T-nut for an Aloris QCTP

#21
You can "wafer" build one quit easily with two pieces of suitable bar screwed together.... grind both pieces to size, much faster than filing. if you dont have a tap & die set already, your going to need on anyways
 
#22
You can "wafer" build one quit easily with two pieces of suitable bar screwed together.... grind both pieces to size, much faster than filing. if you dont have a tap & die set already, your going to need on anyways
Yes I have the tap, & grinding was going to be my first step to remove the most mass to get close to the thickness required, then filing for fine tuning. I like the wafer system though. Thanks.

Craig: I did make an error in D & E as E is larger. Thank you for that check-up.
 

PeterT

Ultra Member
Premium Member
#24
This might be similar to what historical is mentioning. With limited tools maybe you could make one like sketch, bolted together sandwich of for example two 1/4" plates vs. filing notches out of a single chunk of 1/2". I think this would give you a flatter contact surface for the underside of the compound Tee. The middle part is just along for the ride for general alignment & to give the post some meat to thread into. The trick is tapping the center hole through both plates. I think threading should work ok if they are securely pre-screwed together.

I'm treating this as a temporary thing. But you could also turn a T nut blank in your lathe once you have something in place & lop off the ears like picture.

You could hacksaw & file a solid but one consideration is even if you are out by a couple thou, you may only have one ear in contact with the compound & not really know it. The toolpost would probably be mounted well enough but I always consider any unequal forces like this on cast iron. Some people have cracked their mill tables with poorly made tee nuts. They don't fit so great, so they gronk them down and then ohsh*t. Cast iron doesn't like that too much & repair would be pita.
 

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Dabbler

Ultra Member
#25
When I mounted my AXA, it tried to do it as an accuracy exercise; I let the overall width allowance at .001 clearance per side athe the widest point, and the upper part of the T to have less than .0005 clearance - a slip fit. It turns out my compund was milled with a .001 taper on the upper part of the T slot, making it easier to insert one way, and nearly impossible to fit in the other way.

It isn't necessary to do this: the only thing that really matters is that the upper sides of the T slot are perpendicular to the hold down bolt/shaft. This can be best done in one setup on the lathe. Drill and bore for threading and turn the flats as a wide flange, and saw off with a hacksaw/file to fit.

@trlvn - nice job!