CAT40 Pull Studs and Retention Knobs

Pull studs (retention knobs), stocked in Canada. The drawbar needs something to grab — one per holder, not supplied with the holder.

The taper does not tell you which one you need. Both of our CAT40 studs are 45° knob, 5/8"-11 thread — identical on paper. They differ in length, and length is set by the machine builder. A standard-length stud will not work correctly in a spindle that wants the short one.

Pick by machine:

HAAS, CAT40 MAZAK, CAT40 HISION, CAT40 Ask us on WhatsApp

Another machine? Send us the model and we will tell you which stud it takes.

Total found: 3

Only new

Only in stock

CAT40 (CT40) Pull Stud, 45° knob, 5/8"-11 thread

PST40i5811In stock

CA$10.61

excl. taxes

CAT40 (CT40) Pull Stud, 45° knob, 5/8"-11 thread, short

PST40i5811SMade to order

CA$10.44

excl. taxes

SK40 (DIN69871) Pull Stud, 45° knob, M16x2.0 thread, 10 pcs

217-22323SETArchive

Pull Studs (Retention Knobs)

A pull stud screws into the back of a taper holder and gives the drawbar something to grab. Without it the holder will not stay in the spindle. It does not come fitted, and it is not included with the holder — you order one per holder.

The taper is not enough to pick one

This is where the mistake happens. Both of our CAT40 studs are 45° knob, 5/8"-11 thread — identical on paper. They differ in length, and length is set by the machine builder, not by the taper standard.

Standard length — what HAAS CAT40 mills take.
Short — what Mazak and Hision CAT40 mills take. A standard-length stud will not work correctly in those spindles.

So "I need a CAT40 pull stud" is not enough information to order. Check the machine's spindle specification, or tell us the machine and we will look it up. Two mills with the same taper on the badge can want different studs.

Why the material matters

A pull stud is a small part carrying a large load. The drawbar holds it in tension every second the tool is in the spindle, and that load cycles with every tool change. It is a fatigue part, and fatigue parts fail without warning.

When one lets go, the holder comes out of the spindle at full rpm. That is a broken tool, a scrapped part and a damaged spindle taper on a good day. It is not the place to save two dollars, and it is the reason a stud that has been in service for years is worth replacing rather than reusing on a new holder.

Fitting them

One stud per holder, and they are sold in multiples of ten because that is how shops actually buy them — a holder without a stud is a holder you cannot use.

Torque them to the holder manufacturer's figure and check them periodically. A stud that has worked loose is the same failure as a stud that has broken, arriving more slowly.

Keep the thread and the seat clean. A stud that is not seated square sits off centre in the drawbar and adds runout to every tool in that holder.

Buying Pull Studs from CNCmarket

Prices and stock are on every product page and you can order online without waiting for a quote. Delivery is free across Alberta and we ship anywhere in Canada.

We run our own machine shop in Calgary and use these ourselves. If you are not sure which length your spindle takes, tell us the machine — that is a five-minute question for us and an expensive guess for you.

Frequently Asked Questions

The taper is not enough to pick one

Standard length — what HAAS CAT40 mills take.

Short — what Mazak and Hision CAT40 mills take. A standard-length stud will not work correctly in those spindles.

Why the material matters

Fitting them

One stud per holder, and they are sold in multiples of ten because that is how shops actually buy them — a holder without a stud is a holder you cannot use.

Torque them to the holder manufacturer's figure and check them periodically. A stud that has worked loose is the same failure as a stud that has broken, arriving more slowly.

Keep the thread and the seat clean. A stud that is not seated square sits off centre in the drawbar and adds runout to every tool in that holder.

Buying Pull Studs from CNCmarket

Prices and stock are on every product page and you can order online without waiting for a quote. Delivery is free across Alberta and we ship anywhere in Canada.

Pull Studs for VMC

Pull Studs (Retention Knobs)

The taper is not enough to pick one

Why the material matters

Fitting them

Buying Pull Studs from CNCmarket

Frequently Asked Questions

Pull Studs (Retention Knobs)

The taper is not enough to pick one

Why the material matters

Fitting them

Buying Pull Studs from CNCmarket

Frequently Asked Questions