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


Tiny dovetail

Tiny dovetail

Tiny dovetail

We're machining a dovetail onto a set of mass-produced small aluminum (6061-T651) parts. It is a 60° dovetail, 5.5mm [.216in] wide x 1.25mm [.049in] deep.

The original plan to CNC mill the dovetail seems a no-go. The tolerance is ±0.05mm, which is way too much to maintain a decent sliding fit at that small size. At LMC, parts may even disengage and fall apart. Sliding fit tolerances for a Ø3mm hole are in the range of ±0.02mm.

Is it possible to reach these tolerances with a CNC mill? It is a high-volume production part, so they are not in a hurry to do something more exotic. But, it seems we need something better.

RE: Tiny dovetail

Does the dovetail go all the way through the part? If so then I think it could easily be fineblanked. There is up front tooling cost but with high volume that is easy to recover. Much cheaper than CNC. Depending on other features, you may need to finish the part on CNC.


The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

RE: Tiny dovetail

Blind dovetail (for now).

RE: Tiny dovetail

What you have described is not a particularly difficult operation for a decent CNC shop. These kinds of dovetails are produced by instrument manufacturers (think dial indicator mounts) in high volume on a relatively economical basis.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

RE: Tiny dovetail

Small broach, perhaps..?

Proud Member of the Reality-Based Community..

To the Toolmaker, your nice little cartoon drawing of your glass looks cool, but your solid model sucks. Do you want me to fix it, or are you going to take all week to get it back to me so I can get some work done?

RE: Tiny dovetail

I like the notion of instrument makers doing it. Sets a nice precedent.

I have limited power in this situation. The manufacturer is a client; I am a contract designer.

RE: Tiny dovetail



Note that the pictured product comprises two _arcuate_ dovetails,
in about the size you want,
with their rotation axes at right angles
and intersecting.

They make straight dovetails, too, and their stuff is not as expensive as you might imagine.

You might order a few pieces just to get some design/ assembly/ construction hints and to get a hands-on feel for what they can do.

Mike Halloran
Pembroke Pines, FL, USA

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! Already a Member? Login


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