Help with trouble shooting my bridgeport mill

BossIndJay · Oct 3, 2018

Im atill a beginner by all means! Just got a job at a shop that has old machinery. Im having trouble woth cutting my keyways on my mill though! Ive swept in my vice and everything but my keyway cuts are riding off to the side. Can anyone lead me in the direction of finding and fixing my problem because i am the only machinist in this whole shop

Dumpster_diving · Oct 3, 2018

Maybe backlash in the axis you're cutting along is allowing the cutter to push the part (and the table) off in one direction due to tool pressure?

Have you locked down the axis you're not traversing during the cut?

Just one possibility.

kenton · Oct 3, 2018

Are the 2 bolts holding the ram (on the right back side of the machine) tight. I had all kind of weird things happening one time until I realized that someone had loosened them.

Bill D · Oct 3, 2018

Are you taking to deep a cut and trying to cut the slot in one pass?

eKretz · Oct 3, 2018

Don't try to cut keyways with an on-size endmill in one go. Use a smaller one to rough out the keyway, then either move it side to side and make passes to finish size (generally preferred if you want properly straight and correctly sized keyways) or swap for an on-size endmill and run it down the roughed out keyway.

jccaclimber · Oct 3, 2018

Lower likelihood, but sweep your part or vise jaw with the part clamped in. I stumbled across a vise cracked at the fixed jaw key on a BP several years ago. The vise indicated fine open, but the fixed jaw would bend back on one side when something was clamped near the top. Shop manager insisted that it wasn't fully broken and therefore didn't need to be replaced.

JohnEvans · Oct 3, 2018

And what are you using for a cutter? 2 flute works the best. And as said lock all axis not in use including the quill if it is retracked.

redlee · Oct 3, 2018

How are you holding the endmill ?

RODELU · Oct 4, 2018

I use a very old worn-out Bridgeport to cut my keyways, mostly 3/16ths wide and as long as needed using a 3/16th wide woodruff cutter. This may or may not work for you depending on the size of the keyways you cut and on the diameter of the shaft.

DMF_TomB · Oct 4, 2018

most rough out keyway 1/64 to 1/32 small and then take a finish cut. all cutters deflect under load. usually dont use a 1/4" end mill to cut a 1/4" keyway or if you do you finish taking a very small amount

JRIowa · Oct 4, 2018

I know that this will come as a surprise, but there is a Bridgeport forum.
Pictures. There are so many things that you could be doing wrong, with out pictures or being there, everybody is just guessing.
JR

awake · Oct 5, 2018

I'm sorry you are having trouble shooting your Bridgeport, but honestly, it is not that hard - just point the gun and pull the trigger!

(Don't you just love helpful answers like these??)

Spinit · Oct 5, 2018

Check your vise and make sure it has zero indicator runout on immovable jaw and be sure to tighten the vise down good sonyour vise does not move. I assume your head moving forward and backward tilt is secured from moving as is the nuts on the boom and swivel. Also on your head rotation left to right on x axis.

Be sure your bed ways are not severely worn as they can move. For this some people snug the bolts which secure movement on the x and y axis snug it to drag making it tighter. If you are slotting in the X direction lock your way saddle in Y tight to not move.

get a solid tool holder if you can and lock your quill so it does not move. Feed into the slot at a shallower depth to see what happens before going to depth. Also use first a scrap piece of comparable steel and cut that rather than a finished shaft to avoid scrap.

test it out first on raw material not finished lathe parts.

hope this helps.

Trboatworks · Oct 5, 2018

Are you closing your eyes when you pull the trigger?

thermite · Oct 5, 2018

Trboatworks said:
Are you closing your eyes when you pull the trigger?

If he was not "warned off" by the Bridgeport brand? Surely had to have had his eyes wide-shut!

Richard King · Oct 5, 2018

I private messaged this newcomer to listen to JR who is a very good Moderator IMHO.

also found this for him. CUTTING A STRAIGHT KEYWAY with BRIDGEPORT MILL tubalcain - YouTube

You smart Alecks need to remember you were once new to the trade and had to write your first post here. He came to ask us for help not get a bad time.

thermite · Oct 5, 2018

Richard King said:
I private messaged this newcomer to listen to JR who is a very good Moderator IMHO.

also found this for him. CUTTING A STRAIGHT KEYWAY with BRIDGEPORT MILL tubalcain - YouTube

You smart Alecks need to remember you were once new to the trade and had to write your first post here. He came to ask us for help not get a bad time.

Yah well.. crusty Old Farts may have hurt my sensitive feelings when I was a youngster and still owned any such of a thing.

But the MONEY they saved and years of life not wasted was one Helluva useful PAYBACK for it.

His own situation. His own call. His own "due diligence" what or whom to pay attention to.

Or not.

No "bad time" involved. Just different experiences, shared-out. In PUBLIC, even.

Not "back-doored".

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Help with trouble shooting my bridgeport mill

BossIndJay

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kenton

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Bill D

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eKretz

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jccaclimber

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JohnEvans

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redlee

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RODELU

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DMF_TomB

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JRIowa

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awake

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Spinit

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Trboatworks

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thermite

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Richard King

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