To get an entry in, a piece I call “magnetic door catch for Snap On KR274”
The cabinet is a side hanger of a certain age that never had any door latch provision except the cam lock. This is REALLY annoying, since it meant that to keep the door from opening, the key must be used. It rattles if bumped. The lock cam turns on it’s own if the key is left in, which makes opening and closing more annoying, and also scrapes up the paint.
So, a magnet.
The model:
A rare earth magnet in the hole is attracted to the center shelf of the box when this in mounted in the flange of the door:
to hold the door closed
No fasteners used. It pops into the hole in the flange and is held with no play by the door skin.
How this was machined:
A pocket was cut in the wasteboard to hold a chunk of Nylon rod:
The pocket stock-to-leave was adjusted for the bore operation (the last op) several times and the operation repeated to get the correct fit.
The origin is in the pocket, centered in x-y, but level with the bottom of larger bore. This will be shown later. Setting zero to bore the pocket required finding the wasteboard surface and setting the z there to be 5mm t get a 5mm deep pocket. This made it unnecessary to reset the zero at all.
The stock:
fixtured
for these operations:
The setup for the first end allows for the stock oversize on the other end, so there is bottom extra stock as well as top.
The nubbin and edges are chamfered using a ball end, since it is a small chamfer. Just enough to break the edge to install the part when done and make inserting in the fixture hole for the other end easier
The machining:
Then came the other end. The same fixture was used. so the origin is actually within the part.
This allowed the origin for the first end to be at the surface of the raw stock, which makes things a lot easier. It was easy to place it for this setup, since it is a point on the plane cut on the first setup, a plane in the model
There is less surface to grip and more flex since it isn’t the full round. For a one off, I just reduced the tool engagement a lot to avoid pulling the part out. May not have been needed, but whats an extra 15 minutes?
followed by boring the hole for the magnet. The bore was done with an adaptive operation, and I adjusted the parameters for periodic retraction (by limiting the pass depth) to help clear chips.
Note the skin left over. I expected this as a possibility, but didn’t worry about it. Came off real easy. Minor dimensional adjustment would take care of it on a repeated job.
Installed the magnet using a wood dowel as a punch (I have no brass punch small enough)
and installed in the cabinet. The hardest part was putting the hole in the door flange. It is 18Ga (nearly 1.5mm) steel.
I didn’t bother to fancy the model up. Just a quick job to meed a need. No artistic merit here. Just
mag-catch.zip (1.9 MB)
should anyone want it.