RCBS JR3 rocks front to back?

[ErikO]

I have an older JR3 that I just secured to my bench. The bench top is 3/4" ply so I figured I'd need a 2x4 mounting block under it to help secure it. I'm still getting a fair bit of play when I'm seating primers, what should I do? I'm thinking about getting a steel plate that I can drill a pair of hole into to allow the bolts to pass, but I can also use a narrower one that runs between the bolts. What would work better (besides a new bench top)?

[nascarkent]

You need more than a 2/4 . You need a more rigid set up , another large piece of 3/4 inch plywood glued and screwed to what you have.

[ErikO]

Ok, that makes sense.

My current benchtop is mostly cobbled together with what I had on hand and is ment to be portable. My next one will be two 2'x6'x.75" oak plywood sheets sandwiching a 2'x6'x.75" piece of particleboard. 1.75" wood screws and construction adheisive should make it almost the equivalent of a single piece of 2.25" plywood and also rock solid.

[Char-Gar]

My bench top is a 1.75" solid core door topped with 1/2" plywood. No rock, no bend

[dillonhelp]

At work, we have found that 1" thick particle board is stiff enough for reliable primer seating. An alternative is to mount a 2" x 10" plank to the front of your bench. That should provide enough rigidity for primer seating.

[ErikO]

Ok, I now have a plan. I'll be 'rebuilding' my portable bench with either 1" strandboard or a pair of 1/2" ply sheets glued & screwed as the benchtop. The sides and top 'shelf' will be 3/4" ply to lower the weight.

Thanks for the input, it has been totally appreciated!