Most Likely Metal

I've got some pretty specific needs for some of my machining. To that end I was modifying a screwless vise today to allow me to take advantage of the
full working envelope of one of my smaller machines. I started out just using Mach 3 wizards and seting it for "hard" steel. Snapped a 1/2" end mill like a small stick. So I picked up a roughing mill and ran nearly the same feeds. It did it, but I was getting a red hot curl instead of just chips. I backed off the feed and still got mostly chips, but I still got a blue curl pushing ahead of the mill. Then I decided I better pull out something better for speed and feed calculation. FS Wizard Lite on my phone. I plugged in 4140 as the material figuring it was a good starting point and it told me slower RPM and slower feed rate for about the same chip load. I got about 90% nice blue chips (no red glow) and 5-8% silver chips, and still had a small bue curl pushing ahead of the roughing mill. The cut itself looks pretty darn good for using a roughing mill. I did have to take the burrs off with a file and some rather heavy pressure. A deburring tool wouldn't touch the bigger ones at all.
Now I need to move the vise to the small high speed machine and finish cut in place. Its only a 2HP spindle, and its high speed (24K) so picking the right metal to plan the feeds to get that nice cut to alignment finish (with a smaller mill no less) may be kind of important. Its got no torque at all below 6K, and at 6K it doesn't have much.
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wrote:

It is often considered best to start with a slow speed and feed and work up rather than start at the top and work down :-)
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cheers,

John B.
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wrote:

Greetings Bob, My screwless vises are hardened steel. Pretty damned hard but not quite as hard as a file. So, I would advise using carbide cutters. Try 60 SFPM to start. That's only 916 RPM for a .250 dia. cutter. It may be your high speed spindle is just plain too speedy. Even a .125 cutter at 160 SFPM, which is probably too fast, works out to 4885 RPM. So try a .125 cutter at 7000 RPM and see how long it lasts. Your vise may not be as hard as mine. Eric
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They are pretty darn hard. I roughed off as much as I dared on the big mill. For what I want I need to finish in place. Fortunately I have a little mounting slop with my hold downs so I can push the vise front to back a little to minimize what I need to remove. I'll indicate the lower uncut face of course to minimize other issues with geometry, but the final top step needs to be cut to alignment and flat to travel after the vise is bolted down.
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The insert vises I own were ground very accurately square and parallel. Instead of modifying the vise could you mill a mild steel mounting pocket for it on a plate fitted and keyed to the machine?
Perhaps you can salvage the one you milled by surface-grinding?
--jsw
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That absolutely will not work. This is about being able to use the full working envelope of a small machine. Not about placing it accurately on the table. The ground face of the jaw was dialed in within about .0002-.0003 and its only that bad because that's about how flat it is. I've set enough vises now that only took me about five minutes. Half of that was getting set up. It 100% has to be milled/cut/ground to work as I want it for the application. Well I suppose I could have drilled and tapped (metal that hard... HA!) and added a removeable jaw to the back of the fixed jaw and the top of the moving jaw... Not likely. A larger vise will never ever fit without taking off the pretty cabinet enclosure, and it can't set back far enough on the table to work as is without hitting the column. I would really prefer to have used lockdown mill vises like I have on my big mill, but smaller ones (4 inch) are even longer than this screwless (8 inch) vise. They won't even think about fitting, and they have an even smaller clamping range. With this 8" vise with the jaws milled and the vise set properly on the table I can fully surface and machine stock that is 6" wide within its 6.6" maximum Y travel, and the vise fits inside the cabinet.
I've got 6" lockdown vises with aluminum soft jaws on my bigger mill (Hurco KMB1) and I love them, but there is no way anything big enough would fit in the cabinet on the smaller machines.
On this particular machine I did have an older 4" mill vise on it for a while, but it had the typical problem with jaw lift found on many modest price mill vises. I got tired of smacking my light weight high speed machine with a mallet, and it just barely fit in the cabinet.
I know this group tries to help sometimes by saying what we are doing is wrong. Sometimes what we are doing is wrong, but sometimes what we are doing is one of the only answers to the problem. I actually have another solution. On a similar machine ( I have three of them ) I made an aluminum "Infinity Vise" with Carr Lane hold down clamps on one side, and a fixed piece bolted to the table on the other side. I adjust it by moving the jaw with the CarrLane clamps and tightening the bolts that hold it to the table. It works pretty good. On the third machine I already have an 8" screwless vise with milled jaws. I haven't trued it in place. I just indicated to the surfaces I milled in it for another machine a few years ago. I hadn't figured it was going to be be my preferred solution for these machines, but it really surprised how me how easy it was to use compared to other solutions. My Infinity Vise won't work on the two machines (getting / with) the screwless vises due to minimum distance to the table. The one with the Inifinity Vise will probably get a cut 6" or an 8" screwless on it too because its so much easier to use.

Nothing wrong with it. No salvage needed. I just finished milling it with a 1/8" 4 flute at 6112 RPM and 9 IPM and a double blast of flood coolant. Its not a mirror finish, but its a better than brushed finish. Took very light cuts. Left a step, and then cut a channel behind it to eliminate any corner rounding being a problem in the step in the jaws.
I know it just jars your sensibilities to spend money on a precision ground vise and modify it, but there just isn't an off the shelf vise that will do the job. Atleast not one I could find. I either make a vise or modify one. I value my time, so modifying one was the best solution for me. Besides I still don't have a surface grinder.
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wrote:

From what I've seen surface grinders can be had cheap. I sold an old mechanical feed 8 x 24 for $400 and bought a beautiful 8 x 24 B & S Micromaster for $2000. I've seen hand feed 5 x 10 go for under $100.
Remove 333 to reply. Randy
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I keep looking at them. Just haven't pulled the trigger yet. I may need one eventually for some hybrid machine builds I've been working on for a while, but so far I am still trying to to work out off the shelf and machine to fit solutions to the problems.
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wrote:

One of the great things about having metalworking tools is that custom tooling can be made. I have modified all sorts of store bought tooling for use in the shop, as have all machinists. And every machinist I know has made tooling that allows the machine to be used beyond its designed capabilities. Eric
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P.S. Jim, I didn't mean that to sound harsh or unappreciative. I do appreciate your feedback. Its just that it wasn't the feedback I needed for the application this time around.
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