R-8 collet key

[visenfile]

Back on the spindle key...newbie here learned the hard way that the keys don't mean much . The HF mill drill would not accept R8 collets . After advice I filed down the key slightly. Apparently that is fairly common on the downscale equipment. The gripping power of the taper is laid out elsewhere in this forum and is quite impressive , a reason not to tighten the drawbar over ? 10-15 ft lbs, according to members.

 

[TOOLMASTER]

To loose and your bit may start drilling..

 

[Walsheng]

Back in the day (boy I hate that I am old enough to say that) I had many many apprentices. The one thing I learned was the smaller the person, the tighter the draw bar. Not so much anything else in the shop, but the draw bars on Bridgeports. I had one apprentice who was 6"5" and 280 pounds and he never over-tightened anything. Had another that was 5"2", maybe 110 pounds soaking wet and had to stand on a 10" platform to reach the drawbar but somehow had the ability to tighten that sucker so much you needed to hammer the wrench to get it loose. It took a year of rapping him on the knuckles to break that habit. Come to think of it I probably would get arrested for doing that these days.
If everything is clean and dry it doesn't take much to hold the tool and they pop right back out without too much effort.

John

 

[Bill Gruby]

Don't worry about it. Most people end up removing it.

Actually, most of time it removes itself and nobody replaces them. :rofl:

"Billy G"

 

[FanMan]

The big question is why the manufacturer even bothers putting the key in in the first place?

 

[xman_charl]

Manufacturers like to lock you down to their tooling.

Manufacturers know some of those keys are going to fail.

Manufacturers know some of those buyers will just purchase another machine, instead
of fixing it.

Manufacturers know those R-8 collets can spin in the spindle.

Charl

 

[hvontres]

The big question is why the manufacturer even bothers putting the key in in the first place?

Probably because they want to sell more "Quick change" tooling adapters once users get tired of spinning the damn collet around the bore three times while trying to line up that darn keyway :roflmao:

Plus, I think having the key makes a power drawbar work much better, since without the key your collet will just spin once it loosens up a bit.

 

[darkzero]

The big question is why the manufacturer even bothers putting the key in in the first place?

Bridgeport designed the R8 slot so that the R8 collet does not spin while tightening/loosening the draw bar. One hand would be turning the draw bar & the other hand holding the spindle brake so the slot allows no need to hold the R8 tooling. Other manufacturers just follow the R8 standard.

I can understand their reasoning for it but I don't install R8 tooling that way. I don't have a spindle brake, BP sindles spjn much more freely because of the belt drive. I hold & push the R8 all the way up into the taper, tighten the drawbar fully by hand, then tighten with a wrench, I have no need for the R8 pin.

 

[visenfile]

To beat it more to death... The H Frt mill drill was purchased with E 25 collet adapter from H Frt, but did not include 3/4 end mill, so I bought a set of R8 collets to get the 3/4. The R8 would not engage spindle and being a newbie I suspected the collet. After help from little mach shop and finding the R8 Bridgepoert dwg it became obvious the pin was the problem so I filed it back with a half round file.

I contacted tech dude at H Frt and he actually answered my enquiry about how to tighten the spindle. "Grab the spindle drive pulley with one hand..." while tightening. I made a wrench with fingers that reach down over the draw bar nut into the spindle spline-much better.

 

[xman_charl]

Took out those set screw thingys. Enco Square column mill.

Made an adapter that will fit those holes, "lock spindle, everything", when
broaching splines, pulleys, etc.

Clamp surrounds column, sticks into spindle, oh what fun, if you turn motor on.

Charl