Difference between revisions of "Clamps"

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(Bar clamps)
(Bar clamps)
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How do you check clamps for rigidity?  How far can you turn the screw after the clamping surfaces meet?  My 4" cast clamps with coarse square threads are tight after about 10 to 15 degrees.  My lighter duty ductile iron 3" medium deep reach clamps with finer triangular threads are almost tight after 720 degrees.  Big difference.  Which is more rigid?  For the deep reach C clamps, you might want to go with higher quality drop forged construction, and stick with less costly cast clamps for normal reach.  But don't get me wrong.  The smaller/lighter clamps are very useful.  They just don't clamp as hard.
 
How do you check clamps for rigidity?  How far can you turn the screw after the clamping surfaces meet?  My 4" cast clamps with coarse square threads are tight after about 10 to 15 degrees.  My lighter duty ductile iron 3" medium deep reach clamps with finer triangular threads are almost tight after 720 degrees.  Big difference.  Which is more rigid?  For the deep reach C clamps, you might want to go with higher quality drop forged construction, and stick with less costly cast clamps for normal reach.  But don't get me wrong.  The smaller/lighter clamps are very useful.  They just don't clamp as hard.
  
==Toolmakers Parallel Clamps==  These look like miniature Jorgensen woodworking clamps, but they work differently.  You back off the rear screw, tighten with the middle one and then finish with leverage by tightening the rear screw.  These come as small as just over and inch and up to about four inches.  These are incredibly useful for holding small stuff, clamping two or three parts together for drilling, etc.  A pair of top of the line Starrett clamps with 1.25 inch max jaw opening is $45.  But you can get lower end ones that work fine for as little as $5 for 1.25" up to $23 for 4.5"
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==Toolmakers Parallel Clamps==   
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These look like miniature Jorgensen woodworking clamps, but they work differently.  You back off the rear screw, tighten with the middle one and then finish with leverage by tightening the rear screw.  These come as small as just over and inch and up to about four inches.  These are incredibly useful for holding small stuff, clamping two or three parts together for drilling, etc.  A pair of top of the line Starrett clamps with 1.25 inch max jaw opening is $45.  But you can get lower end ones that work fine for as little as $5 for 1.25" up to $23 for 4.5"
  
 
[[file:tool-makers-clamp.png]][[file:tool-makers-clamp-set.png]]
 
[[file:tool-makers-clamp.png]][[file:tool-makers-clamp-set.png]]

Revision as of 02:03, 10 November 2011

-Good clamps to have on hand-


C Clamps

There is a wide variety of sizes and quality. Here are some 4 inch clamps from Home Depot. The blue one is made by Irwin, at $8. The clamping force is not specified, and it just says it is made of "steel". The black one next to it is the same size in drop forged steel made by Jorgensen, and is $20. The difference is the material and the clamping capacity. The Jorgensen clamps at 6200 pounds; the Irwin does not specify clamping force . The third one, also made by Jorgensen but cast, not drop forged, clamps at 2400 pounds, has square threads, and goes for $13. For our purposes, drop forged clamps are probably overkill, but I like the cheaper Jorgensen with the square threads. Square threads make a significant difference in how much effort you need to put into tightening the clamp.

Irwin-c-clamp.pngC-clamp3.pngSquare-thead-c-clamp.png

Deep reach C clamps

These let you clamp to benches, drill press tables, the band saw table, etc, with a lot of distance between the back of the clamp and the clamping surfaces. Careful on this, because they need to be very strong to support this distance and still clamp tight. Three different depths shown below. The deeper, the less rigid, so take some measurements on the machines before deciding.

Deep-clamp.png C-clamp1.pngC-clamp2.png

Bar clamps

Bar clamps can open up very wide, but are not generally as strong as a good C clamp. they are, however, a very good clamp to have around because of the ability to clamp over a large distance. Two bar clamps are shown here, one with a deep reach.

Deep-bar-clamp.jpgBar-clamp.jpg

How do you check clamps for rigidity? How far can you turn the screw after the clamping surfaces meet? My 4" cast clamps with coarse square threads are tight after about 10 to 15 degrees. My lighter duty ductile iron 3" medium deep reach clamps with finer triangular threads are almost tight after 720 degrees. Big difference. Which is more rigid? For the deep reach C clamps, you might want to go with higher quality drop forged construction, and stick with less costly cast clamps for normal reach. But don't get me wrong. The smaller/lighter clamps are very useful. They just don't clamp as hard.

Toolmakers Parallel Clamps

These look like miniature Jorgensen woodworking clamps, but they work differently. You back off the rear screw, tighten with the middle one and then finish with leverage by tightening the rear screw. These come as small as just over and inch and up to about four inches. These are incredibly useful for holding small stuff, clamping two or three parts together for drilling, etc. A pair of top of the line Starrett clamps with 1.25 inch max jaw opening is $45. But you can get lower end ones that work fine for as little as $5 for 1.25" up to $23 for 4.5"

Tool-makers-clamp.pngTool-makers-clamp-set.png