Beveling an edge on a piece of plate

Discussion on all milling machines vertical & horizontal, including but not limited to Bridgeports, Hardinge, South Bend, Clausing, Van Norman, including imports.

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olddude
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Beveling an edge on a piece of plate

Post by olddude » Wed May 06, 2020 12:02 pm

I have an old Bridgeport that has a small table and it's all manual. I need to make some cutting blades for a machine I'm building and can never seem to get both sides to match. One side always seems to be shorter than the other. My other problem is that the plates are 22" and I only have about 14" of travel at best so I have to re-setup the plates to cut the full length. This presents another problem because I can never seem to get the part set back up so that it cuts on the same plane as the first cut.

I have been making the plates 11" and then welding the two pieces together which takes extra time. I know there has to be a solution to this but I just can't seem to figure it out. I can deal with the second problem but I would like to figure out how to get both side angles to come out the same so what is the secrete to cutting edges on a smaller mill table?

Russ Hanscom
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Re: Beveling an edge on a piece of plate

Post by Russ Hanscom » Wed May 06, 2020 12:28 pm

How about clamping a long stiff piece(s) of stock to the table, then you could loosen the work piece and slide it along the guides. If the guide is set up true, yo0u should only have to make one setup.

whateg0
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Re: Beveling an edge on a piece of plate

Post by whateg0 » Wed May 06, 2020 2:27 pm

Sounds like you need a sine plate! Or maybe you are nodding the head for the angle. So, maybe Russ is on the right track.

I don't know how wide your blades are, but I have machined a flat on a large round bar, then clamped the part to the round bar. The round bar can be put in the vise at any angle. I had to do that with the old mill/drill because the head didn't nod on it.

Dave

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warmstrong1955
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Re: Beveling an edge on a piece of plate

Post by warmstrong1955 » Wed May 06, 2020 2:42 pm

I use an angle table, with a block set up to position it and set it true to the world.
Do un to one side, flip it and Do the same (depth of cut) to the other.

Bill
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warmstrong1955
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Re: Beveling an edge on a piece of plate

Post by warmstrong1955 » Wed May 06, 2020 2:52 pm

This is a dull blade for a core splitter. (Mining stuff)
42.5 degrees.
Not a fancy set up, but it doesn't need to be.
Wouldn't be hard to make your own fixture, if you don't have an angle table. (That's what I did before I got the table)
100_1848.jpg
100_1849.jpg
Today's solutions are tomorrow's problems.

Harold_V
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Re: Beveling an edge on a piece of plate

Post by Harold_V » Wed May 06, 2020 3:25 pm

Hmmm. While I see multiple responses that allude to an angle being machined, you've not mentioned that is the case*. If not, you have an option that has not been addressed, one that permits machining the edge without moving the piece. Simply rotate the turret. That will work only if you aren't tilting or nodding the head, however. Rotating the turret will still work if an angle is involved, so long as the piece is mounted at the desired angle, so the head remains vertical.

When moving a piece on the table, you should be using a DTI to get the piece at the same attitude. The DTI is placed on the surface that was just machined, with the piece bumped around until it runs true. That way you can get a straight cut (as straight as a mill can provide, and you're at the mercy of the mill's condition). While you can rely on stops of some type, a DTI will ensure that the piece is set up correctly. When rotating the turret, you'll still have the issue of blending the two (or more) cuts, but that shouldn't result in a worse scenario than you get when you weld two pieces together. That's a sure recipe for misalignment.

I get the idea that your mill is not new, and may have severe wear. That may be a part of your problem in that a seriously worn machine allows the saddle to turn side to side. Doesn't take much movement to make things difficult for you. You can limit that movement by keeping the gibs as snug as you can, still allowing full travel.

H
*You did say both side angles. That's not clear. Are you making reference to angles being machined on the edge, or the angle between the edge and each side?
Wise people talk because they have something to say. Fools talk because they have to say something.

Russ Hanscom
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Re: Beveling an edge on a piece of plate

Post by Russ Hanscom » Wed May 06, 2020 6:29 pm

One more option, if you are making a flat cut and your machine will rotate the ram about the vertical axis. Start at one end, when you have gone as far as travel allows, back off the table some distance, swing the ram so the tool is now near the end of the cut, and continue. I used this method on my Gorton to cut a 28" flat with a table travel of 22", I was running a 4" face mill and needed enough travel for starting and stopping.

olddude
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Re: Beveling an edge on a piece of plate

Post by olddude » Thu May 07, 2020 9:28 am

Russ Hanscom wrote:
Wed May 06, 2020 12:28 pm
How about clamping a long stiff piece(s) of stock to the table, then you could loosen the work piece and slide it along the guides. If the guide is set up true, yo0u should only have to make one setup.
I like that idea. I had thought about doing something like this for another job one time and I don't know why I never tried it for this. Getting old I guess. :wink: Thinks for the tip.

olddude
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Re: Beveling an edge on a piece of plate

Post by olddude » Thu May 07, 2020 9:37 am

Russ Hanscom wrote:
Wed May 06, 2020 6:29 pm
One more option, if you are making a flat cut and your machine will rotate the ram about the vertical axis. Start at one end, when you have gone as far as travel allows, back off the table some distance, swing the ram so the tool is now near the end of the cut, and continue. I used this method on my Gorton to cut a 28" flat with a table travel of 22", I was running a 4" face mill and needed enough travel for starting and stopping.
I guess you are saying make the cuts with the Y axis?

Russ Hanscom
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Re: Beveling an edge on a piece of plate

Post by Russ Hanscom » Thu May 07, 2020 9:50 am

Yes

Russ Hanscom
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Re: Beveling an edge on a piece of plate

Post by Russ Hanscom » Thu May 07, 2020 9:52 am

Sorry, no, X axis, cutting side to side

olddude
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Re: Beveling an edge on a piece of plate

Post by olddude » Thu May 07, 2020 9:58 am

Harold_V wrote:
Wed May 06, 2020 3:25 pm
Hmmm. While I see multiple responses that allude to an angle being machined, you've not mentioned that is the case*. If not, you have an option that has not been addressed, one that permits machining the edge without moving the piece. Simply rotate the turret. That will work only if you aren't tilting or nodding the head, however. Rotating the turret will still work if an angle is involved, so long as the piece is mounted at the desired angle, so the head remains vertical.

When moving a piece on the table, you should be using a DTI to get the piece at the same attitude. The DTI is placed on the surface that was just machined, with the piece bumped around until it runs true. That way you can get a straight cut (as straight as a mill can provide, and you're at the mercy of the mill's condition). While you can rely on stops of some type, a DTI will ensure that the piece is set up correctly. When rotating the turret, you'll still have the issue of blending the two (or more) cuts, but that shouldn't result in a worse scenario than you get when you weld two pieces together. That's a sure recipe for misalignment.

I get the idea that your mill is not new, and may have severe wear. That may be a part of your problem in that a seriously worn machine allows the saddle to turn side to side. Doesn't take much movement to make things difficult for you. You can limit that movement by keeping the gibs as snug as you can, still allowing full travel.

H
*You did say both side angles. That's not clear. Are you making reference to angles being machined on the edge, or the angle between the edge and each side?
No this machine is not new it's almost as old as I am but it never saw much use. It was only used for two or three years in a machine shop and was put in storage because they went to larger machines when they moved to their new larger shop. Then CNC came about and they knew they were never going to need these old machines again so they donated some to schools around town and I had a friend there that got me a pretty good deal on this one so I bought it. That was close to 40 years ago and I had to keep it stored for most of that time because I didn't have a place to set it up. I finally got my home shop built and it is now set up in it's own spot. It had the old style table feed on it but something happened to a couple of the gears inside the unit and they don't seem to be all that easy to find any more so I took the motor unit off it to cut down on some weight and have been using it manually. For a machine this old it's not in bad shape. The head makes a little noise in the higher speed range but for what I do it should last me the rest of the time I have here on this earth. Hopefully that is. :)

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