Building a "Turkey," My version of Elmers VR3 #51. (Finished, with video)

[Metal Butcher]

#1 I was a little reluctant to build this model based on a few things I read in Elmer's text. Due to minor concerns a decision was made to build it the actual size as drawn. The time I spent contemplating changes on previos builds will be utilized to produce parts machined to a higher degree of accuracy.

To start off my build scrap pieces of brass and aluminum were marked for rough cutting in the H/V band saw. I generally use low cost scrap that is purchased from scrap yards by the pound. The large brass plate in the picture below will become the "front plate". You can see the evidence of a rough life as an anvil, with its previos owner. It will be resurfaced to become an important part of my project.

#2 Below are the rough cut pieces after trimming off excess material by utilizing the band saw. This will minimize the milling time needed to reach their finished sizes.

I comically named my build "Turkey." Every time I glanced at the drawing of the front plate it reminded me of turkey. It must be a subconscious trigger based on the reality of the up coming holiday.

I can just smell that tasty bird roasting in "Honey's" oven! ;D

-MB

 

[Deanofid]

Looks like an interesting engine, MB. I'm sure you'll have a great build to show us!

Dean

 

[Metal Butcher]

Looks like an interesting engine, MB. I'm sure you'll have a great build to show us!

Dean

Thanks, I certainly hope things go well.

I always wonder if it would be prudent to delay posting until a build is complete and running!.

-MB

 

[zeeprogrammer]

Fantastic. Looking forward to the build.
And like most turkey's this time of year...it will be to a good end!

 

[Metal Butcher]

#3 Today I did a little work on the pieces that were band saw cut yesterday. Four sides of the large brass plate that will become the "front plate" were squared up by end milling. The 1/4" plate was then fly cut down to 3/16" thickness. This surfacing removed almost all the damage on both faces.

#4 The fly cutter did not remove one shallow defect. I should be able to lay out this piece to conceal the minor defect by either the crank disc or the fly wheel. If it were deeper or larger, I would have drilled and reamed it for a tight fitting plug cut .050" longer than the thickness of the plate. Peening the plug tight in the hole and then facing both sides of the plate by fly cutting would conceal the repair.

I enjoyed milling out the opening in the base so much that I decided to mill out a cosmetic opening in the "back plate". It didn't take very long for me to give in to my uncontrollable habit of altering Elmer's plans!
:big:

-MB

 

[Twmaster]

It's OK MB. I too have issues with following instructions....

Sometimes to my detriment!

 

[Metal Butcher]

It's OK MB. I too have issues with following instructions....

Sometimes to my detriment!

Detriment...Been their, done that! ;D

-MB

 

[zeeprogrammer]

It's OK MB. I too have issues with following instructions....

Sometimes to my detriment!

I thought that was called 'learning'...'gaining experience'. (I probably shouldn't say anything...some one's going to ding me for my own thread.) ;D

Thanks for the tip on fixing/repairing the minor defect. I like these kinds of tips.

 

[Metal Butcher]

Zee, glad you liked the info on pluging a hole in scrap to recycle it into a useful part.

I hoped some one would pick up on it and use it someday. It may come in handy to repair a mistake on a time consuming part.

Its fun to point out a well made plug on a model. It adds interest to a project like a well made dovetail does in quality furniture. It also seems to impress people with no knowledge of metal working. "How did you do that?" And you get the Respect of a growing amount of people trying to be politically correct by pretending to be responsible citizens that support recycling. ;D

-MB

 

[Metal Butcher]

#5 I decided to post a picture of the few parts made today. With the up coming holiday shop time will be very limited since "Honey" has a few days off. I be helping out with the preparations and lending a hand with other last minute details.

To add an outside flywheel I felt that the base needed to be raised up a bit. So I milled up a pair runners that blend in with the style of the base. They will add a 1/2" to the base height which will allow an additional 1" in flywheel diameter. In the picture below the previously made original base plate is placed on top to show how the addition will look. The crank disc, crank shaft, and crank pin assembly was a strait forward cut, mill, and drill job. I was very careful when making the 'drill jig' to assure the highest possible precision by milling it to exact dimensions and reaming all of its holes. After a quick dip in 'tool black' I engraved the plan number in case I ever need it in the future.

-MB

 

[Metal Butcher]

#6 The 'front plate' was marked out with scribed lines and intersection points along with the radius for the cylinder pivots, and outer edge radius. The extra line on the outer edge was added since I decided to make the 'front plate' 1/8" larger. This will conceal the sharp protruding front corners I observed on the 'valve plate'.

#7 All the holes were drilled and reamed excluding the six port holes. Those were drilled using the 'drill jig' and 'jig pin'. After removing the jig, and before moving to the next port location, the ports were counter sunk 1/8" x 9/64" deep to accept the 1/8" copper tubing.

#8 To get a nice 1/2" radius on the lower sides of the plate, a 1/2" end mill was carefully advanced up to the scribed lines. The final cut was to split the scribed line by eye. The remaining excess will be trimmed off using the band saw, and belt sanded to the scribed line.

#9 After trimming out the lower corners, the outer radius was trimmed off using the band saw. On this type of curvature its a good idea to use relief cuts to eliminate blade binding. These cuts can be seen in the picture below.

#10 The outer radius was brought up close to the scribed line by using a 1" x 30" belt sander. The plate was secured snugly to a scrap block in the mill's vise using a tight fitting hold down shoulder bolt loctited in place. The plate was tight but could be rotated smoothly with effort. With the mill off, and before I did any cutting, the clearance was checked and adjusted by rotating the work piece, so that there was no contact with the cutting tool. With the mill running and after each full rotation the cutter was advanced only .002". After about 7-to- 8 360 degree cutting rotations the edge was up to the scribed line.

I do NOT recommend this method. The work pieces can be pulled out of your grip and cause injury. It can also lift and tilt taking a larger bite that will as also pull it out of your grip. Rotating the work piece back in a counter clock wise direction or 'climb cut' is increasing these dangerous possibilities. An unsecured piece rotated on a pivot pin will lift and is defiantly an invitation for disaster! I was very careful and fortunately the cutter did not grab the work out of my grip.

A much safer method to consider is the use of a mill mounted rotary table, or lathe mounted face plate.

#11 I finished the piece by sanding it on a glass plate using #220 wet/dry paper. This removed the scribe lines and marks left by the earlier fly cutting. Below is a picture of the front (face) that the cylinders will mount to.

#12 The back side is shown below. This is the side that the 1/8" copper tubes will be soldered to.

Its been said that the oscillating cylinder is forgiving of ports that are not properly located, and off a bit. I really like the use of the drill jigs offered in Elmer's plans. A precision 'drill jig' assures exact port to port alignment based on the cylinders pivot point. The usual result is a successful and smooth running engine.

-MB

 

[gbritnell]

MB, it was good talking with you the other day. It looks like you have a great start to this engine. The brass plate that you were telling me about cleaned up quite nicely. I wish my mill would flycut as well as yours seems to do. I have used burrs in a milling situation but not quite like you have there. Keep up the good work.
gbritnell

 

[Metal Butcher]

Thanks George, it was good talking with you too. You have an open invitation to stop by when ever you find the time.

-MB

 

[Deanofid]

The "turkey tail" looks really nice, MB.

I've used a similar method for rounding corners on pieces, but never on something this large. I agree with you, that a piece this size would be better done on an RT, if it's to be done on the milling machine. You got a great result, in any case.

Dean

 

[Metal Butcher]

Thanks Dean. I'm very pleased with the results.
On small pieces like a connecting rod, a large plate that the piece can be snugly bolted down to and dragged across helps with stability. Shutting down the spindle and pushing a piece back to the starting position, prior to advancing the depth of cut also helps. Work stop pins or adjustable stops help with milling into a corner. The corners are a tough area that grabs the most. Light deliberate cuts that are slow-and-steady are very important.

You probably know all this, but its good to post this type of information. Rather then a dangerous and useless, "Just mill the corners round by pivoting the piece on a tight fitting pin." Someone may try this using just one cut! Or try to advance the cutter with one hand on the hand wheel while pushing the work piece in the direction of a climb cut with the other!

Dwelling on all the dangerous possibilities could keep a sane person up all night.

-MB

 

[Deanofid]

Dwelling on all the dangerous possibilities could keep a sane person up all night.
-MB

You got that right.
If a person ever thought about the danger involved with turning a razor sharp piece of metal at 3000 rpm, with two horsepower behind it, then running another piece of metal into it, on purpose... Well, he might just decide to take up marshmallow eating, instead.

 

[Metal Butcher]

#13 I cut and faced a 1" x 1/4" brass disc that will become the 'valve'. It was bolted face up to mill the two air passages 3/64" deep with a 3/32" center cutting end mill.

#14 The ports on the 'valve plate' shown on the left were done in the same manner.

#15 The ports were de-burred with an Exacto knife. Afterward the 'valve' was bolted to the end a 3/8" mandrel, and chucked into a cordless drill. Then the outer corner was rounded with a file and blended in with 600 grit sand paper. The 'valve plate' was sanded later using a glass plate to remove the obvious file marks seen in the picture below. Two pieces of 3/32" drill rod were cut and the longer one was bent to a 90 degree angle. I added a profiled ball end tip to the finger lever to give it a more 'finished' look.

#16 The air/steam intake tube was made from a 3/4" piece of 3/16" model pipe that was threaded 10-40 on one end. I changed the 'valve' hold down method by tapping the 'valve plate' and reaming a 1/8" hole through the 'valve'. This allows the use of a spring, spring bushing, and hold down screw from the top that is much easier to get at. One of the 1/16" stop pin holes can be seen in the picture below. The two stop pins will be installed using Loc-tite during the 'final assembly'. Leaving them off for now will allow a light lapping should it be found necessary during the 'test assembly'.

#17 My "Turkey" took its first victim today. During a set-up procedure my 3/8" center finder fell out of the spinning chuck and was mangled against a vise jaw. Luckily the part being set-up escaped with out injury. The top of the vise jaw received a minor scar that will be removed with a light 'stoning' using a corundum stick. The center finder was replaced with an identical back-up and the project continued. I think my key-less chuck needs to be replaced since this has happened in the past. There is known previos damage on the chucks jaws that may have been a contributing factor in this mishap. :'(

That's all for now.

-MB

 

[Metal Butcher]

#18 Today I finished up the four frame pieces that were previously milled by drilling and tapping their holes. The cylinders were bored along with drilling the 1/16" ports and tapping the holes for their pivots. The center cylinder (lower left) was bored strait through and will be a built up assembly. The other two cylinders were also bored through and will have cylinder heads similar to the center cylinder (heads not shown) that need to be machined.The the aluminum center piston has a separate rod guide in place on the piston rod and will be pressed into the bottom of the cylinder with Loctite. A t the top of the picture is the flywheel. I changed the location of the drilled holes that are used to balance the engine. I did some calculating to duplicate the amount of material removed, and the six holes were equally spaced and drilled. This was done in an attempt to create a little visual interest that should be seen at lower speeds.

There are still quite a few parts to make, along with a few minor decisions, and a few problems to solve before this project is any where near completion. One of the minor problems is the 1/8" copper tubing that measures .126' to .127" and doesn't fit any of the twelve 1/8" holes in the 'valve plate' or 'front plate'!

It seems to me that this build is taking too long, and should be already finished. :

-MB

 

[Deanofid]

It seems to me that this build is taking too long, and should be already finished. :

-MB

Oh, I dunno, MB. You seem to move right along, to me.
That's a nice looking cache of parts you have there!

Dean

 

[Metal Butcher]

#19 One of the minor issues that this build presented me is the copper tubing used to pipe the air/steam from the 'valve plate' to the ports on the 'front plate'. The tubing I have on hand is a small coil of 1/8" sold at hardware stores and appears to be inconsistent in size, and straightening it out would be quite a chore. Also I have no experience with the cutting and bending that's required. I remembered that this type of material was sold in hobby shops. Below is what was purchased to help solve my piping dilemma. All I need to do is figure out how to cut it "neatly" to proper lengths, and solder it "neatly" in place.

-MB