Sizing T-Slot Table for a BT800

[TechTony]

Aight Fellas, I made the mistake of buying a t-slot table clamp down kit this weekend from a local on craigslist... get home and break it out, and find out that the kit I purchased doesn't fit my t-slot table. So now I'm trying to size my t-slot table so that I can find a clamping system that will work. So I took some measurements and could use some assistance piecing it all together.

The measurements I took are based on this diagram:
http://enginuitysystems.com/pix/tools/T ... ns_800.png

Values:
A1: 12.20
B1: 20.25
C1: 7.70
D1: 7.57

Based on the chart on the diagram, I think this gets me close to:
A1: 12
B1: 19 - 21
C1: 7 - 8
D1: 7 - 11

Any pointers about what I should be looking for in a clamp down kit - specifically in finding one that fits my table?

[GlennW]

This should be the correct size.

http://littlemachineshop.com/products/p ... ategory=11

Others probably sell the same kits.

[TechTony]

The problem I was running into was that the nuts that are supposed to be anchor points and slide into the t-slots are way too big, even though the all thread pieces were sized appropriately.

[SteveHGraham]

WAIT! You can buy the nuts and studs separately. Grizzly sells them. You may be able to find smaller nuts that fit your studs.

[John Evans]

Ya got a mill ,make your own. Just do NOT tap all the way through !!

[TechTony]

Ya got a mill ,make your own. Just do NOT tap all the way through !!

While I appreciate the vote of confidence, and did actually have this inclination initially, I don't know that I quite have the tooling or the knowledge to do so just yet. I still have no clue how to cut threads on this machine as of yet. Someday.... but not today.

[TechTony]

WAIT! You can buy the nuts and studs separately. Grizzly sells them. You may be able to find smaller nuts that fit your studs.

Sounds like a much cheaper solution as the rest of the set it definitely usable! Thanks!




Think I'll also look at shaving down the t-slot anchors in the set I bought, tonight when I get home. Maybe I can just take a little material off each side of the anchors and make uhm work... kinda disappointed in myself that I didn't come to that conclusion sooner.

[SteveHGraham]

The T-nuts may be hardened, so watch out.

If you decide to make your own, you will need a tap. I would guess a bottoming tap is best, because you want the threads to go almost all the way through, but I could be wrong.

[10 Wheeler Rob]

You can tap all the way through and stake the back side with a cold chisel in two or thee places around the thread so the studs will not screw all the way through. Some of the ones I bought were manufactured that way.


Rob

[stevec]

The T-nuts may be hardened, so watch out.

If you decide to make your own, you will need a tap. I would guess a bottoming tap is best, because you want the threads to go almost all the way through, but I could be wrong.

A bottoming tap is difficult to start tapping with, just use a starting tap but don't tap all the way through so the stud will bind as it gets into the tapered threads.

[pete]

We should probably add why you want to stake the botton of those tee nuts or not tap them all the way through. If the stud can go right through the nut it will bottom out in the tee slot and start jacking up the nut. That chews up the bottom of your tee slot and after enough of that the tee nuts and tee studs can start to get real tough to slide past the damage. Then you need to machine, file, or stone out the problem areas. Jacking up the tee nuts can so I've read make it easier to break out part of the table. I'm not fully conviced of that, but better to not do the damage to start with, and why take a chance on ripping out part of the table if it can cause that.

Hard to say if your hold down set is hardened or not. A file would tell you though. My Tecos are, but the much smaller metric set I bought to fit my lathes cross slide from LMS is pretty soft. The threads weren't the best either, so I ran a die down all of them to clean them up. Much nicer to use after that.

Tapping in the mill to at least get the thread started straight is pretty easy. Lot's of videos around on Youtube showing how a lot of it is done. Power tapping through threads or deeper holes that are blind without a tapping head takes good quality and a bit more specialy designed taps than than the normal set of cheaper or even good quality hand taps are. But standard hand taps can be used to get the threads started. You can let the tap spin in a drill chucks jaws if it's not fully tightened as a way to prevent broken taps. But that's tough on the chucks jaws if enough of it is done. A little practice on scrap material to fine tune the method and you can start the mill, shut it off and lower the tap so it starts cutting as the mills spindle winds down to a stop will get enough threads started straight if you time it right so they can be finished by hand at a later time works pretty well.A mill that doesn't have reverse makes it a lot more tedious. Whenever possible I always use the machine that drilled the hole in the first place to get the tap at least started straight is much easier than trying to get them started straight by hand. I'd do that even if I had to rotate the spindle around by hand.

[10 Wheeler Rob]

Many hand tap wrenches have a hole in the center of the tap handel, I just put a piece of round stock that fits it to it in the mill Chuck or collet and let that guide the tap straight as I hand drive the tap to start it straight.

Rob