Correct torque for hose clamps

Status
Not open for further replies.

Tom J

.
Sep 30, 2008
2,301
Catalina 310 Quincy, MA
Tight, but not too tight? That seems to work for me. Keep in mind the rubber in the hoses can compress over time, so checking all the hose clamps periodically is a good idea.
 

RichH

.
Feb 14, 2005
4,773
Tayana 37 cutter; I20/M20 SCOWS Worton Creek, MD
Not for clamps, but a close approximation can be found by estimating the threaded diameter of the clamp screw then going to: http://www.engineershandbook.com/Tables/torque.htm and using SAE grade 0-1-2 column ... these are 'max' torque values, so use ~80% of that value for a 'dry' screw. ;-)
 
Oct 2, 2006
1,517
Jboat J24 commack
I would say it depends on the clamp brand as the SS brand X stuff breaks pretty easy compared to the AWAB top shelf stuff

And it also depends on how soft or hard the hose is like exaust hose VS fuel line
 

Ross

.
Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
A plumber told me to just tighten it until it stops leaking.
 

Ross

.
Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
I use one of those 6-in-1 screwdrivers. The socket ends fit the screws perfectly. Remember if you are using inch sized clamps to use a torque wrench calibated in inch pounds but if the clamps are metric you must use a torque wrench calibrated in newton meters.
 
Feb 20, 2011
7,990
Island Packet 35 Tucson, AZ/San Carlos, MX
I use one of those 6-in-1 screwdrivers. The socket ends fit the screws perfectly. Remember if you are using inch sized clamps to use a torque wrench calibated in inch pounds but if the clamps are metric you must use a torque wrench calibrated in newton meters.
:laugh:
 
Dec 10, 2010
24
Starwind 19 Lake Perry
Not for clamps, but a close approximation can be found by estimating the threaded diameter of the clamp screw then going to: http://www.engineershandbook.com/Tables/torque.htm and using SAE grade 0-1-2 column ... these are 'max' torque values, so use ~80% of that value for a 'dry' screw. ;-)
Um, no.

The screws used in most hose clamps are not machine screws, they won't take any near that much torque.

Best way I've found in 30+ yrs for hose clamps (cars & boats) is to tighten them enough to start squeezing into the hose. On a boat, I'd recommend using two clamps for redundancy.

The clamps should be the type that are solid all the way around so the screw threads don't dig into the hose.
 
Feb 6, 1998
11,665
Canadian Sailcraft 36T Casco Bay, ME
I just busted out the torque wrench and tested an Ideal and an AWAB clamp. One Ideal failed at about 3 pounds and one failed at just under 4 pounds. Both AWAB clamps failed at about 8-9 pounds. Reading the scale at that low a torque is hard. So not an "exact" number. My "snap/click" torque wrench does not even go that low so had to use the needle arm torque wrench.....

If I ahd to shoot from the hip I would say safe working torque is somewhere around 1 pound for an Ideal/perforated style and about 2-3 pounds for an AWAB? The AWAB put some pretty good smush on the 1" wet exhaust hose before failing, the Ideal barely dented it. You'd never tighten one as much as I did the AWAB. 8-9 pounds is an unnatural amount of torque on a hose clamp. The Ideal/perf clamp however failed at a level you may go to trying to stop a leak...

I stopped using perforated clamps a long while ago..

I'll try and upload some pics later.

But the real answer is snug it up until you can't twist the hose on the barb easily or until it does not leak but DO NOT over tighten, especially perforated clamps... I used to have a two gallon bucket full of failed perf clamps but I finally got sick of collecting them and brought them in for a coffee & bagles worth of stainless scrap $$$$......
 
Nov 23, 2011
2,023
MacGregor 26D London Ontario Canada
Have you ever tightened one until it broke? Try it. Then you will know approximately how much you can reef on one. Not allot in my experience. I keep extras just in case.
 

Ross

.
Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
Tighten it up until it breaks and then back up half a turn. ;)To measure the torque you realy need a quarter inch drive torque wrench calibrated in inch pounds or even inch ounces.
 

higgs

.
Aug 24, 2005
3,627
Nassau 34 Olcott, NY
I think you are over thinking this. Get it reasonably tight - use two below the waterline and you will be fine.
 

higgs

.
Aug 24, 2005
3,627
Nassau 34 Olcott, NY
Additional thought: Your hose probably would not leak w/o a clamp. All you want to do is make sure the hose material is slightly compacted against the barb. That'll do it.
 

Ross

.
Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
Remember how very difficult it is to remove a hose from a barb after six months.
 

JohnS

.
Sep 25, 2008
177
Islander (Wayfarer/McGlasson) 32 St Georges Harbor
Remember how very difficult it is to remove a hose from a barb after six months.
And always use hoses about a foot longer than necessary, so that you can just use a utility knife to cut it off at the barb, and still have enough hose when you're ready to re-connect.
 
Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
I'm thinking that some of us don't do much DIY stuff.
1/4" torque wrench? I don't think my Mac Tools guy even carries one that small.
Real men don't use 1/4" torque wrenches so you are going to have to get the first mate to install all your hose clamps.

As for breaking free a stuck hose I find a pair of vice grip pliers to work fine. Just take the hose clamp off then use the pliers to rotate the hose on the nipple.
Alternately you can take a flat blade screwdriver and after taking the hose clamp off stick it between the hose and nipple, twist, then move around the circumference twisting as you go.
 
Jan 22, 2008
1,654
Hunter 34 Alameda CA
Tighten it up until it breaks and then back up half a turn. ;)To measure the torque you realy need a quarter inch drive torque wrench calibrated in inch pounds or even inch ounces.
That's what one of the techs at work told me was "Plumbers tight".:D I confirmed it with the plastic ice maker filter behind the refrigerator. Came home to a flood.
 

kenn

.
Apr 18, 2009
1,271
CL Sandpiper 565 Toronto
I tighten clamps just to one grunt and maybe one f4rt, max. Any more is overtightening. :D

I use one of those 6-in-1 screwdrivers. The socket ends fit the screws perfectly.
I have one of those 6-in-1 screwdrivers (PicQuik) with the hex shaft bits, only this one is the deluxe model with a reversable hex driver on the shaft - it fits 1/4" and 5/16" hex heads which makes it ideal for most SAE clamps. The fact it's a screwdriver gives great feedback and I rarely overtighten clamps when using it.
 
Status
Not open for further replies.