Need help with T-Slots - Boring holes

[vacpress]

Kfong - good question. it could be a cheaper alternative to www.igus.com stuff. Looks about

http://www.woodpeck.com/14ttrack.html#492
$18 for 2 48" aluminum extrusions.
$10 for 24" of nylon guide bearing..

Probably pretty sloppy though, id imagine loading the slides against each other could work.. Maybe.

In my oppinion, IGUSs cheaper N series linear slides have a bit of slop in them as well. In comparison, IGUS 27mm rail is:
$30.00 for 2 48" extrusions
$20.00 for 4 "Drylin" Slide Shuttles

twice as much. maybe 3 lengths of the cheaper stuff with 3 4" long slides would be ok... maybe the would bind? ideas on that?

[kfong]

Seems like there is no side to side slop or very little, there is a gap it appears much like how tnuts are used. This won't be too much of a concern if they are mounted on the side of the gantry for the x axis and the gantry itself holds them in. Would be interesting if it does work. would be cheap, using multiple slides would drive up costs but would increase bearing loads. Would seem a good alternative to the rollerblade bearing setups I keep seeing, and certainly good enough for the model airplane cnc crowd.

Kin Fong

http://www.embeddedtronics.com/

Originally posted by vacpress Kfong - good question. it could be a cheaper alternative to www.igus.com stuff. Looks about http://www.woodpeck.com/14ttrack.html#492 $18 for 2 48" aluminum extrusions. $10 for 24" of nylon guide bearing.. Probably pretty sloppy though, id imagine loading the slides against each other could work.. Maybe. In my oppinion, IGUSs cheaper N series linear slides have a bit of slop in them as well. In comparison, IGUS 27mm rail is: $30.00 for 2 48" extrusions $20.00 for 4 "Drylin" Slide Shuttles twice as much. maybe 3 lengths of the cheaper stuff with 3 4" long slides would be ok... maybe the would bind? ideas on that?

[samualt]

Well, the tool I bought works. But I think a Forstner bit would work just as well. This Aircraft-Counterbore bit has a hole in the middle for a guide. After making the large bore hole you then have to drill-out the aluminum left by the hole in the bit. Which pretty much leaves a small hole in the bottom of your bore hole (anyone following that?).
So, why not just use a Forstner bit which results in the same thing. It is half the price and can be found at most hardware stores.

My biggest problem seems to be chatter when I'm drilling through that first slot (the T-slot). The sides want to vibrate. So tomorrow I will shove some wood in the slot to see if it doesn't make it more stable. Once the bit hits the flat bottom it gets as smooth as silk and cuts perfectly.

A 13/16 regular drill bit turned out to be a nightmare! It gouges the metal and likes to chatter way to much. It vibrated so bad it made the chuck fall off my drill-press. Yikes! Don't use a drill bit! Bad mojo!

So, for anyone reading this in the archives:
1. Use a Forstner bit. They're cheap.
2. Set your speed to about 1000 rpm on your drill- press (or there abouts).
3. Go very slow.
4. Spray some oil on the cut area. Makes it a smoother cut. But it's messy.
5. Use dowling or some kind of wood stuffed into the T-slot to keep it from vibrating. You might just use some t-nuts and bolts to form a bridge on either side of the cut and try to cut between them. I like the idea of wood better.
6. Be prepared for metal shavings everywhere!
7. Do some test cuts before ruining good parts. I'm still practicing.

Hope this helps somebody!