Broach Tooling lathe and mill workpiece advice

Broach Tooling lathe and mill workpiece advice

CNC Broach Tools recently had a client call us for advice about a internal keyway he was cutting on his mill. He had been using our keyway cutter for a couple of days straight and everything was working great but then without changing anything suddenly he started hearing a noise every time our broach tooling hit the part and his keyway had divets and a poor finish.

Being an experienced user of our keyway cutters he checked everything we usually suggest and still was having problems. After several conversations with me, both of us were frustrated as nothing had changed in his set-up. It was a mystery, what had changed?

Chatter just doesn’t magically happen. It’s always a result of something being loose.

99% of the time when clients call me for chatter/finish related issues the problem lies in how they are holding our tool. The other 1% of the time there is a machine issue. I learned something in this exchange about how machine issues can randomly creep in the broaching process.

The problem turned out to be 3 bolts that held the indexing table to the chuck. They each needed a 1/2 turn. Problem solved! How could CNC Broach know to suggest that?

So if you are getting chatter your clues will be the corners of the insert will chip and you will “hear it hit”. You will hear something moving.

  1. always check how you are holding our keyway cutter

  2. check how you are holding the holder that is holding our holder. (read that a couple of times and it’ll make sense) Whether it is a collet or boring bar sleeve that is holding our broach tooling, that is being held and can move as well.

  3. Then check your workpiece

  4. For mill broaching check the bolts holding your indexing table/chuck

  5. for lathe broaching tighten your ball screws

But 100% of broach tooling users want to blame the keyway cutter! 🙂 of course! that’s the easy way,

CNC Broach knows the problem is never our keyway cutter as our design does not change. We do not walk into the shop, create a one-off design with never before tested dimensions, and send it to somebody interested in our broach tooling. We take a standardized item off the shelf that 3000 other shops around the world are using and send it to you. And these other people are getting great results.

So if you have a problem. Look in the mirror, check your set up then your machine. Then call CNC Broach for advice. We’re always happy to help and are very good at providing clues and steering the operator toward finding the problem.

But do not suggest your problem is the broach tooling. It is like going to the hardware store, buying a hammer, and then calling the hardware store to complain when you hit your thumb.

  • It isn’t the grade of carbide.
  • It’s not the design of the keyway cutter
  • Nor is it the feed and speed that your running the broach tooling.

If the insert pulls out of the pocket, thank us!! we just saved your spindle! Inserts pull out of the pocket for 3 known reasons, :

  1. You do not have enough relief for your blind keyway
  2. you did not go far enough past the end of the keyway to allow for deceleration
  3. programming error and you stopped in the material at some point

CNC Broach created our keyway cutter design to protect your spindle. Our design is patented and has not changed since 2006 when it was sold through Razorform Tools.

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