[digits]

Hi guys, I see that Tormach have a 30-taper spindle cartridge as a spare part - has anyone actually got one on their machine, and if so, what flavour of 30-taper tooling does it take? Does it use a screw-in drawbar, or pull-studs in the tool holders?

Also does anyone know what the max safe RPM this cartridge spindle is good for?

Cheers.

[redrider9112002]

I dont have it, but I want it. Its bt30 tooling with a drawbar. curious about it to. I think it would make better cuts to. I havent asked if it was still avalible, have you?

[philbur]

I think the only real advantages are:

1) If you already have a lot of ISO30 tooling.

2) If you want to run an ATC.

3) It has drive “dogs” so it will not slip under heavy load.

It is possibly a bit more rigid due to the longer taper but I doubt you will notice the difference in practice.

The disadvantage is that you can't use the quick change TTS, so manual changes take longer. You could possibly make a special collet!!

Phil

I dont have it, but I want it. Its bt30 tooling with a drawbar. curious about it to. I think it would make better cuts to. I havent asked if it was still avalible, have you?

[nicad]

Digits-

I had emailed Greg at Tormach about some of these same things. Here is his reply (please note this was in May of 2006, so prices are sure to have changed since then).

*****
Assembled R8 cartridge is $505.75 (pn 30306) and the matching drawbar is $13.50 (pn 30507). We also have an assembled BT30 cartridge for $552.50 (pn 30505) and matching drawbar for $13.50 (pn 30506).

Speed, temperature, preload, and bearing life are all related. There is no specific limit, but with the bearing preload we're using the bearing stays below 200 F during continuous operation of 4500 RPM. I think 5000 RPM would probably be OK but the temperature during constant operation would probably get to 220 F or so. Beyond that you would begin to get much shorter bearing life. Replacing with a higher quality of bearing could get you well above 6000 RPM but the cost would be much higher.

Greg
*****

[H.O]

Hi,
Hi I don't have either the PCNC or the 30 taper spindle but here's my thoughts on the subject.

Specifiying the tool-nose as BT30 seems to indicate that it IS setup for toolholders with pullstuds ie auto or semiauto toolchanges. If it indeed IS a spindle with springloaded drawbar I'd get it in a heartbeat.

/Henrik.

Edit: Found this document on the Tormach site and it says:
BT30 Spindle Cartridge: This is a drop in replacement for the R8 spindle cartridge. It comes with a conventional draw bar, no stud puller. PN: 30505 $552.50

[digits]

Hi Guys, thanks for the replies. I have also contacted Tormach who were very helpful, even though I don't have a PNC 1100.

As a couple of you have already said, it is just a screw-in drawbar, but I would have thought that modifying it to take a stud puller would be cheaper/easier than building a pull-stud 30-taper spindle from scratch. I guess it'd have to be rebored from the pulley end down, but as far as I can see, it wouldn't need to be that high precision - the complex parts can be contained in the stud-puller assembly. Henrik - does that sound reasonable?

At the moment, I've only got one 30-taper tool holder that I bought for £10 just to get a feel for the size of them. My machine is actually R8 but I don't really have much of an investment in R8 tooling as I've been using a rapid-changer in a 3/4" R8 collet so far. Unfortunately I seem to have mangled it in a 200+ IPM head crash, and as a new one would set me back $350+ I don't think I'll bother replacing it. This leaves me with no way of making an ATC with my current setup and a shed load of expensive ER16 collets. There doesn't seem much difference in the prices of collet chucks for BT-30 and R8, so I'm tempted to give BT30 a go...

Cheers.

[philbur]

Before I shelled out on the spindle I would do some preliminary design work to ensure the stud puller assembly is going to fit inside the spindle bore without to much loss of wall-thickness. Spindles shafts don't usually have to much extra meat on the diameter as the design often targets the smallest possible bearing sizes.

Phil

but I would have thought that modifying it to take a stud puller would be cheaper/easier than building a pull-stud 30-taper spindle from scratch. I guess it'd have to be rebored from the pulley end down, but as far as I can see, it wouldn't need to be that high precision - the complex parts can be contained in the stud-puller assembly. Henrik - does that sound reasonable?

[digits]

Before I shelled out on the spindle I would do some preliminary design work to ensure the stud puller assembly is going to fit inside the spindle bore without to much loss of wall-thickness. Spindles shafts don't usually have to much extra meat on the diameter as the design often targets the smallest possible bearing sizes.

Phil

Thanks - that's very good advice Phil. I guess I could always use an air-wrench style auto-drawbar if there's no room for a stud puller...

[H.O]

Hello,

I guess it'd have to be rebored from the pulley end down, but as far as I can see, it wouldn't need to be that high precision - the complex parts can be contained in the stud-puller assembly. Henrik - does that sound reasonable?

It's hard to say without seeing a drawing (with dimensions etc) of the spindle in question. Theroeticly you should be able to open up the spindle bore from the pulley side and insert a tube which houses the drawbar assembly. BUT, as Phil points out, the shaft diameter may be too small to able to that. The lower part is probably fine but the upper bearing may become a problem. Again, without the actuall spindle or an acurate drawing of it it's hard to say.

But what the heck do I know, my BT30 spindle still isn't running :-( working on that though....

/Henrik.

[DareBee]

I don't have a Tormach.
The biggest advantage with the BT30 is being able to preset your tools and do tool changes with having all tool heights set ready to go. With an R8 you cannot set tool lengths, period.
I have seen those R8 adapters that give quick change but you lose rigidity and accuracy with that - think about it - there is 1 more joint (run-out and rigidity issues) and tool length from spindle nose increases (huge rigidity issue).
Even without the pull stud for the BT throw on a power drawbar and have a great time.

[digits]

I don't have a Tormach.
The biggest advantage with the BT30 is being able to preset your tools and do tool changes with having all tool heights set ready to go. With an R8 you cannot set tool lengths, period.
I have seen those R8 adapters that give quick change but you lose rigidity and accuracy with that - think about it - there is 1 more joint (run-out and rigidity issues) and tool length from spindle nose increases (huge rigidity issue).
Even without the pull stud for the BT throw on a power drawbar and have a great time.

I don't see why you wouldn't get repeatable tool lengths with an R8 ER collet chuck - and it'd only add about 1" to the spindle nose, so I doubt it'd be too bad for rigidity either. I seem to get the same runout with one as in a direct R8 collet too...

There is actually a patented system for an R8 pull-stud drawbar system for Bridgeports - it is pretty pricey though. Got me thinking though, you could probably saw off the straight part of R8 tool-holders to just leave the taper, and then add a stud-puller that fits in the space usually occupied by the straight shank. Wouldn't leave much contact area though, and would mean making your own toolholders...

[digits]

Before I shelled out on the spindle I would do some preliminary design work to ensure the stud puller assembly is going to fit inside the spindle bore without to much loss of wall-thickness. Spindles shafts don't usually have to much extra meat on the diameter as the design often targets the smallest possible bearing sizes.

Phil

When I started making enquiries about both their spindle cartridges, the guys at Tormach were actually kind enough to send me a dwg file of the R8 spindle without me asking for it. Looking at that, the spindle is about 25mm at its narrowest and is bored to 14mm for the drawbar. The top of the ISO 30 holder I have is 18mm in diameter - so I guess that's the narrowest part of the taper. Not a lot of space, but it might work for a small diameter DIY pull-stud.

[zephyr9900]

The biggest advantage with the BT30 is being able to preset your tools and do tool changes with having all tool heights set ready to go. With an R8 you cannot set tool lengths, period.

With the Tormach Tooling System, you certainly can! I have all my tools (except for my new flycutter, which I need to modify) preset in TTS holders and use PCNC/Mach3's tool table. With the TTS, the R8 collet only serves to center the toolholder and tension the flange on the toolholder against the spindle nose. It is very rigid and repeatable. Tool changes take less than 30 seconds too.

You might still want BT30 toolholders, but go to http://www.tormach.com/document_libr...lingSystem.pdf and read about the TTS and see what it offers relative to the BT30... All I can say is, I'm really happy with mine!:rainfro:

Best regards,

Randy

[redrider9112002]

The bt30 spindle uses a draw bar... Why make it more complicated than it has to be.. The advantage of the bt30 would be surface finish due to the rigidness of the BIGGER taper. and you could still have the tool height offsets. Any time you add a link in the tooling, you weaken the stability of the tool. I have a tormach and the TTS and its great, but I want the best possible tooling system and I think the bt30 is the way to go. Quality is the issue here. Quality of cut and parts. As is tooling availability. I'm having a hard time finding face mill heads that are aluminum specific. Just my thoughts...

[philbur]

I'm not sure the 30 taper is significantly stiffer that the R8. It is dimensionally the same as the R8 (angle and max diameter) but it does have a longer contact surface. However the R8 has a large, parallel diameter located a long way above the taper so this will provide added stability to compensate.

Just some thoughts and opinions.

Phil

The bt30 spindle uses a draw bar... Why make it more complicated than it has to be.. The advantage of the bt30 would be surface finish due to the rigidness of the BIGGER taper. and you could still have the tool height offsets. Any time you add a link in the tooling, you weaken the stability of the tool. I have a tormach and the TTS and its great, but I want the best possible tooling system and I think the bt30 is the way to go. Quality is the issue here. Quality of cut and parts. As is tooling availability. I'm having a hard time finding face mill heads that are aluminum specific. Just my thoughts...

[DareBee]

parallel diameter located a long way above the taper so this will provide added stability to compensate.

I disagree.
For a parallel dia to assemble it must have clearance.

The bt30 spindle uses a draw bar... Why make it more complicated than it has to be.. The advantage of the bt30 would be surface finish due to the rigidness of the BIGGER taper. and you could still have the tool height offsets. Any time you add a link in the tooling, you weaken the stability of the tool. I have a tormach and the TTS and its great, but I want the best possible tooling system and I think the bt30 is the way to go.
IMO clearance = slop/play not stability.

Thank you

[philbur]

Depends on the size of your hammer.

Yes of course you are right but:

1) For every 0.01mm clearance at that top end how much deflection transmits through the taper due to the tool loading vs how much does the tool itself deflect.

2) For a given pulling force a collet taper with less contact surface area will be more firmly pulled into the spindle taper.

3) An R8 collet allows for less overhang and therefore potentially less tool deflection and also a smaller bending moment at the spindle taper.

4) An R8 is more than rigid enough for the capabilities of the motor/VFD combination on the Tormach.

Just trying to point out not to get too excited about a BT30 taper for the Tormach.

Just some more thoughts and opinions.

Phil

PS: I bought and ran a non CNCed RF40 clone with an INT30 spindle for 9 years. I bought it for the "rigidity" reason being put forward in this thread. My conclusion after 9 years was that overall it was a pita for no discernable benefit.

I disagree.
For a parallel dia to assemble it must have clearance.
Thank you

[zephyr9900]

I'm having a hard time finding face mill heads that are aluminum specific.

redrider, the flycutter I'm using is the MM200 from Rotary Technologies ( http://www.rotarytech.com/category_listing.php?id=2 ) and it gives an almost mirror surface on aluminum (at least equal to the surface of some Mic-6 tooling plate that I have). I bought mine back in February when it was on sale for $31.45 plus shipping, but it is back up to the list price of $94.50.

It has a shank of .750, so it goes directly in the R8 collet. I plan to machine the body to provide a TTS-style seating ring so I can preset the height and use it in multi-tool programs, but for now I use it on its own to face stock (at 2900rpm and 29ipm per the datasheet! It really throws the chips.)

Best regards,

Randy

[philbur]

The inserts looks expensive at USD 21.25 a pop.

Phil

redrider, the flycutter I'm using is the MM200 from Rotary Technologies ( http://www.rotarytech.com/category_listing.php?id=2 ) and it gives an almost mirror surface on aluminum (at least equal to the surface of some Mic-6 tooling plate that I have). I bought mine back in February when it was on sale for $31.45 plus shipping, but it is back up to the list price of $94.50.

It has a shank of .750, so it goes directly in the R8 collet. I plan to machine the body to provide a TTS-style seating ring so I can preset the height and use it in multi-tool programs, but for now I use it on its own to face stock (at 2900rpm and 29ipm per the datasheet! It really throws the chips.)

Best regards,

Randy

[highspeedmazak]

What are you trying to do here? The R-8 is just fine except if you want faster tool changes then just go to the tormach tooling system or a Royal system and yes they both do great people underestimate the Royal system. We use both and some of our guys have put that Royal holder to the test IT WORKS. Save yourself some trouble, money and time if you are just working in aluminum then come on that is one of the easyest materials to machine you might just have a BAD facemill?