Super Noob question. First time milling

[higgite]

Like others, I’m not exactly sure what it is that you’re doing. A photo of the work piece orientation in the vise and telling us the actual depth of cut and width of cut might be helpful to help you analyze the problem.

Tom

Edit: After seeing post #14, I have pared my original response down to the only part that turned out to be useful.

 

[markba633csi]

I trick I use when holding uneven pieces in the vise is to use a popsicle stick between the part and one jaw; it squishes and takes up the gap.
Use good quality USA made end mills. Many of the import ones dull very quickly. Use cutting fluid and slow speed for steel.
Sometimes you can find amazing deals on new/used endmill lots on Ebay- I've gotten many a good bargain there
Mark

 

[benmychree]

Another cure for work lifting off the paralells is the use of vise hold downs, available from Starrett and others, they work well for work with work that is held with the wide dimension horizontal, for work with the narrow side up, I use a piece of round bar between the movable jaw and the work.

 

[Threadkiller]

Man you guys are awesome. Sorry for the long paragraph. I was exhausted and just rambling on.

I’ve attached a picture of my setup. You could see the angle in the picture. As far as the speed I’m not sure what the machine is at. It’s not at a super high rpm. I have to check.

The work piece is 1”thick flat bar.

I was using rapid tap cutting oil.

 

[mikey]

Okay, now its clear what you're doing and why you're having problems. Here are some comments:

• Not so sure if that vise is all that accurate. The Angle Lock design is better in that the moving jaw pushes the part down instead of allowing to rock up. You might look into a better vise.
• The edges of your work piece are very rough and uneven. You need to square the whole thing up before it will sit flush to the jaws and parallels, then you can take cuts that will be flat enough to measure. Do you know how to square a part?

 

[ThinWoodsman]

Not so sure if that vise is all that accurate.

That looks like the bridgeport vise that came with my mill. Perhaps not optimal, but suitable enough for learning. I had to make new jaws for mine though, as the old ones were pretty chewed up. Finally replace it with a Kurt, which I will agree is a huge improvement - but I wouldn't dismiss the old vise out of hand.

 

[RobertB]

That looks like the bridgeport vise that came with my mill.

It's similar to a Bridgeport, but the Bridgeport has a "rounded rectangle" base that sits atop the swivel not the round lobes this one has. It also appears to be missing a jaw. You are correct that it can be made to work, it just takes more care and finesse to ensure the work remains tight to the parallels. I would also remove the swivel base and attach it directly to the table and use larger diameter bolts than the ones currently holding it to the table. (the ones holding the vise to the swivel base look to be the correct size)

 

[mikey]

... I wouldn't dismiss the old vise out of hand.

I wasn't dismissing it out of hand. I was pointing out that vises like this that have a horizontal linear push from the screw can, and usually do, push a part up as pressure is applied. This is especially true if the edges of the part that contact the jaws are not flat and square as is the case here. Quite often, you can pound a part down onto the parallels with a hammer in a vise like this and one of the parallels will still slip. I am not guessing about this but perhaps your experiences differs. If so, do tell.

 

[Mitch Alsup]

a) did you make sure the vise is "in tram"--not just the back jaw face, but also the back jaw top and the inner vise "ways" where the parallels rest. Any errors here will show up directly on the part, after machining. Is the spindle tram to the table? both directions? I had to disassembly my vise and clean it within an inch of its life to get the vise to tram square.
b) you need to file the burrs from sawing off the part before installing it in the jaws of the vise--so the part can rest on the parallels and be evenly clamped by the vise. Burrs may not allow the part to rest on the parallels, or to be evenly clamped on the faces of jaws.
c) after clamping the part in the vaise, hit it on the top with a hammer (several places) to seat the part and the jaws to the ways of the vise. You can get 1-3 thou of rise just clamping a part in the jaws.
d) you can measure the flatness of the part in the jaws after clamping with the DI in the spindle.
e) as a part comes out of the saw, none of the sides are flat enough to be accurately machined. So, we square up the part by machining one surface, then square up the other sides by using the first machined surface as a reference in the back jaw or on the ways of the vise. In effect, we machine the part to square, and only then machine the part to what we want.

 

[Threadkiller]

Thank you all again for taking the time to help me with this. Sorry for the delayed response. Its been a very busy holiday weekend. I hope everyone had a great one.

It's possible that your work lifts in the vise. The amount being 0.015" would be a LOT. Use an indicator and verify the amount of lift. More than a couple of thou would be more than I would like. Tap it down with a dead blow hammer with a soft face. The parallels should be snug. Make sure you clamp in the center of the vise.

Look for some videos on squaring material. Using the mill finish as a reference is going to lead to bad parts. There are no guarantees that the surfaces are even close to straight. Making a block square to 0.005" or better is a great exercise for learning setups and cutting. It is also where many projects start.

Ive watched a couple of videos on squaring material but it was before I had a milling machine. I will have to watch them again and try it myself. I also have tap the part. Ive seen many youtube machinists do it but honestly I did not remember to do so.

Holding hot rolled flat bar can be an adventure. It frequently is not flat across the wide side, being somewhat "cupped" and the edges are not square to the flats. This makes it move as you are clamping it down, As the others have pointed out, snug your vise up but don't crank down on it, tap the part down against the parallels with a hammer, tighten the vise firmly and then see if you can move your parallels. If they are loose repeat the above steps until the part is tight against them.

I will try that thank you!

I trick I use when holding uneven pieces in the vise is to use a popsicle stick between the part and one jaw; it squishes and takes up the gap.
Use good quality USA made end mills. Many of the import ones dull very quickly. Use cutting fluid and slow speed for steel.
Sometimes you can find amazing deals on new/used endmill lots on Ebay- I've gotten many a good bargain there
Mark

Mark, what do you mean by an uneven piece? Would you consider my work piece uneven? I am not sure how the popsicle stick would help anything can you elaborate? Thank you.

Okay, now its clear what you're doing and why you're having problems. Here are some comments:

• Not so sure if that vise is all that accurate. The Angle Lock design is better in that the moving jaw pushes the part down instead of allowing to rock up. You might look into a better vise.
• The edges of your work piece are very rough and uneven. You need to square the whole thing up before it will sit flush to the jaws and parallels, then you can take cuts that will be flat enough to measure. Do you know how to square a part?

Mikey, the vise has definitely seen better days. I just looked up angle lock vises and my jaw dropped ha. I knew Kurt was expensive but didnt think they were that expensive. I guess I shouldnt be surprised as everything in this realm thats quality is expensive. Gotta pay to play. Unfortunately money is a little tight at the moment especially for a $600 vise. I will have to keep my eyes on craiglist.

I have seen many videos on squaring a part but like I said previously they were all before I even had a milling machine so I didnt take it all in. I honestly thought I was squaring the piece. I was going to take a couple light cuts on one side and flip it over and do the same, then using the two flat surfaces as a reference i was going to square up the sides. I assume thats incorrect as it sounds too easy haha. I will look into squaring a part as I now remember it seemed more complicated than that.

That looks like the bridgeport vise that came with my mill. Perhaps not optimal, but suitable enough for learning. I had to make new jaws for mine though, as the old ones were pretty chewed up. Finally replace it with a Kurt, which I will agree is a huge improvement - but I wouldn't dismiss the old vise out of hand.

I figured its ok for learning but if its going to give me this many problems right outta the gate Im going to have to look into a new one.

It's similar to a Bridgeport, but the Bridgeport has a "rounded rectangle" base that sits atop the swivel not the round lobes this one has. It also appears to be missing a jaw. You are correct that it can be made to work, it just takes more care and finesse to ensure the work remains tight to the parallels. I would also remove the swivel base and attach it directly to the table and use larger diameter bolts than the ones currently holding it to the table. (the ones holding the vise to the swivel base look to be the correct size)

I actually was thinking about taking the swivel off just because I dont know if ill ever even use it and I need all the help I could get with removing variables ha.