[4]

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

[3]
[10] Like what you see?
Click here to donate to this forum and upgrade your account!

madmodifier

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Jan 7, 2014
Messages
79
Likes
51
#1
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].jpg IMG_20181020_184231820[1].jpg
 

Bob Korves

H-M Supporter - Sustaining Member
H-M Platinum Supporter ($50)
Joined
Jul 2, 2014
Messages
5,649
Likes
5,958
#2
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.
 

Dabbler

Administrator Trainee
Staff member
H-M Supporter - Gold Member ($25)
Joined
Oct 11, 2016
Messages
568
Likes
416
#3
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!
 

madmodifier

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Jan 7, 2014
Messages
79
Likes
51
#4
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.
 

Cadillac

Active Member
Registered
Joined
Mar 12, 2018
Messages
443
Likes
478
#5
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
 

madmodifier

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Jan 7, 2014
Messages
79
Likes
51
#6
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.
 

Cadillac

Active Member
Registered
Joined
Mar 12, 2018
Messages
443
Likes
478
#7
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.
 

Superburban

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Jan 2, 2016
Messages
550
Likes
410
#8
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!
 

madmodifier

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Jan 7, 2014
Messages
79
Likes
51
#9
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.
 

Dabbler

Administrator Trainee
Staff member
H-M Supporter - Gold Member ($25)
Joined
Oct 11, 2016
Messages
568
Likes
416
#10
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!
 

madmodifier

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Jan 7, 2014
Messages
79
Likes
51
#11
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!
Thanks. I was not saying that I was going for .001 clearance, I was saying that the suggested way taper would be .001 per foot. Clearance between the Gibb strip and way was on my to ask list however. I will shoot for .003!
 

Bob Korves

H-M Supporter - Sustaining Member
H-M Platinum Supporter ($50)
Joined
Jul 2, 2014
Messages
5,649
Likes
5,958
#12
Thanks. I was not saying that I was going for .001 clearance, I was saying that the suggested way taper would be .001 per foot. Clearance between the Gibb strip and way was on my to ask list however. I will shoot for .003!
When the ram is all the way extended, clearance turns into droop, at least part of it does. Oil helps to fill the gaps, but being a liquid it squirms out. Other machines do the same. Milling machines and surface grinders both have tables that travel far beyond the supporting ways and gibs. That becomes droop at the ends of the travel. There are ways of dealing with it or compensating for it.
 

P. Waller

H-M Supporter - Sustaining Member
H-M Platinum Supporter ($50)
Joined
Mar 10, 2018
Messages
570
Likes
373
#13
Move the part, it will not be PERFECT and you will not like it but is the only choice.
Or buy a machine large enough for the work.

A 60" travel machine milling a 110" long part, not ideal but the only option. $5000.00 worth of Kurt vices helps but it still will not be PERFECT by hobby standards.
 

Cadillac

Active Member
Registered
Joined
Mar 12, 2018
Messages
443
Likes
478
#14
Shows ya that no matter what size machine you have some jobs demand more.
 
[6]
[5] [7]
Top