Bridgeport/cutting Question

FOMOGO said:
In addition to the advice in the posts above, if your stock is set up in the vise you might try clamping directly to the table to eliminate any issues (movement) with the vise. Welcome to the forum. Pretty tolerant bunch here, they put up with me. Mike
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Thanks Folks, I have another question. I just got a new 3/4 inch indexable carbide 2 flute cutter in the mail yesterday and since I destroyed the one I was using I have another question and a comment.

What speed would you run the carbide on cutting in 8620 steel and what depth of cut would you take.
 
I'd like to help with the carbide, but it's been probably 20 years since I had to figure Feeds and Speeds for carbide. I'd tell the machine, what the material was and what tooling I was using, and the computer would calculate the right numbers. Since I retired I'm using tiny little machines and high speed cutters. I'm sure others will chime in. Yes, a Bridgeport is a fine machine, but I look at all the joints/connections/places for movement between the tool and the work. It can't possibly absolutely rigid. Take light cuts and be happy. As a hobbyist, time is there to be spent.
 
Make sure your head tramming bolts are tight. The mill head might be getting pushed up, or the tool in the collet.
 
Thanks again to all who replied, I appreciate it. I'm using a valenite two fluted indexable carbide cutter, Is there a online site with charts and or a Calculator?
 
I usually use the same chart that is for HSS. Not using the carbide to it's full potential but safe.
The chart I have shows 300-600 rpm. I usually try something in the middle and adjust from there.
Would be nice if the 500 rpm worked then I wouldn't have to use low range.
 
Using carbon, you can run much faster spindle speeds. HSS shows 357 RPM but with Carbon shows 1375RPM with a .050" depth of cut.

Might want to consider getting the Machinist's hand book and/or a calculator like Machinist Calc Pro 2, which I have both the calculator and their app for IOS.
 
Andre said:
Make sure your head tramming bolts are tight. The mill head might be getting pushed up, or the tool in the collet.
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This is very critical. The 7 bolts in total are spec'd for 50 ft-lbs.
 
Have you checked all the ram bolts and table locks? It would be kind of tuff to move the head spindle bearings with out the machine growling loudly. May be the materials flexing , try smaller slower cuts .
Geez , forgot , WELCOME TO THE SITE , you won't be bullied here, if you do I'll quit it too.
No time for that kinda thing, life's to short to be that way.
 
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