How I measure seating force with Forster Co Ax Press

[dogdude]

Bginvestor's post #12, has me in a Stranglehold

 

[johara1]

First the numbers you get with a torque wrench are not taking into account for all the mechanical advantage of the press, you are getting the number what you are pulling, not at the seating force...... on a K&M set up it is right on the seating stem and not at the handle. no linkage and mechanical advantage to the torque wrench...... jim

 

[Bginvestor]

I tried a torque wrench on my Rockchucker but the string and duct tape kept breaking.

yikes!

 

[Bginvestor]

First the numbers you get with a torque wrench are not taking into account for all the mechanical advantage of the press, you are getting the number what you are pulling, not at the seating force...... on a K&M set up it is right on the seating stem and not at the handle. no linkage and mechanical advantage to the torque wrench...... jim

understood.. but doesn't matter to me. the mechanical advantage is constant.. Its all about a relative , consistent reading from brass to brass.. thx

 

[johara1]

understood.. but doesn't matter to me. the mechanical advantage is constant.. Its all about a relative , consistent reading from brass to brass.. thx

No, all the pivot points and sliding on the rods are very very dependent on on lube and side load. You would need a load cell to eliminate all the variables on a regular press...... jim

 

[Bginvestor]

No, all the pivot points and sliding on the rods are very very dependent on on lube and side load. You would need a load cell to eliminate all the variables on a regular press...... jim

Nope! Disagree. Pull down at a similar rate / alignment of wrench and get quality / useful measurements.

 

[johara1]

it will not work that is too crude is why you get all over the place readings. With the K&M and the force indicator 90% will be with in a lb. other will regulate to sighters ..... jim

 

[Bginvestor]

it will not work that is too crude is why you get all over the place readings. With the K&M and the force indicator 90% will be with in a lb. other will regulate to sighters ..... jim

Sorry, definitely do not agree that its "too crude".

By the way, I've own a K&M w/ force gauge using arbor, and I know what those readings look like.. FYI

 

[johara1]

so what do the readings look like on the K&M with a force indicator?.... jim

 

[jackson1]

Not sure I agree with what you are doing, but I give an "A" for innovation. Like to see thinking out side the box.

 

[Bginvestor]

so what do the readings look like on the K&M with a force indicator?.... jim

Hey Jim,

Please don't base your complete opinion on the first set of data that I posted. I understand where your coming from, it doesn't look great (spread). Actually, I had several measurements that I could feel "different", one was definitely out of family. Not my best reloads. lol

Subsequently, my latest have had much tighter groups of measurements.

To answer ur question though, I don't have any K&M measurements to offer up, but I do remember that peak force was somewhere within 5 lbs for some batches (I think). Within 1 lb seems impressive. thx

 

[INTJ]

I have a 21st Century Hydro Seater and sort my LR BR rounds by seating pressure. Most seat to within a few PSI, and the ones that are 10-20 PSI out of the norm become sighters. However, we are starting to see evidence that a 20 PSI difference doesn't show up on the target.

More testing needs to be done, but I suspect it will take a 50 PSI difference or greater to make a difference. Seating force isn't really a pure measurement of neck tension since varying amounts of lube in the case neck will change the reading. Variations in seating force can also change seating depth, which can indeed show up on the target. Now seating force will show which case aren't springing back as much, and that will change neck tension.

Given all that, I would be fine using a non-pressure reading arbor press and separating out cases that are noticeably harder to seat. This of course assumes I have cleaned the necks all the same as well as kept all my brass prep and loading techniques consistent.

Now if indeed a 50 PSI variation will show on paper, and if our usual single stage presses are not sensitive enough to feel that when seating bullets, then the torque wrench attachment idea has a lot of merit. It will require testing to see what readings will make a difference.

 

[Bginvestor]

I have a 21st Century Hydro Seater and sort my LR BR rounds by seating pressure. Most seat to within a few PSI, and the ones that are 10-20 PSI out of the norm become sighters. However, we are starting to see evidence that a 20 PSI difference doesn't show up on the target.

More testing needs to be done, but I suspect it will take a 50 PSI difference or greater to make a difference. Seating force isn't really a pure measurement of neck tension since varying amounts of lube in the case neck will change the reading. Variations in seating force can also change seating depth, which can indeed show up on the target. Now seating force will show which case aren't springing back as much, and that will change neck tension.

Given all that, I would be fine using a non-pressure reading arbor press and separating out cases that are noticeably harder to seat. This of course assumes I have cleaned the necks all the same as well as kept all my brass prep and loading techniques consistent.

Now if indeed a 50 PSI variation will show on paper, and if our usual single stage presses are not sensitive enough to feel that when seating bullets, then the torque wrench attachment idea has a lot of merit. It will require testing to see what readings will make a difference.

I agree , good stuff