Quill vs. Z axis (or both) DRO on a PM30

[Spotshooter]

Has anyone installed a DRO that measures both...

The PM30 I have as a quill DRO, but I read in the manual if you buy it with a 3 axis DRO it measures the head height on the z axis, but not the quill... but if you install one after you can measure both.

I‘ll ask PM for an instruction manual for installing a 3 axis DRO like that but I was wondering if anyone has done it already.

Thanks,
Spot

 

[RJSakowski]

I installed a DRO on a Grizzly G0755 which is similar to the PM30. I installed the z axis scale on the quill. I have an archive of the SolidWorks models for the parts. I used the Grizzly glass scales which are essentially the same as those sold by DRO Pros.

 

[RJSakowski]

Here is a side view of the scale mounting. The pickup head is adjustable for alignment purposes.

 

[mksj]

Most individuals on bench top mills use a separate battery operated quill DRO, just much simpler and less bulky approach. You would need a 4 axis DRO if you wanted to do a summation of the two and there may be inaccuracies once you lock down the head. When I had a benchtop I never found the need for a Z axis column head scale, you typically move the head, lock it down and then use the quill for depth. At least that is what I did, because there was a little nod in the head when the Z was not clamped. On my knee I have 4 axis DRO with magnetic scales, it does summation of the knee and quill travel. I Like having all the readouts in one place and the higher quill resolution, but I rarely move both the knee and quill for milling a part. You are also looking at a significant higher expense going to 4 axis. Glass scales are a bit trickier to mount and also are bulky for quill mounts.

One option if you want to go to magnetic scales would be the ES-12B 3 axis with magnetic scales sold out of the UK for around $800 delivered, you could use the 3rd axis either on the head or the quill. They are nice DRO's and the scales are compact.

 

[Spotshooter]

Mine has a digital battery operated DRO on the Quill already... so I’m not 100% sure that’s enough.

A few guys said I shouldn’t use the quill for the most part, just to do final changes to what ever I have on the Z axis... however I’m a gunsmith so I’m only drilling for the most part so I’m thinking one on the column is more than fine....

I thought Easson 12b’s were optical ?

 

[DavidR8]

I don't have a PM30 mill but I put a DRO on my round column mill.
I only have it for the quill. My rationale is that I adjust the height on the column to get in the range I need not for precise depth control. I get that a square column doesn't have the alignment issues of a round column but I could still only see using the quill to make depth adjustments of DRO precision.

 

[mksj]

Quill is just as accurate as the column for depth, I routinely mill to 0.0005" tolerance height w/o problems. The issue is as the quill extends you loose rigidity and get more flex, so for big or deep cuts you use it for more fine adjustment. Also depends on the mill, and if you are using an R8 collet or say a chuck or long end mill.

Easson 12B is available through Machine DRO UK and the ship air freight and runs around $800 with shipping. Some people seem to get hit with $70 customs fee, it varies but I saw elsewhere that anything over $750 gets tagged. You can specify encoder lengths and resolution, as a number of HM individuals have purchased these for lathes with a 1 micron reader head for the cross slide. The scales are very easy to cut and very forgiving of alignment. DRO Pros have more refined kits, but also quite a bit more expensive. There is a US vendor SRA that sells the Easson DRO's and magnetic scales, but they are more expensive and do not have kits so you need to order everything separate and they do not supply brackets.

Easson ES-12B LCD digital readout package including 3 linear magnetic encoders

3 Axis Easson ES-12B LCD graphic digital readout package with three magnetic encoders. The encoders offer a very compact profile size and can be cut to length to custom fit the machine being installed. The package is suitable for mills up to Bridgeport 42" sized machines or 30" between centre...

www.machine-dro.co.uk

There are US vendor's that sell the Ditron D80 with magnetic scales, but I consider the Easson a bit better DRO.

Ditron D80 3 Axis Mill DRO Kit w/ Magnetic Scales

Value Added Distributor

www.machinetoolproducts.com

 

[Spotshooter]

Thanks MKSJ,

Yeah I saw DRO pro guys were pricey, I was thinking of getting glass vs. magnetic, but I need to do some reading on it before I pick which one.
PM has a nice 3 Axis DRO but they say it won’t be in stock until next year, so I started looking at the Easson versions because I have one of them on my lathe.

 

[WyoGreen]

I have the PM30mv with the PM installed DRO. As has been mentioned, the Z axis dro on the head is really not needed, as I lower the head close to where I want it and then lock it down. I then use the quill mounted DRO for the finial adjustments. The quill DRO is actually kinda nice, as its right there in front of your face while doing the final adjustments. From my experiences, I'd say a person would do just fine with a 2 axis dro for the X and Y axis, and the quill dro. I did pick up a power supply on ebay to eliminate the battery in the quill dro.

Steve

 

[Spotshooter]

Thanks Steve, I was thinking that more and more... I use the quill DRO when going vertical... I really need the X & Y though...