Stirling Scotch Yoke Engine
By RF Tuper
These are the first set of drawings that I have ever done for someone else to use and it is the first time I have used
this new CAD program (ViaCAD V6 Pro).
I have tried to give the builder what information he or she will need to build the engine but at the same time I did
not want to over load the drawings.
All of the dimensions are in inches unless otherwise noted. You may have to do some simple math to get all of the
dimensions that you may need.
The bearings I used came from McMaster-Carr: You will need 2 (#6384K46 (0.906) O.S., (0.437) I.S. and
(0.312) Wide). You will need 4 (#57155K365 (0.25) O.S. Dia., (0.125) I.S. Dia. and (0.1094) Wide).
The Piston and Power Cyl. must be of very close tolerances. I hone the Power Cyl. until when placing one end
down onto some gasket material and putting the Piston in the other end the air in the Cyl. holds the Piston from
sliding down the Cyl. but when I pick the Cyl. off of the gasket material the Piston drops down the Cyl..
The Disp. Bearing and the Disp. Rod has to be of very close tolerances also. No air leaks.
As for the Base I used a 4” Alu. Channel I just happened to have. As for the hole layout, I would layout the parts
first and then drill the holes. I started with the Cylinder Block first and went from there. That hole is 7” from the
left end and is in the center of the Base.
I hope that this will work for you.
Richard
1.37
Ø 1.37
Ø .5
Ø .75
Ø .906
0.312 Deep
3.
.485
2.
.25
.625
1.169
.375
Ø .177
.312
3.675
2.338
Note: Bearings: McMaster-Carr #6384K46
Project Name:
Stirling Scotch Yoke Engine
Drawn by: R.F. Tuper
Part Name:
Crankshaft Bearing Mount
Date Drawn
08/18/10
Part
A
Unless Otherwise Specified:
Material
Brass
Dimensions in Inches
Tolerances: ±
Comments:
Drawing Not To Scale
ViaCAD V6 Pro. Generated Drawing
Size
Drawing No.
A
0001
8.5 X 11 Sheet 1 of 19
.75
1.065
.68
1.18
1.375
1.375
5.745
0.25 Dia. X 0.25 Wide (4 Times)
2 are Hidden
.25
1.88
Ø .437
Ø .25
.75
Ø1.88
Ø .5
Ø .5
.25
.75
0.375 Dia. X 0.06 Wide
Project Name:
Stirling Scotch Yoke Engine
Drawn by: R.F. Tuper
Part Name:
Crankshaft
Note: Cut a keyway at each end of shaft 0.125 Wide X 0.75 Long.
Date Drawn
Unless Otherwise Specified:
08/19/10
Dimensions in Inches
Part
B
Tolerances: ±
Material
Steel
Comments:
Drawing Not To Scale
ViaCAD V6 Pro. Generated Drawing
Size
Drawing No.
A
0002
8.5 X 11 Sheet 2 of 19
3.877
Ø 1.375
.125 Deep
1.94
.312
Ø 3.877
Ø 3.708
Ø .218
Drill Thru. to Front
A
.149 Dia. Hole Drilled
& Tap in Bottom for #10
to Mount to Base Plate
1.
.089 /Drill & Tap for #4
5 Holes on 1.75 Dia. .375 Deep
.063
.83
2.
.218 Hole Drilled
Thru From Top
1.937
3.5
4.5
.125
3.
.5
Ø 1.568
.0625 Deep
.125 Total from Face
Project Name:
Stirling Scotch Yoke Engine
.063
Ø 1.75
.0625 Deep
Ø .375
Thru. Hole
Drawn by: R.F. Tuper
Part Name:
Cylinder Block
.75
1.25
.125
Ø 1.5
Ø 2.
.25
Date Drawn
Unless Otherwise Specified:
08/20/10
Dimensions in Inches
Part
C
Tolerances: ±
45.°
Material
Alu
Comments:
Drawing Not To Scale
ViaCAD V6 Pro. Generated Drawing
Size
Drawing No.
A
0003
8.5 X 11 Sheet 3 of 19
.125
.25
.625
.75
1.57
See Note
A
Detail A
Ø 1.
Ø .5
Ø 1.
TYP.
.75
.5
5
.5
3.75
4.
.25
.5
Note: Center Line For
Turning Post
Ø .5
.75
.5
B
1.5
.5
Ø .125
Detail B
.25
9.25
B
1.
1.
A
.25
A= Post is a Long Taper, .5 at Base .375 at Top
and 3.437 Long
3.5
Center for .125 Hole is .25 from Top
B= Drill .169 for #8 Cap
Project Name:
Stirling Scotch Yoke Engine
Drawn by: R.F. Tuper
Part Name:
Rocker Support
Date Drawn
Unless Otherwise Specified:
08/23/10
Dimensions in Inches
Part
D
Tolerances: ±
Material
Alu
Comments:
Drawing Not To Scale
ViaCAD V6 Pro. Generated Drawing
Size
Drawing No.
A
0004
8.5 X 11 Sheet 4 of 19
Ø 1.95
Ø .113
Ø 1.5
Ø 1.375
Ø 1.125
The 5- .113 Holes are on 1.75 Dia.
for # 6 Cap
Ø 1.375
.175
.125
2.8
.125
.125
Ø 1.5
.25
Project Name:
Stirling Scotch Yoke Engine
Ø 1.95
Ø 1.375
Drawn by: R.F. Tuper
Part Name:
Power Cyl.
Date Drawn
Unless Otherwise Specified:
08/23/10
Dimensions in Inches
Part
E
Tolerances: ±
Material
Brass
Comments:
Drawing Not To Scale
ViaCAD V6 Pro. Generated Drawing
Size
Drawing No.
A
0005
8.5 X 11 Sheet 5 of 19
Ø 1.125
To Fit Bore
Ø .07
Drill & Tap #2
.25 Deep
Ø 1.065
.25 Deep
Ø .25
.25
.875 Deep
Ø .125
Note: Cut 3 or 4 V-Groves .010 Deep around Piston
Note: Wristpin for piston is .125 Dia. & 1.065 Long / Steel
for Oil Groves about .125 apart
Project Name:
Stirling Scotch Yoke Engine
Drawn by: R.F. Tuper
Part Name:
Power Piston
Date Drawn
Unless Otherwise Specified:
08/23/10
Dimensions in Inches
Part
F
Tolerances: ±
Material
Cast Iron
Comments:
Drawing Not To Scale
ViaCAD V6 Pro. Generated Drawing
Size
Drawing No.
A
0006
8.5 X 11 Sheet 6 of 19
Ø 2.95
Ø 2.436
Ø 1.668
Ø 1.568
Inside Dia.
Ø .113
The 5 Holes are on 2.7 Dia.
for # 6 Cap
.063
.384
.125
.125
2.188
.25
Project Name:
Stirling Scotch Yoke Engine
Drawn by: R.F. Tuper
Part Name:
Displacer Cold End
Date Drawn
Unless Otherwise Specified:
08/23/10
Dimensions in Inches
Part
x
Tolerances: ±
Material
Brass
Comments:
Drawing Not To Scale
ViaCAD V6 Pro. Generated Drawing
Size
Drawing No.
A
0007
8.5 X 11 Sheet 7 of 19
Ø 1.75
Ø 1.448
Inside Dia.
Cold End
.125
Ø 1.75
2.125
Ø 1.568
Ø 1.568
4.625
Ø 1.508
2.375
Hot End
Ø 1.508
End Cap About .30 Thick
Braze or weld End Cap on
Project Name:
Stirling Scotch Yoke Engine
Drawn by: R.F. Tuper
Part Name:
Displacer Cyl.
Date Drawn
Unless Otherwise Specified:
08/23/10
Dimensions in Inches
Part
H
Tolerances: ±
Material
Stainless Steel
Comments:
Drawing Not To Scale
ViaCAD V6 Pro. Generated Drawing
Size
Drawing No.
A
0008
8.5 X 11 Sheet 8 of 19
Ø 1.388
Ø 1.388
Outside Dia.
Ø 1.328
Inside Dia.
Ø .125
Ø .098
Drill & Tap 3mm
Displacer End Cap
Cold End
Displacer
Hot End
.063
.126
Ø 1.328
.063
2.875
A = Wall .03 Thick TYP.
Displacer End Cap
Cold End
B = End .063 Thick
Displacer
Project Name:
Stirling Scotch Yoke Engine
Drawn by: R.F. Tuper
Part Name:
Displacer and End Cap
Date Drawn
Unless Otherwise Specified:
08/24/10
Dimensions in Inches
Part
I
Tolerances: ±
Material
Alu
Comments:
Drawing Not To Scale
ViaCAD V6 Pro. Generated Drawing
Size
Drawing No.
A
0009
8.5 X 11 Sheet 9 of 19
Ø .375
Ø .125
2.
Note: Put a small Chamfer on Crankshaft End
Project Name:
Stirlind Scotch Yoke Engine
Drawn by: R.F. Tuper
Part Name:
Disp. Bearing
Date Drawn
Unless Otherwise Specified:
08/24/10
Dimensions in Inches
Part
J
Tolerances: ±
Material
Brass
Comments:
Drawing Not To Scale
ViaCAD V6 Pro. Generated Drawing
Size
Drawing No.
A
0010
8.5 X 11 Sheet 10 of 19
.125
.25
Ø .5
.625
Ø .125
.25
1
.75
.5
Ø .25
.5
Ø .125
Detail C
Detail E
.25
E
C
A
A = 3mm Threads
.25 Long
B
7.26
B = .125 Dia.
.125
C = 3mm Threads
.125 Long
Project Name:
Stirling Scotch Yoke Engine
Drawn by: R.F. Tuper
Part Name:
Disp. Rod and Yoke
Date Drawn
Unless Otherwise Specified:
08/25/10
Dimensions in Inches
Part
K
Tolerances: ±
C
Material
Brass
Comments:
Drawing Not To Scale
ViaCAD V6 Pro. Generated Drawing
Size
Drawing No.
A
0011
8.5 X 11 Sheet 11 of 19
Ø .25
See Note:
.25
1.75
.5
Ø .25
2.25
F
3.
6.
Note: Bearing = McMaster-Carr #57155K365
.25
.75
.125
Ø .5
.5
.25
G
Ø .125
5.
.625
6.5
Detail F
Project Name:
Stirling Scotch Yoke Engine
Drawn by: R.F. Tuper
Part Name:
Rocker Arm
Date Drawn
Unless Otherwise Specified:
08/25/10
Dimensions in Inches
Part
L
Tolerances: ±
Detail G
Material
Brass
Comments:
Drawing Not To Scale
ViaCAD V6 Pro. Generated Drawing
Size
Drawing No.
A
0012
8.5 X 11 Sheet 12 of 19
Ø .25
See Note:
.25
Ø .5
.125
.063
H
H
Ø .125
Ø .25
Section H-H
2.79
3.343
Note: Bearings = McMaster-Carr # 57155K365
.25
3.843
Project Name:
Stirling Scotch Yoke Engine
Drawn by: R.F. Tuper
Part Name:
Power Conn. Rod
Date Drawn
Unless Otherwise Specified:
08/25/10
Dimensions in Inches
Part
M
Tolerances: ±
Material
Alu
Comments:
Drawing Not To Scale
ViaCAD V6 Pro. Generated Drawing
Size
Drawing No.
A
0013
8.5 X 11 Sheet 13 of 19
5.5 for Rocker/Power Piston
3 for Displacer Piston
.125
.0625
Ø .25
See Note:
.312
I
.75
Section I-I
I
.25
Ø .125
.625
Note: Bearing = McMaster-Carr # 57155K365
.125
.25
Ø .25
Ø .07
Drill & Tap
for #2 Cap
Ø .25
.125
Ø .25
.375
Project Name:
Stirling Scotch Yoke Engine
Drawn by: R.F. Tuper
Part Name:
Conn. Rods/Power and Disp.
Date Drawn
Unless Otherwise Specified:
08/25/10
Dimensions in Inches
Part
N
Tolerances: ±
Material
Alu
Comments:
Drawing Not To Scale
ViaCAD V6 Pro. Generated Drawing
Size
Drawing No.
A
0014
8.5 X 11 Sheet 14 of 19
.75
.125
.5
.125
.125
Ø.098
See Note:
Ø .118
3mm Threads
.25
Ø .125
Note: Drill & Tap for 3mm
Will need 4 Bolts & Nuts
Project Name:
Stirling Scotch Yoke Engine
Drawn by: R.F. Tuper
Part Name:
Nut and Bolt
Date Drawn
Unless Otherwise Specified:
08/26/10
Dimensions in Inches
Part
O
Tolerances: ±
Material
Brass
Comments:
Drawing Not To Scale
ViaCAD V6 Pro. Generated Drawing
Size
Drawing No.
A
0015
8.5 X 11 Sheet 15 of 19
Ø 2.
Ø .437
Ø .136
Ø 1.
See Note 1:
Note 1: Drill & Tap 6 Holes for #8 Cap on 1.5 Dia.
Ø .106
See Note 2:
.575
.95
.375
Note 2: Drill & Tap for #6 set
Project Name:
Stirling Scotch Yoke Engine
Drawn by: R.F. Tuper
Part Name:
Hub
Date Drawn
Unless Otherwise Specified:
08/26/10
Dimensions in Inches
Part
P
Tolerances: ±
Material
Alu
Comments:
Drawing Not To Scale
ViaCAD V6 Pro. Generated Drawing
Size
Drawing No.
A
0016
8.5 X 11 Sheet 16 of 19
Ø 6.375
Ø 5.375
Ø 1.
Ø .173
See Note:
Ø .5
Ø 5.125
Ø .5
20.°
Note: 6 Holes on 1.5 Dia. from Center of Wheel
A
40.°
.25
10.°
60.°
B
30.°
.75
40.°
.25
.25
A = Center of Outside Holes are 2.31 from Center of Wheel
B = Center of Inside Holes are 1.31 From Center of Wheel
Project Name:
Stirling Scotch Yoke Engine
Drawn by: R.F. Tuper
Part Name:
Fly Wheel
Date Drawn
Unless Otherwise Specified:
08/26/10
Dimensions in Inches
Part
Q
Tolerances: ±
Material
Steel
Comments:
Drawing Not To Scale
ViaCAD V6 Pro. Generated Drawing
Size
Drawing No.
A
0017
8.5 X 11 Sheet 17 of 19
Ø 3.5
A
See Note:
Ø 3.
Ø 3.
Ø .5
Ø .375
Ø .625
1.125
Ø .173
Ø 2.875
A = Drill #60 Hole Thru. Fill Cap
Note: Fill Pipe is .25 High Brass and JB Welded to Cover
Ø .5
.063
2.87
.063
.556
.25
.688
.938
.078
.236
.25
J
.25
.361 .477
B = Groove for a O Ring
B
.075
Detail J
Project Name:
Stirling Scotch Yoke Engine
Drawn by: R.F. Tuper
Part Name:
Heater
Date Drawn
Unless Otherwise Specified:
08/27/10
Dimensions in Inches
Part
U
Tolerances: ±
Material
Alu
Comments:
Drawing Not To Scale
ViaCAD V6 Pro. Generated Drawing
Size
Drawing No.
A
0018
8.5 X 11 Sheet 18 of 19
15.
1.5
.875
1.
10.°
10.°
Note: Hole layout may be different from your layout. It may be best to lay your parts out first then drill the Holes.
9.75
7.
1.75
Ø .196
Ø .136
Ø .136
Ø .136
Drill & Tap 6 Holes # 8
Ø .089
3.563
Drill & Tap # 4
Ø .089
3.5
Ø .136
Ø .136
2.
3.75
Ø .136
4.
.25
.5
.437
12.125
13.971
15.
Project Name:
Stirling Scotch Yoke Engine
Drawn by: R.F. Tuper
Part Name:
Base
Date Drawn
Unless Otherwise Specified:
08/27/10
Dimensions in Inches
Part
R
Tolerances: ±
Material
Alu
Comments:
Drawing Not To Scale
ViaCAD V6 Pro. Generated Drawing
Size
Drawing No.
A
0019
8.5 X 11 Sheet 19 of 19