# 3 axis DRO installation on a 9x42" Bridgeport Mill



## Holescreek

A 6" vise is overkill for a RF45 style mill. A 4" is more appropiate for that size mill & IMO 5" max. I have a 5" GMT vise on my PM45 & it's slightly too big. Not enough Y axis travel to make use of the 5" full capacity. Better to save your money rather than getting something too big & most importantly the weight. I take my vise of the table quite often, a 6" is still light enough for me to be carried by hand but I'm glad I have a 5". I also have a 4" vise as well. I prefer the 5" though.

But those GMT 6" Premium vises are pretty nice. I'd love to have one but don't need one on my current mill. But if you plan on upgrading to a full size knee mill in the future than the 6" will be perfect.


Here's what the 5" looks like on my mill.




I couldn't even complete this cut without my bellows & DRO scale getting in the way. Not enough Y travel & the 5" vise is not even maxed out.




Here's what a 6" vise looks like on another PM45 (gt40's)
View attachment 253544


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## RandyM

What a well done job. Thank you for taking the time to post your project.


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## Rick_B

Thanks for the post - I may be in the middle of the same thing in the future. If you don't mind saying - what DRO are you using?

Thanks
Rick


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## Holescreek

This is the 3rd DRO I've bought from the same seller.  I can't find anyone that beats his prices for the same unit.

http://www.ebay.com/itm/182295304583?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT


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## Rick_B

Sorry for the question - I now realize this is the unit tyou already pointed out to me

Rick


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## bruedney

Thanks for the pictures
I am getting a BP in the next month or so and, after a VFD, the DRO is next

Cheers
Bruce


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## Holescreek

A 6" vise is overkill for a RF45 style mill. A 4" is more appropiate for that size mill & IMO 5" max. I have a 5" GMT vise on my PM45 & it's slightly too big. Not enough Y axis travel to make use of the 5" full capacity. Better to save your money rather than getting something too big & most importantly the weight. I take my vise of the table quite often, a 6" is still light enough for me to be carried by hand but I'm glad I have a 5". I also have a 4" vise as well. I prefer the 5" though.

But those GMT 6" Premium vises are pretty nice. I'd love to have one but don't need one on my current mill. But if you plan on upgrading to a full size knee mill in the future than the 6" will be perfect.


Here's what the 5" looks like on my mill.




I couldn't even complete this cut without my bellows & DRO scale getting in the way. Not enough Y travel & the 5" vise is not even maxed out.




Here's what a 6" vise looks like on another PM45 (gt40's)
View attachment 253544


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## bruedney

Hi Holescreek

Would you mind telling us the sizes of the scales you ordered?

Cheers
Bruce


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## Holescreek

bruedney said:


> Hi Holescreek
> 
> Would you mind telling us the sizes of the scales you ordered?
> 
> Cheers
> Bruce



X- 800, Z- 450 and Y- 350mm.  The 800 has about an extra foot of scale you'll never use but it sure makes it simple mounting on the 42" table and not having to worry about the reader head placement. (and the price is the same anyway.)


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## bruedney

Awesome thanks


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## FOMOGO

Well thought out installation Bruce. Price seems pretty hard to beat. Do you know off hand what features may be lacking vs say the dro-pro version which runs around $700? Thanks, Mike


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## Holescreek

I'll go out on a limb and say that Bruce probably won't want to take the time to research the features of each unit to answer your question.  I know I wouldn't. I bet that the manual that comes with the $700 unit is a hell of a lot easier to understand than the $300 unit.


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## FOMOGO

Know what you mean. Just figured someone who has done several of these has probably researched it pretty well. I did take a quick look on e-pay and here is the higher end DRO-PRO version. The descriptions can take a little evaluation if your not familiar with all the terminology. Thinking someone who is more familiar with them could clear up some things for those of with less experience. Mike




- *5 um (0.0002")* resolution scales (display supports 0.1-10 um scales as well)

- Can be switched between Mill, Lathe, Grinder and EDM

- Supports both English and Metric units (in/mm display)

- Absolute and Incremental measuring mode

- Center line (1/2) function

- Sub datum (200 points)

- Linear drilling function Mill Mode

- Bolt circle (PCD) machining in Mill Mode

- Incline and oblique plane machining Mill Mode

- Simple and Smooth Radius machining Mill Mode

- Asymptotic machining of inner cavity (chambering) Mill Mode

- Radius/Diameter function in Lathe mode

- Tool compensation with 200 tools library in Lathe mode

- Taper function in Lathe mode

- Axis summing in Lathe mode

- Filter in Grinder mode

- Linear and non-linear error compensation

- Auto Zero/reference function

- Calculator with trigonometric functions

- Sleep Mode

- Power Off memory

- 100-240V, 50/60Hz universal AC power

- Mounting Arm and hardware included

- ISO 9001 certified quality control, CE certified


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## Kroll

This is a fantastic post,just in time.To me I can't imagine a BP without a DRO or any mill without it.Like others and as posted by Fomogo,just don't understand all the technicals that goes with DRO,so this post is outstanding.Showing how to install by Holescreek helps to give ideals which I have no imagination so this is a big help.Thanks for posting---kroll


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## bruedney

Holescreek said:


> X- 800, Z- 450 and Y- 350mm.  The 800 has about an extra foot of scale you'll never use but it sure makes it simple mounting on the 42" table and not having to worry about the reader head placement. (and the price is the same anyway.)


I now have the BP in my workshop and am looking at getting the DRO. Can you please confirm that the lengths are the travel of the slides not the overall lengths? Thanks in advance
Bruce


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## Holescreek

Yep, travel length.  Check your own machine before you order. Run it all the way to a stop and make a line with a marker that goes across the moving and non moving surfaces. Then crank the axis fully the other direction and measure the distance between the two lines.   I have occasionally seen BPM's with an extra length knee which would make the Y axis longer than usual.


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## bruedney

Thanks 

Will do when I find the machine under all the crud

I have found that it is not painted black

Cheers

Bruce


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## bruedney

Hi
Any chance you can update the thread to fix or replace the Photobucket links?

I am almost at the point of fitting scales and would like to remind myself how you did it.

Cheers
Bruce


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## Holescreek

bruedney said:


> Hi
> Any chance you can update the thread to fix or replace the Photobucket links?
> 
> I am almost at the point of fitting scales and would like to remind myself how you did it.
> 
> Cheers
> Bruce




I can't fix my threads without edit privileges.


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## bruedney

Awesome - Thanks heaps


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## Kroll

Any updates on your installations,what kind of DRO did you go with?If possible post some pics of your process,love to follow along----kroll


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## 4ssss

What you may want to do is put a small stand off below the scale for the X axis so you can't run the table into the column when cranking it in. The pic I posted shows my scale with just a 5/16 cap screw used as my stand off. If the table is cranked in too much the cap screw will hit the column instead of the scale.


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## Insight

My lathe didn't come with a DRO so I bought a three-axis unit that I haven't installed yet.  The mill came with a two-axis DRO on it.  I've purchased a lathe tail-stock battery operated DRO and am planning to put the three-axis on the mill and transplant the two axis to the lathe.  I haven't checked yet to see if the slides are interchangeable.  Sounds like from the thread that the z-axis usually goes on the table.  I guess one could also put a tailstock type DRO on the quill.


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