[How do I?] Make Hole 0.375" Larger Than My Largest Hole Saw

RegisG

Registered
Registered
Joined
Mar 25, 2016
Messages
65
I need a hole 2.875 in 1/2" crs near one end of part that will end up 5"x 5". I have a 2 1/2" hole saw but, that leaves me short. I have mill(PM-25MV) and lathe to work with. I have a DRO on my mill and "could" drill a lot of holes in a circle but, there must be a better way. I ruined the 1st one of these trying to use cheap rotary table that I had (returned it).
I'm guessing things like this will come up again and would appreciate any tips.

plate1.jpe

Thanks,
Regis
 
I would drill the largest hole using a drill bit. Say a 5/8" or 3/4" hole if your machine can handle it. Set you up a boring head and get after it, opening it up about .050-.075" at a time, or more if you mill/boring head will handle it. In about 15 minutes, you will have it out to 2-7/8". A lot quicker than using a hole saw. You could set up a trepanning tool and circle cut a slug out, never had any luck doing that.
 
I would drill the largest hole using a drill bit. Say a 5/8" or 3/4" hole if your machine can handle it. Set you up a boring head and get after it, opening it up about .050-.075" at a time, or more if you mill/boring head will handle it. In about 15 minutes, you will have it out to 2-7/8". A lot quicker than using a hole saw. You could set up a trepanning tool and circle cut a slug out, never had any luck doing that.

Well, now there is another tool I've never heard of and "should" have. Looked it up and some videos and it looks helpful. My next too priority though is a good rotary table.
Thanks for letting me know about a boring bar for mills.
Regis
 
If you have a faceplate for the lathe, you could bolt it on there, then drill out the center & bore out the hole to the right dimension.

It was practically designed for making round things.
 
A boring head will do the job nicely, If you are going to cut the longer bar off near 5" a 4 jaw chuck on your lathe will give you the same results. Getting "centered up" with respect to the edges may take some time in either case.
Have a good day!
Ray
 
Thanks for the help. I was hoping there was an easy way that I couldn't think of (with what I have). I really do need to take that 4 jaw out of the box and mount it. Got to learn it sometime!!

Thanks again,
Regis
 
I would cut it to the 5" square then put the 4 jaw on the lathe open the jaws up so it is lose use a dead or live center to hold it centered. then bring each jaws up to touch each side then tighten up. Then use the biggest drill you have or the hole saw to cut it out then bore to size.
 
I'm with kd4gij,use your 4 jaw and boring bar.like he said live center or dead center will get you in the ball park pretty fast. Bed time, going up to Lake Erie walleye fishing early tomorrow.
Thanks ron
 
I would use a boring head in the mill myself.
 
Back
Top