There are several brands and types for holding CAT taper tooling when off the machine.
They are used to tighten tools in CAT 40 holders. I have a cast iron one that I mounted on a bench near the mill.
CAT 40 tapers drop into it so you can, say, unscrew or tighten an ER collet nut. One I've got came with a tooling package of CAT 40 EM holders. Look around at the CAT 40 storage-cart type accessories too.
You only need about a 2in thick piece of steel, turn the taper on a lathe using your compound feed--leave a recessed area in the center ( to minimize the total amount of lapping needed ) and then then lap /test fit using an old toolholder. A narrow pair of lapped areas about 1/4 should suffice.
Alternately, use a cnc mill and a ball end mill....
Finally, bolt it onto an appx 4x8 flat plate such that that the taper shank extends through a hole in your setup bench.
You'll probably want to designate one of your toolholders as a "standard"....this is a perfect re-use for a damaged holder if you happen to have one kicking around...put it in the spindle and depth mike from it's flange to your spindle face...now, anytime you put this holder into your stand, double check to be sure you get the same reading on your height gage as you did to the spindle face...
Ideally, you would leave a little excess on your taper fixture and carefully face it off just after you finish lapping, testing with the the "standard" the goal being to get both the same which ultimately allow you to simply zero your height gage onto your fixture face.
Which 40 taper? If it is the NTMB 40, you can gauge off the back of the flange, so just machine something with enough bore to accept the taper, and a pair of projecting lugs to orient it (probably not necessary for measuring -- but nice for wrenching on the collet noses).
Make it of hex stock, so you can grip it in a milling vise for the wrenching.
If it is a CAT-40 or one of the other automated tool changer styles, it may not have as precise a surface location on the back of that grooved flange, so you may need the taper to be right.
You have a lathe -- right?
Is it big enough to have the compound travel long enough to cut the taper in one pass?
If so -- get (borrow?) a toolpost grinder, turn the taper close and then mount the toolpost grinder (and carefully protect all of the lathe's precision surfaces), and finish grind it with that.
Rough cut on your lathe, and use a toolpost grinder as above.
You could for a one-time job like this, make a mount for your toolpost to mount an air driven hand grinder and use that as the toolpost grinder. It will use a lot more electricity running the air compressor, but it will probably still cost less. You'll need a diamond for truing the stone in the grinder before you do the work.
I turned some tapered grinding wheel holders by setting the compound to the same angle as the original with a dial indicator. In the process I found that I had to clean up the worn dovetails. jsw
But when I need to be closer, I touch the spindle NOSE to a 3in block that's sitting on the workpiece or in the vise jaws and then after subtracting 3in, the resultant z axis negative reading becomes my Z axis fixture offset--then, touch the block once again, with the tool installed and enter the difference as (positive value) tool length offset.
The eBay item is what I'm doing. I'll watch eBay for one. Had NO IDEA they could go that cheap.
My current unit does +/- 0.003". Doesn't meet my needs. How accurate is yours?
My son has a multi thousand dollar presetter on his 1/2 million dollar CNC machine. He says normally a couple tenths accuracy, but he'll do a touch off check before building dies.
This will be my plan "B". I'd like to be able to set up a tool while the machine is cutting with another tool. This would be better than having to test cut every tool.
Someplace (CNCzone?) I seen plans for a homebuilt tool presetter that mounts on the table. i may look into that also.
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