Magnetic dro scales on lathe

R

Romano

Plastic

Joined

May 9, 2018

• May 28, 2018

• #1

I have for a long time wanted a dro on my Maximat V10P which is a very small lathe with very little room, and the extra challenge of the milling attachment at the rear. A couple of people appear to have done this successfully, using magnetic scales and quite small readers (like rls lm10).
Now, I was doing some tool post grinding on a cast iron job the other day, and the fine iron dust got me thinking - is this an issue for magnetic scales? Has anyone had problems with fine ferrous dwarf in conjunction with magnetic scales? And what about is I use a magnetic dial indicator base on the crossslide? Any issues?
As usual, grateful for any advice.
Roman

 

H

HuFlungDung

Diamond

Joined

Jan 19, 2005

Location

Canada

• May 28, 2018

• #2

I've been running Sony Magnescales on lathes and mills for years without ever any problem with dust. A lot of this was 'dry' machining, so there is plenty of dust around and cast iron dust in large quantities as well. The aluminum scale housing on my scales is nearly 1" x 1" so the magnetic rod is about 1/2" away from anything. The lip seal along the bottom does a moderately good job of sealing, although there is bound to be some gap near the reader head.

I'm supposing that the magnetic imprint on the rod is so miniscule, that the field strength falls off rapidly with distance and so it doesn't behave like a magnet in the normal sense. I also clean up with a strong stick magnet in the vicinity of the Magnescales and I don't worry about damaging the scale either. Just doesn't seem to be an issue.

 

rklopp

Diamond

Joined

Feb 27, 2001

Location

Redwood City, CA USA

• May 28, 2018

• #3

I have a coarse resolution Magnescale for the carriage travel on my Colchester that consists of a magnetic strip stuck to a piece of aluminum angle. The strip is out in the wide open air, but does face downward. I have never had an issue with it. The read head has little wipers that are like way wipers on either side of the actual reader. I cut the scale down from about 6’ to fit my lathe’s shorter bed. I think this type of scale was mostly marketed for big lathes and HBMs.


Sent from my iPhone using Tapatalk

 

R

Romano

Plastic

Joined

May 9, 2018

• May 28, 2018

• #4

Thanks - that’s 2 - 0 saying “no probs” so I’m very encouraged.
Has anyone’s experience been different?

Roman

 

TDegenhart

Diamond

Joined

Mar 26, 2011

Location

Geneva Illinois USA

• May 28, 2018

• #5

My HLV-H knockoff uses a Newall microsyn system that I have no problems with. It is small and easily assembled. The read head is sealed, the actuating rod is out in the open. Its magnetic in the sense of being variable reluctance.

Tom

 

Rigor

Banned

Joined

Jun 16, 2016

Location

Canada

• May 28, 2018

• #6

Like the others I have nothing but praise for the mag scales. I changed out a glass scale unit on my machine with a M-DRO magnetic unit and never had a problem. Installation is a breeze and the nice part and what sold me on them, is you can cut the magnetic strip to fit your machine, without affecting the system.
On this lathe, the cross slide magnetic strip is covered by a piece of aluminum angle and is open at both ends. Here is a pic after finishing a job. As you can see with all kinds of swarf, it has no problem being stable and repeatable.

 

R

Romano

Plastic

Joined

May 9, 2018

• May 29, 2018

• #7

Rigor
Thanks. That’s a neat installation there. What read head are you using? A couple of posts suggest not to put the scale on the headstock side because of the increased risk of inadvertent damage. Have you had any reservations?
Roman

 

rklopp

Diamond

Joined

Feb 27, 2001

Location

Redwood City, CA USA

• May 29, 2018

• #8

Beware that Sony Magnescales with enclosures are hard to cut, because the magnetic strip is welded at each end and the strip is under tension. The strip is free-floating in between the ends. This is not like the coarse-resolution Magnescale I mentioned above in post #3, which was very easy to cut.

 

L

Lakeside53

Stainless

Joined

Sep 28, 2007

Location

Woodinville, WA

• May 29, 2018

• #9

I put the DROPros mag scale system on my 17x60 lathe. Perfect.. no issues.

 

Rigor

Banned

Joined

Jun 16, 2016

Location

Canada

• May 29, 2018

• #10

Romano said:

Rigor
Thanks. That’s a neat installation there. What read head are you using? A couple of posts suggest not to put the scale on the headstock side because of the increased risk of inadvertent damage. Have you had any reservations?
Roman

Click to expand...

The encoder( read head ) on that machine is an M-DRO EH-05. It has 5 micron resolution and is low profile sealed to IP67. I'm quite happy with it, two years in.

Now as to best place where to mount it, well thats really up to you. But, the reason I have mine on the headstock side is because on the opposite side is the gib. The gib's job is to pull the crosslide in to the dovetail that the axis you are measuring registers to.
As for risk of damage, well it is up to the operator to be aware of the sensitive( not really ) piece of hardware that is just behind the cutter. In other words, you compensate and get used to it.
Good day......