I’m including these clamps more as a warning rather than a positive vote for my purchase. If I had to rate it, I'd have to petition for a negative vote facility... but that's my opinion, without you asking.
Before yazall instigate a warning shot between my eyes about me owning 4 clamps, my urine-weak alibi is that some were bundled with the Kreg Pocket hole jigs I’ve bought in the past... while I'm not a pocket-hole fan, I've always upgraded to the latest model... love gadgets.
I will add that I have an Leigh D4R and their FMT which were/are not the best tools to use on melamine… consequently I channelled all my pockethole activity to melamine.
Now melamine is a slippery sucker and I found that these dedicated clamps didn’t hold the work together firmly enough to prevent some amount of slippage during screwing... real case of screw up! I found I had to clamp the bjesus out of the job with my Bessey clamps to get a perfectly aligned join.
I will add that I never use pocket-holes (and this clamp), on pine or other solid timbers that would not be as conducive to unwanted movement.
Well I then had 4 useless clamps... with that barrel (that only shot blanks), there was bugger all else where you could use them... Maybe?
NOPE… none seemed practical at the time... Though... if I was still pubescent,
On the lathe I turned a couple of “pads”
to attach to the holding ends of the clamps. I used a bit of Blue-Tack to hold one of the pads to the clamp, and finished up with a “somewhat workable” clamp,
My suggestion is to think twice if you ever consider buying one… and if you are like me, at least this is one way you can make them workable.
Now if I could afford them I may have not 4 but 6 maybe. ( Possibly I have a pocket hole ) OMG thats so sick I have 1 ...well almost 1, ... I made it myself, I think I showed you it some time back.
Perhaps you might sell off a few of the unwanted herd. Seeing 4 of them would make it appear you really liked them.
On your melamine, and sliding, try putting in a small patch of rubbery substance which under pressure grips down nicely on that slippery surface. Even an old balloon will allow for better grip.