New Mill New User

[cartertool]

The design of the mill is that the backlash on the z-axis is taken up by the weight of the head and motor - so the gibs should be just loose enough that the head never has backlash. If the gibs are too tight then the head can jump under load.
You should end up if the gib (and don't overlook the two clamping "shoes" on the z-axis that hold it to the slide) - is adjusted correctly with .001 or less backlash in the z-axis.
While the backlash is mechanically there (you can push the head up by hand and have backlash), in operation there should be no backlash when moved by the stepper motor.

Originally Posted by impact I have finally got the gib smooth, the repeatability is perfect however I do have some backlash (about .005"). In theory if I am milling and I travel down, that means I have about .005" I have to worry about that I could go further down without wanting to? Or will the gibs hold it in place?

[impact]

I believe I am loosing steps in the x axis when I change direction under a load. Thanks for all your help so far.

[cartertool]

Originally Posted by impact I believe I am loosing steps in the x axis when I change direction under a load. Thanks for all your help so far.

It could be that the gib is too tight, it could be the weight of the workpiece (if you are mahcining a huge piece of steel), it could be lack of lubrication on the slides, it could have nothing to do with lost steps and instead be backlash - what is the current backlash on the x axis? It could be the old culprits of velocity, acceleration and pulsewidth as well..

What feedrate were you using on the x axis when you lost steps?

Now are you using the 140 oz/in steppers on x and y that Deepgroove sells? That alone could be your problem.

[impact]

Fixed.

I am currently using a flat bottomed table and now that my flood coolant system is finished and it is pumping quite alot of coolant up on the table I was wondering if there is any sort of commercial alternative to me fiberglassing up my table so it sll slopes to one place?

[impact]

I am looking for something to face with in aluminum that will fit in the 3/8 shank...

Also I want to do some 45° chamfers, being that inexpierienced in machining... do you need to get a specific chamfering tooling or can you use counter sinking bits?

[ViperTX]

impact.....well search for a face mill......if you can't find one then find an endmill that is 1" wide and has a 3/8 inch shaft......otherwise you'll spend your life facing with a 3/8 inch end mill.....

[impact]

Ive been looking haven't been able to find anything, I was wondering if anyone around has found anything they like.

[cartertool]

Harbor Freight makes flycutters with 3/8" shanks, but if you have access to a lathe it is very easy to make a flycutter.

For a face mill you would have to make a special shank, but again not rocket science.

A good tool grinder would be able to grind down the shank of any endmill, which would work for light facing - you can sometimes find 1/2" dia 3/8" shank endmills.

[phil burman]

Why do you need the shank to be 3/8". This is not a good technical solution for a face cutter due to reduce stiffness and therefore a reduction in the quality of surface finish.

Phil

Originally Posted by impact I am looking for something to face with in aluminum that will fit in the 3/8 shank... Also I want to do some 45° chamfers, being that inexpierienced in machining... do you need to get a specific chamfering tooling or can you use counter sinking bits?

[WhiteTiger]

If you're facing something like aluminum or plastic and are looking for a very smooth finish, I've always gotten good results on small parts by just regrinding by hand an old step shank endmill.

Knock back all but one flute to make a single point tool and then grind by eye a very shallow arc on the end face with the convex center near to but not right at the periphery. Hand stone the edge carefully, and you'll be amazed how mirror bright an aluminum surface can be.

I used an old 1/2" shank 3/4 endmill reworked in this fashion to cut a precision seven sided rotary aluminum mirror for a customer who was building some sort of optical lab prototype, and he was tickled to death with the level of surface finish.



Tiger

[WhiteTiger]

An afterthought: hss router bits are dirt cheap. Should be no problem doing the same with one of those, aside from having to hand grind a rake angle on the face (couple of minutes of dremel work), and 3/8 shank cutters with 3/4 diameter are easy to come by. They have the advantage of being pretty well balanced and beefy, unlike fly cutters.



Tiger