new mill options

I kinda feel both aren t necessary and better off to see what you need to machine and go from there and figure out what is more valuable. Backlash once understood isn t that much of a deal. Screws don t lie but it does help one starting out.
I think a question to ask is how comfortable would you be later to add the dro. Buying upfront installed may be a good idea.
Both are great items to add to your mill. There is alot to buy or shall I say it never ends. That s my reasoning but that s me. Maybe the dro install might be your biggest question? The feeds can easily be added at anytime.
 
I would approach the decision a bit differently. Since you can install either of these yourself, look into the process and decide which (if any) you'd prefer to pay somebody else to install.

EDIT: oops, guess the preceding post made this point as well.
 
I installed some igaging ez -view dro's but rarely use them, I do use my x power feed all the time.
 
I agree to do the install and such. Just to be comfortable with it. Drilling and tapping into the casting and maybe a slight mod on a bracket due to casting or something. Might not even be a concern. You know what your comfortable with and I am sure you ll have a look before.
 
FWIW: I opted for the factory installed DRO with a PM25, and constructed the Z and X drives based on utube videos and helpful comments and posts on this forum. The PM25 was a "first mill drill" purchase after buying a small bench top lathe so lack of experience figured into the DRO purchase.

Constructing the motor drives were inexpensive projects to get comfortable operating the mill drill, and I quickly learned how useful the DRO is in practice.

Both inexpensive motor drives were fabricated without drilling, milling or permanent alteration of the "virginity" of the PM25, as I considered wanting to sell it and buying a larger unit in the future. The PM unit may have a higher resale value for CNC modifications by subsequent owners, over the comparable Grizzly units, and even higher resale value if it is a "Virgin" without holes bored or drilled into the base and column by an amateur machinist?

Buying the necessary components for the motor drives was also cheaper than the "cheapest" after market DROs which may or may not add to the resale value of the unit?



Again, FWIW.......
 
As one with no experience, I opted for the installed DRO and no power feed on my PM-27V. My desire was to learn how to cut metal with some precision and to do that I wanted equipment that was ready to go and had support. Six months into this effort, I find it was one of my better decisions.
 
MarkM said:
Screws don t lie but it does help one starting out.
Click to expand...

Yes, they can/do lie. Especially if the machine you are buying does not use top-shelf screws. Having a a system that measures absolute translation along a given axis is much superior to counting little marks on a dial. It also brings one into the 21 century. ;)
 
They still don t lie whatever srew it is. The thread on the screw and the mating nut have the same tpi. It s the operator not the srcrew. If one cant count to five and rotate a handle and gets tripped up I think there in for a world of hurt no matter the route you take. Backlash, well learn to use numbers and how to compensate for backlash not guess how many cranks. If The screw from the manufacturer is not built right it s out of this discussion.
You guys and the modern stuff think it s all the bees knees. Ya it s great and I can guarantea they ll be question like the dro says so but my part says different. What s up with that?
Have an imperial or metric scale along your x,and y axes. Oh theres the eighteen inches i need to move so ill mark my axis and then when I look and see that mark is near the eighteen i ll look down at my dial to fine tune. Easy peasy. They don t lie they are mechanically locked. Its all operator.
Id like to see some of you with these lower end dros do some test with some jo blocks (guage blocks) and indicators and see what kind of accuracy you have now with your Dro. Add a cut in there during your testing.
It a luxury and an aid. I don t need a dro I can manage without. Bolt circles and such can all be done mathematically.
Would I like one sure! I ll wait and get by until i can get a decent unit and the shop has caught up a bit.
So here will be another new machinist going right to a dro not learning the basic skills that would force him to learn some math and trig. Which will be all computer aided and you know it s not about this mill its about getting some routes that will help and stay with a person so they can grow not looking for a computer.
My whole argument is why not learn from the ground up. There will be times you ll have to revert doing something the old way because it is all you can work with. Not having the dro forces you to get that pad and pencil out and work thinks out
I Don t think were doing these newbies any good heading down this path from the get go. Will the rotary table have a dro? You know you should revert back to zero then hit your next angle.
Screws don t lie!
 
I too am a newbie, only having setup my PM-25 in January, so I'm about equal to you in experience. When purchasing my mill I was advised by friends to be sure that I included a DRO. I didn't know what that was. Even though it was expensive installed, I bought it that way because I knew nothing about a DRO and learning how to install something that I new nothing about, and making sure that it was done correctly, was one thing I didn't need to tackle. Learning how to use the DRO was interesting and fun and I was able to start that right away, without having to do the install too and worry if I did everything correctly. I still have a lot to learn about a DRO's capabilities and am glad that I didn't have to install it too.

One thing that I have learned is that the Z axis only works on positioning the head. There is another digital readout on the front (not backlit unfortunately, and operated only by battery, also unfortunately) that tells the position of the quill. I have yet to find a useful purpose for a Z axis readout on the DRO but use the quill readout daily. The quill readout can be adjusted .001" at a time, using the fine feed adjustment on the machine.

I still use the dials from time-to-time but, if I had to do it all over again, I wouldn't hesitate to order it with the DRO installed.
 
Nyala said:
One thing that I have learned is that the Z axis only works on positioning the head. There is another digital readout on the front (not backlit unfortunately, and operated only by battery, also unfortunately) that tells the position of the quill. I have yet to find a useful purpose for a Z axis readout on the DRO but use the quill readout daily. The quill readout can be adjusted .001" at a time, using the fine feed adjustment on the machine.
Click to expand...

With a knee mill, you generally use the Z axis to set depth of cut, and only use the quill when doing boring or drilling (for which it has an auto-feed). The reason is to increase the rigidity of the setup: the more stickout the quill has, the less rigidity there is for end- and side-milling.

The difference in rigidity isn't going to be as great with a PM-25, but it's still probably a good idea to get in the habit if setting depth of cut with the Z axis DRO.

EDIT: I should amend this to point out that most advice on cutting is "rough it to within 0.002, then do a finish cut". The finish cut can(/should?) be done with the quill, as it is a light cut.

As for whether to start out with a DRO, I think there's a fine line between learning the fundamentals and outright hazing (aka "conditions sucked when I learned to do this, so they should suck when YOU learn it too!"). I don't believe that a DRO interferes with learning the fundamentals. In fact, if anything it improves them as the newcomer can focus on learning proper speed, feed, and depth of cut without worrying about keeping track of how many handwheel cranks as well.
 
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