R8 tool changing

[balibalistic]

I've done a ton of searches,but cant find any pictorial/tutorial's on tool changing.i recieved a 3 page manual with my new mill/drill.so theres nothing that addresses how to remove chuck arbor to insert collets or end mill holders.how exactly is this done..,or could someone point me in the right place to look?

sorry..,im a total mill newb

[PinMan]

What kind of mill is it?
Is it a manual drawbar or pneumatic?


If its manual, there should be a spindle brake on the side of the head just below the motor. While holding the brake, loosen or tighten the drawbar that is on top of the head.

If its pneumatic, there should be a lever that loosens and tightens the drawbar automatically depending on what way you pull it.

[MIKE JEFFERS]

if it's an x3 slacken the drawbar (14mm spanner)(under the little tophat cover on top of the head )a couple of turns then a sharp tap with a soft face mallet or so and that should break the taper then just unscrew the drawbar occasionally tapping it to release the collet /chuck

theres a key in the x3 spindle that locates the slot in the collet (have a look see)
a bit of oil won't harm when you fit another collet too

[balibalistic]

These should come with an in depth manual for us newb's..this is the one i got:http://busybeetools.ca/cgi-bin/pictu...7&NTITEM=B1976

It came with a small drift key..,as you mentioned Mike.i need to see this hands on to grasp it..,im slow like that.

[protman16]

balibalistic,

There should be a large hex nut on top of the spindle step pulley, and a smaller hex nut above that. Use a large adjustable on the larger hex nut to hold the spindle steady, and a smaller adjustable or proper sized wrench to loosen the small hex nut above. Only loosen a few turn.
Next wrap the draw bar (small hex nut) with a soft faced hammer or chunk of aluminum. Then hold the chuck with your hand while the other hand completely loosens the draw bar.

If you do not have a large wrench to hold the spindle steady, you can change the belts to the lowest possible ratio to keep the spindle still while you loosen the draw bar.

[balibalistic]

I think your on to something here thanks for breaking it down for me!!

Originally Posted by protman16 balibalistic, There should be a large hex nut on top of the spindle step pulley, and a smaller hex nut above that. Use a large adjustable on the larger hex nut to hold the spindle steady, and a smaller adjustable or proper sized wrench to loosen the small hex nut above. Only loosen a few turn. Next wrap the draw bar (small hex nut) with a soft faced hammer or chunk of aluminum. Then hold the chuck with your hand while the other hand completely loosens the draw bar. If you do not have a large wrench to hold the spindle steady, you can change the belts to the lowest possible ratio to keep the spindle still while you loosen the draw bar.

[sansbury]

Little Machine Shop has a "manual" for the X2 that they wrote. You can download it from their site for free as a PDF.

[Climatepro]

Originally Posted by protman16 balibalistic, There should be a large hex nut on top of the spindle step pulley, and a smaller hex nut above that. Use a large adjustable on the larger hex nut to hold the spindle steady, and a smaller adjustable or proper sized wrench to loosen the small hex nut above. Only loosen a few turn. Next wrap the draw bar (small hex nut) with a soft faced hammer or chunk of aluminum. Then hold the chuck with your hand while the other hand completely loosens the draw bar. If you do not have a large wrench to hold the spindle steady, you can change the belts to the lowest possible ratio to keep the spindle still while you loosen the draw bar.

I used to have a RF version of balibalistic's machine maybe 20 years ago, and I have to disagree just a bit with protman. Everything he's said will work just fine, but it's overly complicated imho for this machine.

You can tighten the drawbar with one hand on the final drive belt and one on the wrench. With an R8 taper you really don't need to get the drawbar very tight, and two wrenches might lead a "newb" to overtighten. Please note! If your arms or elbows or shirt are anywhere near the on/off switch, don't do this! I had a set of recessed and guarded start fwd/start rev/stop buttons, no chance to hit them accidentally. Use your judgement and common sense. But still, the torque you put on R8 drawbar needs to be light enough that you can easily get the collets or tools out, so don't overtighten until you figure this out.

The other point I'm going to disagree about is using a soft faced hammer to rap the top of the drawbar with. I used to have a lead hammer sitting in the collet tray of my Bridgeport, and I used them for many years, replacing them when the faces would get too mushroomed. Finally I ruined a drawbar accidentally and had to buy a replacement. $22!!! What the heck was I doing all those years, wasting all that productivity to protect a $22 part? So now I feel a bit more grounded in reality. I've got a simple box end wrench that I use on the drawbar, and then I give the drawbar a sharp whap with the wrench turned so the flat part of the handle hits the hex (this lets the wrench flex a bit so it's not such a shock load to the spindle bearings). I was a bit nervous about it at first to be honest, but no mushroomed hex, and your hands just kind of learn how to hold the wrench and whack it right at the sweet spot so it's nice and comfortable. The point is NOT that I'm trying to wear out my drawbar because a replacement is cheap, the point is that the wrench is in my hand anyway, so it saves me ~10 seconds per tool change. Been doing that for years, just my 2 cents.

Reminds me of the 80s when people would put a black leather car bra on a piece of junk car to protect the painted sheet metal. Leather costs more than painted steel!

[philbur]

The key on an R8 is only there to hold the arbor while you spin the drawbar, it is not there to transmit torque during machining, although it will provide some contingency protection. One of the weaknesses of the R8 design is the key. The last thing you want to do is shear the pin off, it will almost certainly damage the spindle taper and replacement requires a spindle stripdown. The transmission of torque during machining is via friction between the male and female tapers, so the drawbar should be really good and tight (that’s a technical term).

Phil

Originally Posted by Climatepro You can tighten the drawbar with one hand on the final drive belt and one on the wrench. With an R8 taper you really don't need to get the drawbar very tight

[LeeWay]

It doesn't have to be monster tight with larger EM, but when using smaller ones, there is more steel that needs to compress to hold the EM. The smaller, the tighter they need to be to avoid shearing the key, as Philbur mentioned.
I use a ratchet on my drawbar and I probably put 25 to 35 foot pounds of torque on it. No knuckle busting to loosen it that way. I haven't had any slippage with this amount of torque.

[MIKE JEFFERS]

was gonna say use the wrench (spanner) to tap the drawbar but newbees etc
no disrespect intended
been doing this for years (near 30 now jeez) finger thight then 1/4 turn does it

[Climatepro]

Well, we're all talking in vague terms here except LeeWay (good job!) who has put a number to it. A quick test with my torque wrench, and I'm putting ~20 ft.lbf torque to it.

I'm by no means saying you'd rely on the pin/keyway to transmit the torque! That'll never work with a collet. I am saying you can hold onto the (sizeable) v-belt on this particular machine instead of reaching for a second wrench, and that this will enable you to apply enough torque that you'll have to really whack the drawbar to get it undone.

So I completely agree with you philbur, it needs to be good and tight. 20 ft.lbf is what I consider good and tight.