Squaring Up Stock

[EmilioG]

I have a piece of annealed O1 flat ground tool steel for a project. I found the size I need, 7/8" thk. (fairly expensive).
It's 3" w x 8" long. I need to cut it to 3" x 3" square. It came .003" over the 3" side, so I can't square up that side.
How can I square two sides only, after I band saw the length to 3.5" or so? I can't touch the stock 3" side, only wet sand.
The top sides are Blanchard ground, so I will only sand/polish by hand. It's for a few finger plates. One is a gift ( I don't need 3 )

Can I just put longer ends on a piece of welding wire, the other side on a rod, indicate one side square and fly cut or mill, then flip it over?
I can only square up the ends.
This is interesting:

 

[Billh50]

Not sure why you are cutting the pieces 1/2" oversize or what tolerances are. But just put the piece in the vise and side mill one end. set a stop for the pieces and then mill the second side to size.

 

[RJSakowski]

By the 3" side, I am assuming you mean the long side.

Normally in squaring stock, you would start with one straight side, preferably the long side, indicate in the mill and mill the short side square. You do this to minimize stock removal. In your case the piece of O1 is probably ground flat, straight and parallel on the two long sides. It is also probably square to the top and bottom surfaces. If that is true, you can flip the piece afte4r milling the first short side and milling the remaining side to dimension. You should always keep one good side in contact with the fixed jaw which has previously been swept with an indicator and adjusted to be parallel to the ways.

Since you are working a 3" x 3" piece, you could mount vertically in the vise. You would then have to indicate the good vertical surface. That is a considerable extension over the4 height of the typical mill vise so some caution is advised.
I would prefer an end mill over the fly cutter on O1unless you can slow the spindle down enough.

If the long sides are not square and parallel, you will have to do those as well.

 

[EmilioG]

Not sure why you are cutting the pieces 1/2" oversize or what tolerances are. But just put the piece in the vise and side mill one end. set a stop for the pieces and then mill the second side to size.

I'm leaving about .50" for about 1/4" on each side to mill off/square. I'm leaving a little more than usual in case I make a mistake.
RJ: I can add an extra piece of flat plate against the stock to add rigidity, since it will stick up a bit more than I like.
The tolerances are not critical. I would like the piece to be 3" square, plus/minus .003" if I get lucky and take my time.
All depends on what shape this BP mill is in. (using work site mill). This is simple stuff, but I need to get it right the first time.
I don't have that much O1 flat ground tool steel to waste. I'll cut it to 3.25" and that should leave enough metal to square off.

Thank you Gentlemen.

 

[RJSakowski]

I agree with Bill that 3" is a lot of overage A cutoff saw is usually fairly good at cuttting true. I would find the shortest distance across (the corrner with the angle greater than 90º). I would then scribe a line a 1/8th inch more than the desired dimension for my cut line. A lot less work than trying to milll a 1/2" of O1. After you get to know your saw, you will be cutting tha down to a 1/16th.

 

[EmilioG]

Sounds good. 1/8" may be just about right. A lot less milling. The stock is 7/8" thick. I can use the extra to make something else.
A friend just gave me a box of Starrett A2 and O1 precision tool steel. Buying heat treating supplies. I have many hours of experimenting ahead. Thanks.

 

[EmilioG]

Also, I think I'll square the ends before I cut the longer piece on the band saw. This way, It will be easier to square the rest later.
The other problem is that one of the rough band saw cuts is way out of square and needs to be milled off. It's almost .240 at the highest.
It's not enough for the band saw.