Hey all, I’ve decide to attempt a simple horizontal frame by installing some drop in threaded inserts into my concrete garage floor. In addition to the anchors and bolts, I got some set screws to fill the holes when not in use. Here are some pics and links to what I bought.
EDIT: the drop in anchors require a 1/2" hole.
Drop in Anchor
Anchor Setting Punch Tool
Set Screws
Bolts
This is great thank you for sharing it. 
I am going use this for my horizontal setup, perhaps with a pinch spray of Corrosion X inside the threads to prevent rust lockup on the removable plug.
Good idea on the Corrosion X, I don’t have any but maybe a squirt of WD40 will suffice.
Regarding installation, setting the anchors dead nuts square to each other is important (how much I dont really know) and drilling four precisely located holes when there is risk of hitting aggregate in any of the desired anchor hole locations is challenging.
So…I was noodling the concept using a simple interface block that can anchor to those roughed in holes in the floor. The block can pass a second bolt with a slot cut end and countersunk from below to establish positional offset from the position of the cement floor hole, if needed of course.
But locking that block to a single bolt and resisting angular rotation while being easy to remove is still work in progress…
I’m not sure that the “need to be dead square” part is true. I think the calibration process accounts for being out of square. @bar mentions one of his setups was some 3" out of square here.
At any rate, my 8x12’ layout required 173" of hypotenuse to make it square(ish)…I’m out by about 1/8".
That is correct, they do not need to be a square.
That’s fantastic! Thank you both for confirming. Nice!!
Bar… How much lower can the belt end be from the cutting surface? If someone is using the floor of their garage and wants a spoil board, say the project is 3/4"plywood and the spoil board is 3/4"… That would mean 1 1/2" above the anchor… problem???
Jeremy
We haven’t really tested it, but I don’t think it would be an issue.
We might need to add a setting for entering that information for your machine, but that’s not hard to do
I thought I would ask before someone says they ran into the garage floor and ruined a bit. I want sure of it mattered seeing as how with the 4 arms, #1 will be quite a bit higher than #4. Lol
@jkitchens1971 @bar My plan is to cut some spacers out of 1/2" PVC pipe to put between the belt end and the garage floor. So something like this from top to bottom at all 4 corners:
Bolt Head > Washer > Belt End > PVC Spacer > Floor
sincitymakes wrote:
Bar… How much lower can the belt end be from the cutting surface? If
someone is using the floor of their garage and wants a spoil board, say the
project is 3/4"plywood and the spoil board is 3/4"… That would mean 1 1/2"
above the anchor… problem???
The frame that Bar is using puts the anchors for the belts at the same height as
the bottom of the spoil board, so that would be the same as anchors in the
concrete and a spoilboard on top of that (Bar has shown that exact setup as
well)
Now, like other things, what works for Bar and his accuracy needs will not
always work for everyone else (see the current calibration issues as a recent
example :-p ) but it’s not an unusual setup.
David Lang
Dean wrote:
@jkitchens1971 @bar My plan is to cut some spacers out of 1/2" PVC pipe to put between the belt end and the garage floor. So something like this from top to bottom at all 4 corners:
Bolt Head > Washer > Belt End > PVC Spacer > Floor
Try it, it’s cheap. But try to put a camera on a solid base watching the corners
to see if the anchor moves at all under tension. You may need something wider
and more solid than PVC if it does move.
David Lang
@dlang the spacers are just to keep the belt ends at the same level as the cutting surface. There is a 3/8’s bolt at least an inch into the ground. I don’t think I’ll get very much deflection…but I’ll check!
bolts in threads that are not tightened down (and sometimes even when they are)
can move in the threads. If you put a nut against the floor and tighten it down
against the floor rather than just having the bolt in the floor (or possibly, if
the bolt is bottomed out against the bottom of the hole) it will be stiffer.
David Lang
Good point, I think I have enough threads into the insert just by tightening by hand. ON my first calibration run, the anchor points all seem fine. I still need to get some plywood to do an actual calibration, that will come this weekend.
Great thread - this is an option for a super simple and cheap frame I’m interested in understanding long term. How well do these hold up over time. I was considering a big flat washer and nut tightened to the floor for stability.
@Gabe_Merrill I’ve only made one cut, but I noticed a few things about the setup…namely the belt ends climbed up the extra height available on the bolt shafts (probably happened during z axis moves). Other than that, I think it’s going to work out fine.
EDIT: I plan to remedy this with an additional spacer above the belt end on the bolt shaft.
here’s a pic of it in action (from another post i made)
I used a 3D printed anchor point glued to a 1/2" wood spacer along with a 3/8" Inch Zinc Plated Carbon Steel Concrete Knurled Drop in Anchor and a 3/8" x 4" Zinc Plated Eye Bolt.
Because I didn’t set the anchors, I can pull it up in an emergency (or to put away my toys) but it’s perfectly solid horizontally. If necessary one could set the anchor ever so slightly to firm it up but still have the instant release feature.
Tomorrow I’ll run calibration and report back.
That looks like a good setup!
