How does HSK spindle drawbars work (for ATC spindles)?

[Goemon]

Do ATC HSK spindles use a draw bar like Cat 40 and ISO spindles?

I've been offered a deal on an HSK spindle cartridge but it doesn't have a tool clamp or automatic drawbar.

I can't find any aftermarket air powered or motorized drawbars or clamps for HSK A spindles on ebay (or anywhere else).

Is there a different name for drawbars for HSK spindles?

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[Algirdas]

Should be the same name - draw bar. Principle of clamping is very similar. Pullstud is "hooked" from outside in case of CAT and ISO toolholders. In case of HSK toolholder internal clamp is used.
Action of drawbar is pretty the same - the spring pulls drawbar back ( up ) with about 9 tons force clamping the tool. Activated hydraulics pushes the draw bar forward ( down ) releasing the toolholder.
Design of HSK

[Goemon]

Should be the same name - draw bar. Principle of clamping is very similar. Pullstud is "hooked" from outside in case of CAT and ISO toolholders. In case of HSK toolholder internal clamp is used.
Action of drawbar is pretty the same - the spring pulls drawbar back ( up ) with about 9 tons force clamping the tool. Activated hydraulics pushes the draw bar forward ( down ) releasing the toolholder.
Design of HSK

Thanks.

I guess I can't find any aftermarket air powered or motorized HSK draw bars because they either aren't made or aren't common then.

That's probably a good reason to avoid buying any HSK spindles unless they come with the draw bar mechanism.

I can't think of much benefit (to me) of using the manual HSK C clamps.

I'd consider repurposing an air or motorized drawbar from another type of spindle but the limited info I could find suggests that HSK spindles require way more clamping force.

Maybe with accurate specks I could make one with a suitably powerful pneumatic actuator but I'm not sure it warrants that level of effort.

[Algirdas]

Check the link I provided.
Never seen pneumatic or motorized draw bar. Pull force (spring force) for CAT or JSK or HSK is about 10 tons. Only hydraulics in my opinion.

an HSK spindle cartridge but it doesn't have a tool clamp or automatic drawbar

Who knows if you want a coolant-through and what kind you want. If you need air blow ( again through the drawbar ) or not. And what kind if yes. It just a spindle with HSK nose. All the rest is up to you.

[joeavaerage]

Hi,
HSK is just the 'cats pajamas' at high speeds, 30,000 rpm plus.

Craig

[mactec54]

Thanks.

I guess I can't find any aftermarket air powered or motorized HSK draw bars because they either aren't made or aren't common then.

That's probably a good reason to avoid buying any HSK spindles unless they come with the draw bar mechanism.

I can't think of much benefit (to me) of using the manual HSK C clamps.

I'd consider repurposing an air or motorized drawbar from another type of spindle but the limited info I could find suggests that HSK spindles require way more clamping force.

Maybe with accurate specks I could make one with a suitably powerful pneumatic actuator but I'm not sure it warrants that level of effort.

Do you have a Photo of the Nose of the spindle, as they have different styles of draw Bar assembles here are some snips that might give you an idea of what is needed, this is only ( 2 ) of the HSK designs, there are many more that are designed different, depending by who ever the spindle manufacturer is

TAC ROCKFORD may be able to help you with something

[mactec54]

Hi,
HSK is just the 'cats pajamas' at high speeds, 30,000 rpm plus.

Craig

At any speed

[joeavaerage]

Hi,
what size is the HSK interface that you are being offered?

HSK interface is covered by DIN69893, and that standard lists no fewer than nine different sizes from HSK25 through to HSK160. Even worse there are six forms,
A,B,C...F. All in all that is a lot of different combinations.

The good thing about standards is that there so many to choose from LOL

It seems that the most common size that is widely supported by manufacturers is HSK63, and the A,C and E forms are the most popular within that size.
What reading I have done suggests that the drawbar dimensions for a given size apply to all six forms....so that will reduce the hunt for a drawbar somewhat.

Craig

[Goemon]

I've been offered HSK 40 A and HSK 32A cartridges. I can't find any aftermarket HSK drawbars (new or used) of any kind though.

There's tons of new and used options for BT30, Cat 40 and R8 but I can't find a single listing for HSK ones on ebay, Amazon or any of the stores that sell auto drawbars for other tapers.

The only ones I've seen are as spare parts from VMC manufacturers (that offer an HSK option) but their prices are too high to be worth considering.

No point in getting a good deal on a spindle for a diy project if I'd have to spend thousands of dollars for the drawbar...