order some dowel pins, seem they would come in handy to have in the tool box for setups.
I hope to try to salvage the part or start over using methods I just learned from you guys and I will post back here on my results.
Thanks again,
Gerry

 

[maverick]

As you probably noticed, this forum is a great place to find answers. I've been machining parts since the
70's and still learn alot from the members here. One of my first jobs was in a shop with about a dozen
grouchy old guys (about the age I am now) that didn't consider their days work done until they taught the
new kid something. Sometimes this board feels like a time machine. Looking forward to your report.

Regards,
Mike

 

[Gerry Sweetland]

Hi again,
just a little bit of progress. I completed the flywheel using the center as X0, Y0 and flipping and using a .5" tool to relocate center.
I tried to get photo of the machine making the cut but there was coolant splashing all over the place

Here is the part after the first few operations

I forgot to take pictures of the final operations where I cut the perimeter and chamfered the outside edges.
I got so caught up in running this part that didn't even think about the camera. I'll try to do better in the future.

I haven't run my lathe in a while so I went to doing some work over there.
I had to make brass bushings for the different axles on the flywheel and cam/ con rod.

I chucked a pc. of .5" Ø brass in the three jaw and faced it off

I then turned down the OD for the bushing. I used the CNC to make some brackets for mounting some scales I had laying around. This made it so much easier and more precise for me to get the diameters and lengths to print then using the mag base, dial indicator I was turning with before.

Here I have finished the bore for the ID on one of two larger bushings, I used a center drill first then a 3/16" Ø drill then this 1/4" Ø end mill to finish. I need to invest in some chucking reamers I think.

Here I am setting up to create the shoulder and part the pc. off. I used a small pc. of 12 ga. wire in the tail stock drill chuck to contain the pc from flying off to parts unknown around the lathe

Here is the bushing after the parting operation.

Here is a photo of the finished flywheel and bushings.

I need to work on the connecting rod next in the mill while I still have the aluminum plate bolted to the bed.
Here is a screen cap from the cam software I use (SprutCam) showing the con rod with the "stock box" around the part.

And here is the stock set up in the mill ready to be machined

It's late so I will end here. Hopefully tomorrow I'll get the con rod made and I can get the vice back in the mill to start working on some of the other parts.
Please forgive me for the way this build story is starting out, I'm new to machining and new to posting the build but I hope I get better at both things.
Thanks for reading,
Gerry

 

[GailInNM]

I'm new to machining and new to posting the build but I hope I get better at both things.

Gerry,
You are doing fine on all accounts. And since I had not done so before -- Welcome to HMEM.
wEc1
Gail in NM

 

[ShedBoy]

Nice start. I like the look of this engine especialy the valve mechanism. I will be watching along.
Brock

 

[Gerry Sweetland]

Thank you Gail and Brock.
Gerry

 

[Gerry Sweetland]

Just a small update,
The con rod...
I had previously tried running this part using a much smaller pc. of aluminum and separate machining operations moving hold downs, re-locating 0, etc. and that did not work out. The part slipped and did not come out to print.
So plan B was taking the con rod from a pc. of aluminum that is .25" thick by 1" wide by ~10" long (the finished pc measures .125" thick by ~.4" at the widest point by 8.2" long) . My plan was to run the hole machining operations then the outside profile in the pc. of .25" thick aluminum stock at .187" deep then flip the part over and surface the aluminum stock down to release the con rod from the blank.
That did not go well either
Here is the first side.

And here is the second side

As you can see further up the thread here I was just using two clamps, one on either end.
Things went well until I was almost done with the second side, the part broke free and rotated on the clamp then was pulled up by the cutter.
OK, on to plan C :big:
I am using a pc. of stock that allows me to clamp it down in more locations (one on each end and a couple in the middle) and leave some tabs that I will file off by hand.

I'll show the results on the next update.
Thanks for reading,
Gerry

 

[Gerry Sweetland]

Hi,
I ran the con rod this morning. Here is a photo after the hole machining operations.

The .062 Ø hole on the right was done with a drill chuck and drill in the spindle. The two larger holes were done as a pocketing operation with a .125" Ø end mill so I can make the holes at a somewhat custom size to press fit the brass bushings into at assembly.

Here is a photo of the milling operation that is cutting out the profile.

And here is a photo of the finished pc still in the mill. Sorry for the dark photo, my camera eats batteries like crazy.

I used a hack saw blade to take the con rod away from the scrap and then clamped the con rod in the vise and filed most of the spur away. I then mounted the file in the vise whilst holding the con rod as flat as possible to finish the edge. I also used 240 grit sand paper to finish the edge and the face of the part.

Here it is finished.

Now I clean up the mill and mount the vice and get on with some of the small fiddly bits such as the cross-head, cam, crank and assorted shafts and stuff.
I modeled the engine in SolidWorks, here is a screen cap of the whole assembly (almost, still need to model and insert a few items in the assembly)

Thanks for reading.
Gerry

 

[Gerry Sweetland]

Hi again,
My old Canon Power Shot camera finally died so I had to save up and by a new camera. Now that I have a working camera I did a little bit more on Elmer's #50. The first half or so of the photos that follow are still on the old Canon, the last few are on the new Nikon
I'll start with the cam.
I started with a 2.75" X .75" Ø HRS bar.
Mounted it in my lathe, faced it off and used a #1 center drill to locate a center point.

I then mounted it in the vice on the mill using a V-Block to help clamp it.

Here is a shot of it being machined.

And here is shot of the cam after machining.

I then mounted the HRS bar with the machined end in my lathe again and parted it off the blank.

I then mounted the cam back in the lathe with the rough faced off end facing out. I touched the turning tool of the face of the three jaw and zeroed out the DRO. I then moved the compound rest out to the correct height or length of the cam and zeroed out the DRO again. Now I know where to stop when I start at the extended face of the cam and work my way back in.
Here is a shot of the set up before I began turning.

Here are a couple of shots of the finished cam.

Next I need to machine the brass cross head.
I started with a pc. of brass that was the correct finished size (.25" X .5" X .5") that I machined from a .5" X .75" bar.

I mounted it in the vice and ran the deep groove on the end of the cross head. I made some aluminum vice jaws so I could get a deeper bite on the little pc. of brace and not worry about machining into the steel jaws.

I then did the first groove on the edge of the part.

As well as the second groove on the opposite edge and the hole for the pin that holds the con rod to the cross head. Notice that I went a little deep on the spot drill, you can see it on the top edge's of the groove

I then had to drill and tap a hole for the piston rod to thread in to on the opposite side of the first groove.

Here is shot of the finished part.

Next I have to machine the crank. My plan was to machine the part from one side than rough cut the blank and turn it over and machine down to finished thickness. Here is how I proceeded...

I started with a pc. of 1.25" X 2" X 1" HRS bar with some references scribed to help locate it on the mill and in the Cam program.

I then mounted it in the vice on the mill and ran the profile. I modeled the part a little thicker (.313") than what it finishes at (.25") so that when I was done with the first side I would plenty of material to flip over and machine down to finished thickness.

Here is the part after the profile operation.

And after the two holes. I machined the .25" Ø hole and drilled the .125" Ø hole.

I pulled the part out of the machine vice and clamped it in the bench vice and used a porta-band saw to slice the extra thick crank off the steel block.

I then replaced the steel jaws in the machine vice with the aluminum jaws so I could run a pocketing program that was the same profile as the finished crank and slightly smaller in the Y + and - directions so I could clamp the crank in the vice to face down to size.

I then opened the vice a bit to clamp the crank in the pocket.

I then machined the crank down to finished size.

Here is the crank almost finished, I realized while writing this that I still need to machine a tapped hole in the edge on the end with the .25" Ø hole for the set screw to hold it on the crank shaft.

That's it for now. I don't have too much more to go, drill and tap a few holes in some of the parts, need to make the steel cam drive rod assembly as well as the cam shaft. These parts as well as some of the brass parts need to be silver soldered. That is something I have no idea on how to do or what I require so I need to do some searching here on the forum and see what I can learn.

Thanks for reading,
Gerry

 

[ShedBoy]

Great pics there Gerry, really enjoying this thread. When silver soldering little brass parts practice on similar size bits first, nothing worse than melting made parts. Keep up the good work.
Brock

 

[Gerry Sweetland]

Thanks Brock.
Thanks for the advice on silver solder too.
Gerry

 

[Shopguy]

Gerry
Coming along real nice. BTW when silver soldering you can't get the parts too clean before fluxing and soldering.
Ernie J

 

[Gerry Sweetland]

Thanks Ernie,
Thanks also for tip on getting the parts clean, much appreciated.
Gerry

 

[Gerry Sweetland]

Hi all,
Another update on this build.
I need to make the parts for the brass valve rod assembly then solder (or should I say braze?) them together.

Here is a photo of the stock mounted in a V-Block in the mill vice being milled

And here is photo of part being drilled for the .093" Ø brass valve rod.

The design calls for two of these parts so I flipped the stock over and ran the two operations again.

I cut the brass rod to length, here is a photo of the three parts needed for the assembly.

I first soldered the end pc. to the rod and the design calls for the flats on the each pc. to match and to be 2.375" apart.
So in order to solder the second pc. on to the rod I cut a pc. of 16 ga steel to length and clamped the whole assembly in my bench vice with the addition of a small C-clamp.

And the finished assembly.

To prepare the parts I cleaned the mating surfaces the best I could with emery cloth and used flux from the kit I had purchased (Harris Stay-Bright).
I then cut the solder into tiny pellets and placed 3 or 4 pellets of solder around the intersection of the parts to be soldered.
I thought I had a photo of the assembly showing this but I must of deleted it, all I have is the photo of the little pellets of solder.

I needed to solder some steel parts too.

This also went well. I was a little worried about the assembly in the first photo above. I had soldered the short pc. to the little square block after soldering the long pc. Luckily the long pc. did not become loose and drop out. This is the first time I have soldered real finished parts rather than practice parts together. To my surprise it went pretty good!

At this point I did not have too much left to do. Drill and tap the crank and the cam to hold them on their shafts and some sanding and clean up.

Here are a couple of photos of the finished engine.

Unfortunately when I apply air it does not run. At first the whole mechanism did not run very smoothly when rotating the flywheel by hand so I started removing connections one at a time to see if I could tell where the "hitch in it's get-a-long" was. I found a couple of parts that needed to be filed or tweaked and got the whole thing to run pretty freely by hand. I played around with the timing and I think I got that pretty close. I think where my problem is, is the valve block. The bore for the valve rod assembly is supposed to be a close fit and smooth.
That's the hole in the end of the square alum. part you see in the photo below. There is a lot of air escaping from both ends of the valve block where the valve rod goes thru.

I just drilled it with a finished size twist drill. I should of drilled it undersize and ream it like I did the cylinder but I did not have any reamers (I had borrowed the one for the cylinder from the tool room at work when I still was working). I have a set of over under chucking reamers coming from Enco this Wed. so I think I will make the valve block over again, maybe the valve rod as well.

If I get it to run I will post over at the finished projects forum but frankly, I'm looking forward to another model and putting #50 on the back burner.
I like the Grasshopper #37 so I started modeling it in SolidWorks.

I have learned quite a few things, #50 has taught me a lot, I need to be more precise. That even a big 3 axis CNC does not necessarily help you there.
I am constantly amazed at looking at the projects all you fellas make here and how well you set up and think things thru and do such amazing things with your manual mills.
I'm a bit embarrassed and humbled at showing what I have done. I just hope that I can keep learning and get better at this amazing hobby.
Thanks for reading,
Gerry

 

[lazylathe]

Awesome work Gerry!!! :bow:

I am sure you will get it up and running in no time!

Andrew

 

[rleete]

Sliding spool valves have to fit nearly perfectly to not leak. Ream the bore, and remake the spool valve to fit. You shouldn't have to remake the valve block, just smoothe out the bore.

Timing is a pain to get right, but play with it a bit. Even with a badly leaking valve, you should be able to get it to run, just not well. You're probably 180 degrees out of phase, or trying to get it to run in the opposite direction. I know I fussed with my first one for days until it dawned on me what I was doing wrong. From there it's just tweaking.

Fine looking engine, hope to see it running soon.

 

[kustomkb]

Real nice work there Gerry!

I really like the stretched out look of this engine.