Rubber Stainless Steel P Clamps with larger than 6mm or 1/4 mounting hole

[kramttocs]

Has anyone come across any of these? The 6mm or 1/4 works in a lot of places on our trucks. For those locations with 8mm bolts I just enlarged the hole but that's a bit of a pain to do without either taking forever, losing skin, or twisting the clamp into modern art.

I've found some zinc-plated but would like stainless.

Would also settle for any tricks to enlarging the 6mm hole.

Thanks

[1986F150Six]

Like this, Scott?

https://www.ebay.com/itm/223507234755?chn=ps&norover=1&mkevt=1&mkrid=711-213727-13078-0&mkcid=2&itemid=223507234755&targetid=4580840328167961&device=c&mktype=&googleloc=&poi=&campaignid=403204656&mkgroupid=1235851284511226&rlsatarget=pla-4580840328167961&abcId=9300377&merchantid=51291&msclkid=150fe43b02811d22ba6d8428f5e75110

[Gary Lewis]

David - I haven't been able to find the size of the hole in that listing.  Am I missing it?

Scott - I feel your pain on enlarging the hole.  I've pretty much given up on that since I made pretzels out of several of them.  But, what has worked, albeit very slowly, is to use a tapered round file to enlarge the hole.  But, as said, it is slow and especially so in stainless.

[1986F150Six]

Gary Lewis wrote

David - I haven't been able to find the size of the hole in that listing.  Am I missing it?

I don't think it is stated. Looking at the different sizes of rubber covered "P", the mounting hole appears to be the same.

[Rembrant]

I call these things cushion clamps, and I have them all over my truck as well. I used the 1/4" ones for my brake lines, and larger ones for my electrical and fuel lines inside the frame. I pretty much threw away all of those old plastic frame clips that were in the frame.

They are difficult to enlarge the holes. Been there, done that, bought the Bandaids.

Only thing I can think of for drilling them out would be to make a little jig/guide for it.
I have some random pieces of aluminum plate here that use for various things, but I'd take two pieces...1/4" or 3/8" thick, and squeeze the clamp between the two and then clamp in the Vice, with the cushion clamp just outside of the visa jaws of course. Or you could use steel...but have a guide hole in each piece and have the cushion clamp pressed between the two.

Am I making any sense?...lol. It's making sense to me...lol.

[Gary Lewis]

That makes perfect sense, Cory.  Just sandwich the ears of the clamp between two pieces of metal and drill through.

But I'm wondering how to center the holes in the ears to ensure you get the larger hole where it needs to be.  It would be easy if the plates had the smaller sized holes in them as you could line it up with a bolt or even a phillips screwdriver.  But then you have to drill the plates out each time.

What if you had an alignment tool that was the size of the hole in the plate on top and then went down to the size of the original holes in the ears?  Use it to align the ears, clamp in the vise, remove the alignment tool, and drill through.

[kramttocs]

Thanks all.

Cory, I follow what you are saying. It wouldn't take much to eyeball-center the clamp hole in the guide holes and that would be close enough.
Or embellishing a bit:
Outline the clamp's ends in one piece of plate
Route out a shallow trough matching the outline so the clamp sits in there
Drill a hole through the existing clamp hole (~6mm) into both plates (grooved and not)
Remove clamp, enlarge hole in both plates to desired side
Reinsert clamp, enlarge hole in clamp

[kramttocs]

Posting at the same time with similar thoughts. Yours would be easier.


So if enlarging to 8mm you could have a reducer that is 8mm OD and 6mm ID. Using a 6mm bolt to line it all up.

[Gary Lewis]

I was thinking of an 8mm bolt turned down to 6mm on the end.  But that leaves the bottom plate to align.
 Your idea of a reducer is better as you could have two, one top and bottom, to align the clamp.

[kramttocs]

With one to spare :)

https://www.amazon.com/uxcell-Bearing-Bearings-Wrapped-Bushings/dp/B07JLPJL9D/ref=sr_1_5?dchild=1&keywords=6mm+to+8mm+sleeve+bushing&qid=1611932026&sr=8-5

[Gary Lewis]

Yes!  

[kramttocs]

Thanks again all!
Going to measure the holes in the clamps for a better idea of the size and get some of these ordered.

[Gary Lewis]

Keep us informed as to how it works as many of us have similar problems.

[kramttocs]

Got around to looking at this today. Wanted to create something simple using just what I had in the shop before I did anything real involved.
Took some nail strap, cut it in pieces, bolted them together, and drilled out one hole pair to the desired final diameter.

The photos are of the 3/8 one but created a couple for the other sizes as well. 3/8 is the largest I'll ever use with this clamp style.

After centering the clamp using the bushings, I placed some small c clamps on either side to really hold it in place and then stuck it in the vice. Normal drill bits still grabbed but step/uni bits worked without issue. Drilled from both sides.

As discussed earlier, a much nicer jug could be made where each side would have a cutout just deep enough for the two ends of the clamp to sit in. That way you aren't just relying on the jig clamping pressure to prevent spinning.

No more time than it took to make this super simple jig and since it works, this is probably good enough for my needs but for those with a mill, it'd be neat to see something really nice. Picturing a set of plates that have a bolt, slot/hole for size A, bolt, slot/hole for size B, etc.

[Gary Lewis]

That's cool, Scott.  Well done.

But I can envision what you are suggesting - a block with a slot the size of the strap, a plate to go on top, and a hole the size of the finished/to-be hole.  Plus a bushing to center the strap's smaller hole in the bigger hole.  Clamp all that in the vise and drill away.

Or, put bolt holes in it so it can be clamped that way and then put the thing in the mill's vise to be able to drill more cleanly.

[kramttocs]

Yep, exactly.