Guys, I need a 10.85mm hole in 2mm aluminum to press-fit a F694zz bearing

Guys, I need a 10.85mm hole in 2mm aluminum to press-fit a F694zz bearing and have no idea how to obtain this hole size as long as drill bits are either 10 or 11 and maybe there are some specialized 10.5 (which i don’t have).

I am thinking about a few paths:

  1. scientific approach: heat the metal and drill hot with 11mm drill bit so that when contracting the hole gets to the desired dimension (is it even possible to calculate this?)
  2. use the non-perfect rotation of any drill bit that will result in a larger hole than intended due to wobbliness
  3. hammer the sucker in a 10mm hole (which will result in a tad larger hole (maybe 10.5mm) due to bit wobbliness.

Engineers out there, how should I approach this?

tapered ream

forgot to mention cheap method? :smiley: … this is a 1-time job and i’d have to buy the ream :-/

@Florian_Ford cheap? 10.5mm drill bit, small rats tail file, file then check with verniers. Repeat as nessecary?

P.s. Not an engineer. (obviously) :wink:

wiggle the 10mm drill bit around in the hole

That would be option 2) in the above list. I’ll surely resort to this unless I can do something smarter (and as cheap :slight_smile: )

Could I wrap some very fine and thin sandpaper arbound a 10mm rod clamped into the drill chuck? …hmmm :-/

0.15mm is going to be a brutal pressfit and nothing you’ll be able to properly fit without a real press. How about going with a 11.0mm bore and an adhesive? You can get specialized adhesives, similar to threadlock, that are made for this exact purpose.

27/64" drill is 10.71. I would start there.

@Thomas_Sanladerer That can work but for a one-time job seems unnecessary to buy the threadlock-like adhesive unless it is really threadlock :stuck_out_tongue: I can later use in other projects.

But in Europe those drills are hard to come by …I guess …I have never shopped for imperial units bits…

@Florian_Ford then use superglue, it’s the closest thing to a bearing adhesive and, depending on your application, might hold up just as well.

Reckon going with @Thomas_Sanladerer ​’s idea is a good one. Whilst you may only need the adhesive for this one job now, I can guarantee it’ll come in handy later, on the other hand, you could always make or buy a mount for your bearing then the hole could be whatever else you want.

I can get a 10.8 in the US. Metric is normally a bitch to shop for here.

Hmm you’re right, I can get a 10.8mm bit for around 3.6Eur + shipping so around 5Eur… who knew.
No hole in the pocket but useless bit after this.

@Florian_Ford ​ You can try using the thermal expansion trick as well with the 10.80 bit however when you look at the CTE for aluminum you’ll find it is very small. ~23um/m*°c.

@Mark_Rehorst I wish I thought of this before ordering them :slight_smile: well… I just have to find a way now.

Stepped drill bit?

All the methods mentioned by the people here are easy and fast and very ok for a 1-time-job. In the time you answered here again and again, you would have already finished any of the methods told :smiley:

I know. I’ll do that tomorrow though (not working on Sundays :slight_smile: ). + I wanted to pick a bit the brains of the engineers here which is a good way to learn.