Cheap Dogs

[Delais]

M 20 Bolts

 

[Qwas]

Just a word of caution for anyone wanting to use these bolts for precision. First, the diameter is 19.75 mm which is a very sloppy fit on the MFT/3 holes of 20.1 mm. The hex head should be around 30 m between flats but this can vary on the same bolt and my pair vary from 29.88 to 30.05. Also there is no promise with bolts that the head is concentric with the body of the bolt. My pair is off center by .5 mm. They could still be used for precision work by finding flats that match up on a pair of bolts, marking them, and then only use those flats.

 

[jonny round boy]

Even cheaper dogs - 20mm electrical conduit. [wink]

[big grin]

 

[Mr Heavy]

Socket head screws. Tops are 30mm and I've had no problem with concentricity.

I find that from my suppliers at least, the black phosphate finish screws are a tighter fit -  with absolutely no discernible wobble - than the bright finish offerings. YMMV.

 

[Northernlight]

On my welding table with a laser cut holepattern I'm using m20 hex head bolts for alignment. These are round and I've found them to be very precise.