These two “Pocket Hole” components overlay as shown. The procedure used was:
Both attempts produces the overlap geometry problem. Is there a way to eliminate this overlap?
Any help/guidance appreciated.
SU 2019 Model attached
Leg.skp (230.1 KB)
Sorry, I can’t see the problem. Turning on hidden geometry enables you to clean up the unwanted geometry.
Well, being new to this, when I try to edit the geometry, I get this mess!
Seems after the intersect operation, the PH components have been converted to raw geometry. But when I try to edit the overlap segments, the faces disappear. Maybe I am going about this all wrong.
It is night here, I’ll look at It tomorrow. Or someone else might have figured it out for you already
The pocket holes in your model have stayed as components, nested inside the caster mount.
Scale up a copy of the caster mount containing the intersecting geometry x100 or x1000. Make one of the complete pocket hole components unique, and do the same for the nested hole inside it.
Open one of the pocket hole components for editing - check that you can highlight the whole of its bottom surface with one click.With that face selected, Intersect faces with Model.
Do the same inside the other component.
Delete the surplus geometry that sits above the two surfaces.
Tried it without the scaling up, and without Make Unique, and some edges and faces seem too small to form properly - leaving holes - or deleting lines in one component would do the same in the other, leaving gaps.
The intersection isn’t perfectly symmetrical, which is why you can’t just leave the two components identical.
On further reflection I think it will be easier if you either explode the hole components, or cut them out of the component, and paste in place in the caster foot. THEN do the intersection, which will be geometry all in one context.
Thanks John, will try your suggestions. Maybe, I should have exploded the components before I cut them. Thought I understood the intersect tool, obviously not. Each time I venture into this territory, it is a humbling experience.
It can be complicated. Try my latest suggestion in the post, which I wrote as you were responding.
It does work.
What else have you in the file to make it almost 5MB? I purged the intersected model and got it down to 209KB.
John, it did work as you described. The intersection of the two holes looks funny, but I am not sure how it should look. Guess I will find out when I drill the pocket holes in actual wood. Thanks again.
And yes, the SU file I uploaded had a bunch of “junk” from other models. I forgot to purge before I uploaded. I cleaned up the file and uploaded a new, much smaller version.
Looking again at the construction I wonder if for strength you should glue the joint as well as using Kreg screws. Screws alone aren’t very stable against a twisting thrust from weight on the caster.
John, thanks for the insight. I am not a mechanical engineer, so have no clue how to construct a force diagram for this assembly. The legs are 3/4" plywood, the caster mounting plate is 2"x4" pine wood. The PH’s have their maximum holding strength in this configuration (no end grain insertion). The wheel assemblies will have three screws into plywood end grain (not ideal). Each caster is rated at 150 lbs. The workbench will have 4 total. Design is made of 2 - 4x8 sheets of plywood (60 lbs ea.), 1 - 4x8 MDF sheet (55 lbs ea.). So, 175 lbs (unloaded) distributed over 4 legs. Have no idea how to take into consideration the longitudinal force, especially if the workbench is loaded. Bottom line, glue is cheap, so will add as extra insurance.
How does this sound? Any/all advice appreciated.
I think I’d just put a solid block in there with the grain running vertical. This could also go high enough to be a support for the bottom shelff.
Only a thought,
Shep
Either what Shep suggests, or the same pieces as you have drawn, but just use ordinary screws into the caster mount from the outside of the plywood. And make sure the castor holding screws or bolts don’t interfere with the screws that hold the block on.
The thrust is now taken by the rebate round the block, which helps a lot, but I’d still use glue.
@john_mcclenahan, Shep/John, thanks for the ideas. Shep’s idea of extending the caster mount block up provides another support for the shelf and adds more glue surface for joint strength. I was going to use biscuits to join the two leg pieces, but am now thinking to use PHs since they’re used elsewhere. Using xray shows no screw interference.
Thanks to both of you for the ideas and support.
