Undercut Holes - Is This Possible to Machine? 7

[jwickham]

On a part I am trying to design, it would be very convenient to add a couple of undercut holes, but I am not sure there is enough room to machine them (see the screen shot in the attached link). There is 2.35" between the face the holes are drilled in and the fins. There is .730" between the edges of the holes and the side walls.

Is this possible with standard machining techniques?

 

[KENAT]

Almost anything is possible for enough money. However, can you allow access holes to maybe make it easier? See attached.

forum281 might be worth a look if you don't get the answer you need here.

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[ornerynorsk]

What Kenat has suggested is a good solution, if it is allowable in the design. In the drilling of coolant channels for mold and die cast tooling, and in hydraulic manifolds and valve blocks, oil galleys, etc, it is very common to drill access holes and then plug them during assembly.

 

[ivymike]

Mahle machines the undercrown area of pistons using a 90deg milling tool. It sneaks into a smaller gap than that and machines a profiled oil gallery. There are also 90deg drills, you may be able to find one with a short bit that'll fit. Either may be more expense than warranted, given the simpler method proposed above.

 

[ivymike]

oh, perhaps you could add an angled pad to the crossmember you're drilling, and drill at a slight angle?

 

[jwickham]

I like the idea of drilling the access holes. There is another component that is epoxied on during the assembly process, so it would be easy to fill the holes at the same time. The idea of a slot had briefly crossed my mind, but the access holes leave more material around the crossmember holes, which is helpful since the material is fairly thin in the middle.

Thanks everyone!

 

[MikeHalloran]

Or, you could use a small ball-end mill and cut slots from the near/top side.



Mike Halloran
Pembroke Pines, FL, USA

 

[mfgenggear]

an other suggestion would be!

if space permits

it is possible to make a drill jig & drill with a "90 deg"right angle aircraft style drill attachment.

http://www.tightfittools.com/tigfitdrilki2.html

MfgEngGear

 

[loughnane]

If they are just clearance holes (and don't need to be tapped), you could borrow a page from injection molding and create a kind of shutoff hole.

Double the thickness of the rib, mill from the top and bottom.

something like this....

http://www.protomold.com/Design_Tips/UnitedStates/2003/2003-11_designtips/throughholes.jpg

It's a hack, but a cheap way to get a clearance hole.

Chris Loughnane - Product Design

http://www.pdnotebook.com

http://www.twitter.com/DesignNotebook

 

[petman]

loughnane is on the money

petman