[rkremser]

I"m trying to find blind hole clamps that are between 1/8" and 3/8". Mcmaster has smaller ones but not the larger size i'm looking for (mcmaster part 5099a) What are these actually called and any ideas of where to find another source?

[neilw20]

Aircraft maintenance / builders use all sorts of blind clamps.
They call them sheet holders.
Try clecos
http://www.yardstore.com/browse.cfm/2,427.html
I am guessing that's what you need.

[rkremser]

will these "clecos" clamps work for blind holes or will they only grab two thin layers? I am trying to hold a piece of sheet metal to a blind hole drilled into a block of material. This would just be temporary and would have to be easily removed later. Any other options for something along these lines?

[JerryFlyGuy]

Cleco's are not used in blind holes but rather 'thru' holes in two pc's of sheet.. work great in that application but I've never seen them used in a blind hole.

Not sure what to recommend for locking into a blind hole. I'm sure some old machinist will jump in and give you the old school way of doing it.. :-)

[neilw20]

The cleco work by having to blobby end that wedge when springloaded up a middle stem. They need special pliers to use them. Used for sheetetal. Limited range and not very high clamping force.

There is another sort (might be avdel - can't remember) that are a bit stronger and they have a half stem with a step that goes through the hole and another halfstem that is stepped and threaded.
You loosen the stem, push it through the hole then tighten up the knurled nut. They can be made quite tight and I have seen them in bigger sizes.