Telescoping Pipe and Tube

Please refer to Pipe, Tube and Conduit for more information.

Tube, pipe, EMT and bolt manufacturers haven't gotten together and helped us much when it comes to telescoping their products inside one another. This is a survey of only part of what is available, but covers the more readily obtainable materials.

OD=Out Diameter
ID=Inner Diameter

STEEL, ALUMINUM and PVC PIPE always have the same OD regardless of wall thickness/schedule.
PIPE has a larger OD than its RATED SIZE.
PIPE SCHEDULE /Skd. refers to wall thickness (5,10,20,40,80 and 160)
PVC pipe is also rated in pressure.
TUBE always has the same OD regardless of wall thickness. ID= OD minus 2 times the wall thickness.
Most Square Perforated Square Steel Tubing telescopes and come in many sizes.
Type Measurement (All units in inches)
Rated Pipe or Tube Size 1/4 3/8 1/2 3/4 1 1 1/4 1 1/2 2 3
All Pipe OD .54 .675 .840 1.050 1.315 1.660 1.900 2.375 3.5
 
Water Pipe Skd 40 ID .364 .493 .622 .824 1.049 1.380 1.610 2.067 2.469
Water Pipe Skd 80 ID .302 .423 .546 .742 .957 1.278 1.5 1.939  
 
PVC Pipe 125# ID       .935   1.525      
PVC Pipe 200# ID       .915 1.175        
PVC Pipe Skd 40 ID .354 .483 .602 .804 1.029   1.59 2.047 3.042
PVC Pipe Skd 80 ID .288 .407 .546 .724 .935 1.256 1.476 1.913 2.864


PVC Nipples Skd 80 ID
(Nipples are Skd. 80) 		.302 .423 .55 .74 .957 1.278 1.5 1.939 2.90
PVC Coupling OD (Approx.)     1.075 1.275 1.605 1.970 2.25 2.735  
 
Rated EMT Elec. Conduit Size     1/2 3/4 1 1 1/4 1 1/2 2  
EMT Elec. Conduit OD     .71 .92 1.16 1.51 1.74 2.2  
EMT Elec. Conduit ID     .615 .824 1.050        
 
Rated Alum Tube Size 1/4 3/8 1/2 3/4 1 1 1/4 1 1/2 2  
Alum Tube OD .25 .375 .5 .75 1.0 1.25 1.5 2  
Alum.Tube .035Wall ID .18 3.05 .43 .68 .93 1.18 1.43 1.93  
Alum.Tube .049Wall ID .15 .277 .402 .652 .902 1.152 1.402 1.902  
Alum.Tube .065Wall ID .12 .245 .37 .62 .87 1.12 1.37 1.87  
 
Rated Copper Water Pipe Size 1/4 3/8 1/2 5/8 3/4 1 1 1/4 1 1/2  
Copper Water Pipe OD .375 .5 .625 .75 .875 1.125 1.375 1.625  
Copper Water Pipe "L" ID .315 .44 .545 .666 .785 1.025 1.265 1.505  
Copper Water Pipe "K"ID .305 .402 .527 .652 .745 .995 1.245 1.481  
Expensive but could make collars. Turns nice in a lathe. Will not gall aluminum
 
Rated Galvanized Fence Tubing Size (Cheap) 1 3/8 1 5/8 1 7/8 2 3/4          
Equivalent Pipe Size 1.0 1.25 1.5 2.0          
Fence Tubing OD (Approx..) 1.375 1.625 1.875 2.375          
Rough ID (Approx.) 1.237 1.487 1.737 2.237          
 
Bolt Size 10/32 1/4 5/16 3/8 1/2 9/16 5/8 3/4 7/8      1
Bolt Actual OD .185 .244 .307 .369 .495   .620 .745 .87      .995
Average hardware store bolts. Not precision bolts which are exactly rated size. 5/1000 can be a loose fit in a short fitting part.Coupling nuts are usually smaller OD than regular nuts.


NOTES
All EMT sizes are telescoping, but a bit sloppy. Two EMT compression couplings can be joined to make an adjustable telescoping fitting. A lathe is helpful, but a sander, a file and some work will make them join together. If you put shrink tube on the end of the smaller tube, the fit can be very good. Layers of tape can work also but can jam if it unravels. If you find a ready made coupling that telescopes, please let me know. I will share it.

PVC which is made with many different ID's, makes many possibilities to make sleeves.

1/2" PVC Skd. 80 (Nipples) With a lengthwise saw cut will slip into 3/4 EMT and fairly tight fit for a 1/2" bolt or threaded rod.

Paddle wood bits can be sanded down to EMT and pipe sizes for boring wood and plastic. Make sure they taper smaller away from the cutting tip like they are originally. You can spin them in an electric drill against a belt sander to make them smaller. Keep drilling test holes before you take off too much metal. NOTES
All EMT sizes are telescoping, but a bit sloppy. Two EMT compression couplings can be joined to make an adjustable telescoping fitting. A lathe is helpful, but a sander, a file and some work will make them join together. If you put shrink tube on the end of the smaller tube, the fit can be very good. Layers of tape can work also but can jam if it unravels. If you find a ready made coupling that telescopes, please let me know. I will share it.

PVC which is made with many different ID's, make possible many possibilities to make sleeves.

1/2" PVC Sked. 80 (Nipples) With a lengthwise saw cut will slip into 3/4 EMT and fairly tight fit for a 1/2" bolt or threaded rod.

Paddle wood bits can be sanded down to EMT and pipe sizes for boring wood and plastic. Make sure they taper smaller away from the cutting tip like they are originally. You can spin them in an electric drill against a belt sander to make them smaller. Keep drilling test holes before you take off too much metal. See Making Homemade Grip Equipment

Paddle bits to reduce: 3/4" for 1/2" EMT, 15/16" for 3/4" EMT, 1-1/2" for 1" EMT

3/8"-16 nuts can be pressed into 1/2" EMT and 1/2"-13 nuts can be pressed into 3/4"EMT. Space the two nuts apart for more stability. Hammer over end of EMT to retain nut at end of EMT. If you use left-hand threads you can make your own turnbuckles if you braze the nuts in place. Don't breathe the zinc fumes from the galvanized EMT or water pipe when welding or brazing.

Paddle bits to reduce: 3/4" for 1/2" EMT, 15/16" for 3/4" EMT, 1-1/2" for 1" EMT

© Copyright 1999-2004 Ron Dexter. All Rights Reserved.