How To Make A Flat Bottom Hole
#1
Question 
What's the best way to make the flat bottom hole as shown in the sketch below? It's the 1/4" x 3/4" hole that needs to be flat.

Thanks,
Ed

   
Reply
Thanks given by:
#2
What the heck are you building ?
sasquatch, proud to be a member of MetalworkingFun since Jul 2012.
Reply
Thanks given by:
#3
I'd like to see that too, maybe a plug pressed in from the left or pre-drill and grind up a drill bit for a couple of guesses. Luck out and find a counterbore that would fit? This one is $25.

http://www.travers.com/product.asp?eapro...%2F4%22%27
Reply
Thanks given by:
#4
endmill
dallen, proud to be a member of MetalworkingFun Forum since Apr 2012.

If life seems normal, your not going fast enough! Tongue
Reply
Thanks given by:
#5
(12-13-2012, 08:30 AM)Sunset Machine Wrote: Luck out and find a counterbore that would fit?

I was also thinking of a counterbore but haven't taken the time to look for one. It might be my best option.

Ed
Reply
Thanks given by:
#6
(12-13-2012, 08:46 AM)dallen Wrote: endmill

I'd be concerned that the end mill would grab the part and tear it out of the vise. The material is aluminum which gets kind of grumpy when trying to do a plunge cut like that. I'd probably end up snapping off the 1/4" end mill and not only ruin the end mill but the part and my day.

Ed
Reply
Thanks given by:
#7
I'm making a work stop for my mill vise.

Ed

   
Reply
Thanks given by:
#8
(12-13-2012, 09:23 AM)EdK Wrote:
(12-13-2012, 08:46 AM)dallen Wrote: endmill

I'd be concerned that the end mill would grab the part and tear it out of the vise. The material is aluminum which gets kind of grumpy when trying to do a plunge cut like that. I'd probably end up snapping off the 1/4" end mill and not only ruin the end mill but the part and my day.

Ed

Drill it out (about 7/32" diameter), and get close to depth. The end mill is just for the finish cut. Much less wandering, grabbing and chattering. Of course, you need to peck it, just like drilling. Use WD-40 liberally as lube for better finish and less buildup on the mill.
Full of ideas, but slow to produce parts
Reply
Thanks given by:
#9
I wouldn't hesitate to do that with an end mill. Two flute if it was a blind hole, but you can drill through with the 0.17 then ream with a 2 or 4 flute. Can't see that coming out of the vice.
Free advice is worth exactly what you payed for it.
Greg
Reply
Thanks given by:
#10
the way that's drawn, looks like to me that only one side of the clamp is going to actually do any clamping, or am I missing something. ?
dallen, proud to be a member of MetalworkingFun Forum since Apr 2012.

If life seems normal, your not going fast enough! Tongue
Reply
Thanks given by:




Users browsing this thread: 9 Guest(s)