We do a lot of work for Martin owners since we are a certified warranty center. Martin provides dealers with the ability to purchase the saddles that they use in production.
Normally we only provide high quality bone saddles that are individually crafted and intonated for the specific instrument. But for Martins it's way easier for us at times when a new saddle is needed to use a Martin OEM bone, compensated saddle. It's cheaper for our clients too since we charge more to customers make one from last weeks pot roast.....
Long story short Martin bridges are CNC produced with usually very accurate saddle slots that the OEM saddles nicely and snugly fit into the slot with zero gaps. I usually have to swipe the sides of the new OEM saddle a few times on 320 paper on a surface plate and I always when replacing a saddle draw a pencil line on the bottom and then mill that saddle bottom on a surface plate with paper on it to be sure it's absolutely flat for pick-up response reasons.
Another topic but we often mill the bottom of saddle slots because they are not level and the complaint is uneven pup response. This fits that usually and is a unique things we do with the saddle mill. We need to be able to mill the slot bottom only without touching the slot sides, that's not possible with a sloppy .005" runout lam trimmer.
So these OEM saddles can't be made thicker..... well they could but it would be hack work.... so the precision of the slot is important here to use OEM parts where desirable.
Throw in the fact that in the early 70's many Martins had their saddles improperly located (bad jig) and I speak of 18's, 28's and 35's. To this day they are still showing up and often it's the case that the cowboy chord players never noticed that their D-18 had poor intonation which is hard to notice if you live your life playing a G, C and D...... But then they die, the guitar changes hands, the new steward likes to play the greatest song ever written, Smoke on the Water and then they notice that the intonation is off.
So it comes to us and Martin will cover this under warranty had this guy been the original Smoke on the Water player but since he is a second owner he has to pay us.
We use the saddle mill to true up the existing saddle slot, find a matching blank wood/material and make a plug. We plug the bridge saddle slot shooting for invisible even matching grain when we can. Then we mill a new slot where it was supposed to be all along. It's a pretty cool fix the bridge never has to leave the instrument either since our mill is vacuum clamped on the guitar top and immobilized completely. We've done this on near priceless pre-war Martins too and it's safe, predictable and never has failed to do a great job.
Now with very little runout we can cut the slot to be a near perfect match for Martin's OEM saddles.
We can also do other cool tricks such as tilted saddle slots or for through saddles where a UST (under saddle transducer) never would have worked we can mill a special pocket for the UST under the through saddle preserving the vintage and traditional look and bringing modern electronics to an old dog with a minimally invasive and reversible mod.
With all of this said we also use the mill to route pick-up cavities and such. Runout of .005 would have been a non-starter for us and much of what I described above would not be possible with professional, very high quality results if the dang tool was sloppy as can be.
Going back to bindings. I don't know about others here but for me I was obsessed with uniform thickness binding everywhere on my guitars including on the back by the neck heel a place where traditionally bindings can get very thin. That 10% variance in a .050 thick binding would be a show stopper for me. I'll go further that on a multi colored purf 10% of slop might remove an entire color in certain places.
So if anyone is trying to make the case that .005" of runout on a brand new tool and for how and what we use lam trimmers for with Lutherie in my experience this is an area where the utmost precision is beneficial and always worth shooting for. This is also very much a question of personal standards, YMMV and I don't care
(actually I do or I would not be here....) My ex boss Jack Welch was famous for saying be number one or number two in all that you do or go do something else..... He also made 80,000 share holders millionaires. Neutron Jack RIP.