Sherline Tongue Weight Scale question

How did you determine the tongue weight on the CAT scale? Direct weighing or subtracting weight of truck with weight with the truck hooked to the trailer?

I would rely on the Shurline scale over the CAT scale for that small of a reading.

Often stiction because of slight sideways pressure via placement of the tongue on the Sherline will cause erroneous readings. I would take several readings, moving the scale ever so slightly between them, and then average the readings. The height of the tongue will make the reading vary also. Make sure you measure at the same height each time - preferably when the trailer is as level as you can get it.
Barney

The Sherline is finicky as Barney suggested. Do several readings. The slightest bit of angle can throw off the reading.

lbrjet wrote:
The Sherline is finicky as Barney suggested. Do several readings. The slightest bit of angle can throw off the reading.

yup a good tool but not a certified scale. gives you good enough data.

The 620 came from subtracting the weight of truck with weight with the truck hooked to the trailer.
I'll retry doing several readings and let the trailer settle on the scale more. I asked Sherline and they suggest I "nudge" the scale a bit, because as others of said, how the weight is sitting on the scale has a lot to do with the accuracy. Ill also make sure I have the blocks the scale is sitting on perfectly level and stable and see what I get.

Were you sittin in the TV when you weighted at the CAT scale?

It's hard to say - CAT scale is certified, but is not accurate to such small weight differences. It's designed and certified to weigh things that weigh tens of thousands of pounds. (It's accurate, but not necessarily precise.)

Sherline scale is designed to weigh things at about the right range of weight for a tongue, but isn't certified. (It's precise, but not necessarily accurate.)

I'd be inclined to go with the Sherline weight, but you might want to get a third reading. (Another CAT Scale, another Sherline...)

atreis wrote:
(It's accurate, but not necessarily precise.)

???????? What a contradictory statement.

The issue with the Sherline was getting different readings with several tries.

I will bet you can weight on the CAT scale several times and the weights will not be more than 40 lbs different.

dnhx wrote:
The 620 came from subtracting the weight of truck with weight with the truck hooked to the trailer.

When you weighed the truck by itself, did you have the WDH mounted in the receiver with the WD bars in the WDH (or in the back of the truck)?

If not, the calculated "tongue weight" will be too high by an amount approximately equal to the weight of the WDH and bars.

Ron

RCMAN46 wrote:

atreis wrote:
(It's accurate, but not necessarily precise.)

???????? What a contradictory statement.

Accuracy and precision are not the same thing. Accuracy is how close the reading is to the "true" value, as defined by the central bodies that define and standardize those true values. Precision is how many decimal points the measure can be made at WHILE STILL BEING ACCURATE. (Overly precise is when more digits of precision are provided than can actually be measured accurately.)

As an example, the Cat Scale is certified to be accurate, and the actual value printed out on the sheet will lead you to believe that it's also precise, but it isn't. It might have given you a reading of, say, 4,578 lbs, when it is really only accurate to, say, 4,600 lbs. The rest is the computer taking the reading from the sensors and reporting it, but those sensors can't read accurately at that precision. (They ought to be rounding at whatever point their precision ends.)