Hexagonal Hole Drilling- Watts type?

[tomcannon]

Hi, after some research online, the Watts process of drilling hexagonal holes would work for me, I need to drill 5mm size holes across flats, 4mm deep in EN24 steel bars.

The problem for me is the setting up of having to put the guide plate on every time. Is there a more efficient way, or a way of fixing the guide plate to the tool holder so it can be used on a CNC turret lathe without having to interfere so much?

 

[benta]

Try looking at rotary broaches. No guide needed.

Benta.

 

[tomcannon]

Ah, the rotary broach uses an out of square holder to cut at an angle does it not? I had heard of the process but was unsure of the name, I'm in the UK so harder to find as much relevant information but will keep looking!

 

[gaufridus]

Rotary broaching (also called wobble broaching in the UK) is readily accessible in the UK. We have some special screws made with hex recesses. I can't remember at the moment who the sub contract company is and I am not in contact with the office for the next couple of weeks. I tracked the company down by ringing the manufacturers of the tooling. Try Google.

 

[tomcannon]

Yep thanks guys, I found 2 or 3 companies and have been emailed back by all with prices which for reference are all cheaper then Watts type tooling and the benefit for me is that you do not need a guide at all. Tool life is unknown to me as I have used neither but it should not be an issue.

Thanks for the info,
TC

 

[unclesyd]

Depending on the quantity, you may want to drill a proper size hole a little deeper than required for the hex and use a stubby hex broach like the ones used for rotary broaching. to form the hole.

http://hassaysavagecompany.stage.thomasnet-navigator.com/category/rotary-punch-broaches?

 

[hexalobe]

Also, can you pilot drill oversize? This extends broach life and reduces pressure on the machine.

http://www.youtube.com/watch?v=2zEz9CSoA3s