Part is 34" maximum cut on my mill is 26"

madmodifier

Registered
Registered
Joined
Jan 7, 2014
Messages
113
So I am working on making some new gibb strips for a 1900's shaper I am getting working again. The problem I have is that I cannot cut the whole part in one setup. My vertical mill is very worn so I will be planning on scraping the important surface of the gibb strip to make sure it is true enough. How do other folks handle making cuts on very long parts?
.IMG_20181020_164458168_HDR[1].jpgIMG_20181020_184231820[1].jpg
 
Scraping it in is a time proven way to accomplish your task. Having a surface plate big enough that it will take the entire length of the gib will make things better and easier, but still can be done if it overhangs a bit, with some care. One of the beautiful things about scraping is that we do not need bigger machines to make accurate parts for our smaller machines.
 
One of the things you learn in Tool and Die making is transferring setups and/or measurements... It is a tedious and meticulous process! You mill as much as you can. You shift the work in the mill so you can finish the work. Then you indicate it in to tenths or better: you are usually indicating in say, 3", but making a (for example) 9" cut. Any error is going to be 3 times what you can see.

A friend of mine got so good at this he was transferring setups on insertion fixtures, and holding 2 tents over the entire surface, with 4 setups! These fixtures were 40" by 40". He was truly a master. Wit practice and patience, you can too!

P.S. On a worn mill you have to be twice as careful!
 
One of the things you learn in Tool and Die making is transferring setups and/or measurements... It is a tedious and meticulous process! You mill as much as you can. You shift the work in the mill so you can finish the work. Then you indicate it in to tenths or better: you are usually indicating in say, 3", but making a (for example) 9" cut. Any error is going to be 3 times what you can see.

A friend of mine got so good at this he was transferring setups on insertion fixtures, and holding 2 tents over the entire surface, with 4 setups! These fixtures were 40" by 40". He was truly a master. Wit practice and patience, you can too!

P.S. On a worn mill you have to be twice as careful!

Thanks! That is the only thing I could think of as well.
 
On your setup how are the ends held down?
Find which way your machine cuts more accurate. Your set up using the end of a endmill.
Or try taking the vice off. Use 123 blocks every 6-8 inches with hold down straps corresponding. Then side mill your max length loosen setup. Index the rest of your part and dial in of the surface you just milled. Your should be able to get as good as you can align it.
The second would be a solid setup minimal deflection. Kind of takes the bow out of a worn table. IMO
 
On your setup how are the ends held down?
Find which way your machine cuts more accurate. Your set up using the end of a endmill.
Or try taking the vice off. Use 123 blocks every 6-8 inches with hold down straps corresponding. Then side mill your max length loosen setup. Index the rest of your part and dial in of the surface you just milled. Your should be able to get as good as you can align it.
The second would be a solid setup minimal deflection. Kind of takes the bow out of a worn table. IMO

They are not held down on the end as I need to cut the full length. They are propped up by 123 blocks and adjustable parallels to eliminate flex/chatter. My machine jacks were too tall.

I do have a split vise that I could use to hold the piece with several parallel along the table. This is how I was going to attempt my fly cutting of the wide surfaces. All saw cuts and factory scale, working to get a surface that can be indicated from. Guess I need more 123 blocks.
 
The ends of the material would be vibrating with every revaluation of the cutter. You’d need the strap clamp the ends either way. And move as needed to work.
Fastening to table you can have the clamps come from the back of part and mill the front fully without the moving.
 
How straight does the gibbs, or way for a shaper have to be? In my mind, since you have two long sliding surfaces, and convex, or concave to the strip, will wear into a straight surface after a bit of use.


:dejected: Ok, let me have it!
 
How straight does the gibbs, or way for a shaper have to be? In my mind, since you have two long sliding surfaces, and convex, or concave to the strip, will wear into a straight surface after a bit of use.


:dejected: Ok, let me have it!

Interesting point. After watching Brian Bloc machine that unknown shaper back in to spec I noticed that Brian says Richard King had told him to put a .001 per foot taper on the machine ways to account for ram droop. I believe the sides of this gibb strip are irrelevant to the machines accuracy. Truly only the bottom of the gibb strip in contact with the way is the important face. Just trying to do my best with what I have. My surface plate is only a 24"x24" so I will have to "index" that step too.
 
On my shaper, my gibbs work best with .003 celarance for the oil to lubricate the gib/casting. With less, the ram bogs down. You have to experiment with your own machine, but less than .001 will give your trouble on most machines. I hope this helps!
 
Back
Top