Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here


Very simple for special tool expert on cast iron ...

Very simple for special tool expert on cast iron ...

Very simple for special tool expert on cast iron ...


thank you for entering in my post

This is a first time for me in this forum, my name is Paolo I'm working as CNC machinist for a company of 500 employees in England

I'd like to share with you my idea regarding a tool which should speed the production

I want to mount at end of a 31.5 couter bore tool a 8.5 drill.
I should make a 10mm hole at the end of the 31.5 couter bore tool to put the 8.5 drill in, a M8 hole for a grub screw and a hole in the back for internal coolant, plus we need to make a flat superfice on the side of our 8.5 drill for a grub screw
The cost of 8.5 drill is £135.00 already, How much is it going to be with a flat superfice for a grub screw?

I saw between the tips of the 31.5 counter bore tool we have 11mm of space that is exactly what we need to make a hole for our 8.5 drill, so for this reason it doesn't look a proper special tool, I don't think it should be as expencive as a proper special tool

How much could the price be for this tool on cast iron?

I saw I can mount this new tool on 4 cnc millings and the manager told me that I have to guarantee at least 30mins of saving time to get my idea going forward, and I believe in 24 hours if my tool doesn't break (our cast iron is a very bastard material) I could guarantee also more than 30mins

any suggestion will be very appreciated

thank you in advance for your help

RE: Very simple for special tool expert on cast iron ...

Hello Paolo, welcome to Eng-Tips!

I have a couple of questions for you. What is the application for this tool? Are you just using it to predrill the hole with the 8.5 and complete it with the 31.5 or is it for a 8.5 hole with a 31.5CB? How well does your shop adhear to feeds and speed requirements?
One of the biggest issues I always run into with custom tooling is that the long term cost doesn't usually improve the bottom line.


RE: Very simple for special tool expert on cast iron ...

Could you make a sketch? It's always easier if you have something to look at.

NX with Teamcenter 8 on win7 64
Intel Xeon @3.2GHz
Nvidia Quadro 2000

RE: Very simple for special tool expert on cast iron ...

Thank you Boottmills and Walterke for your help

The 8.5 drill needs to make a M10 tapping hole and the 31.5 couter bore tool makes just a recess on a 20mm pre-hole made by a previous step, that's why we could get into this 20mm pre-hole with the couter bore tool mouted with 8.5 drill, because we have this 20mm pre-hole

I left some pictures about the tools

thank you for you availability

RE: Very simple for special tool expert on cast iron ...

You are asking for a step tool with a 8.5mm dia drill with a counterbore of 31.5. Making a high speed steel tool is very simple however if you want an inserted c'bore there becomes a problem with the insert width. It would take a custom width insert to allow the clearance for the 8.5mm drill. the cutting edge of the insert would have to be 11.5mm wide and be insertable. If your volume justifies the cost of the tool then there is no problem.

Use of custom tools in the past was relatively common but as the CNC machines with tool changers became the norm avoidance of special tools became more of the norm. The exception is the cutting of hyraulic ports they still use multi-diameter cutters with specialized chamfers for seals.

It's all based on costs.

Good Luck,

RE: Very simple for special tool expert on cast iron ...


Thank you so much Bill for your reply

may you please also have a look at my new thread it's about a jig very interesting topic too

thank you so much again


Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close