DRO suggestions for mill

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john_j
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DRO suggestions for mill

Post by john_j »

I'm looking to buy a DRO for my JET JVM-836 mill. For those not familiar with that mill, it is an 8 x 36" floor standing knee mill.

I have a Shooting Star DRO on my lathe that I am happy with and I am considering getting one of those for my mill, but I wanted to find out if there was anything better in the same price range. I am looking to spend a maximum of $1300 (but under $1000 would make me very happy) and I want a 3-axis system.

I ran across this one on the web today: http://www.dropros.com/Milling%20Machines.htm

It is an Easson ES-10. I had never heard of that brand, but that model is a 3 axis, 0.0002" resolution, for $800. According to the specs, it is more accurate than the Shooting Star.

This is a hobby type application, not a production shop and I probably won't need to hit specs on parts tighter than +/- 0.001".

Please comment on the Easson ES-10 if you can and give any other advice you have regarding what you think I should do.

Thanks
recoilless
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Post by recoilless »

John: try the search function on the HSM page. I asked about that particular DRO a while back. IIRC, they were popular in Australia.
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MikeG
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Post by MikeG »

John

Hi, I have the same mill and I use an Accurite that I bought with the mill, it's a very accurate DRO, Had one problem with it after about two years (transformer in the power supply) called accurite and sent it in for repair, they said that this should not of happened, they fixed it at no charge. The JVM-836 is a great mill.

MikeG
In the shop; a Jet 8x36 vert mill, Jet 13x40 lathe. Harig 612 SG. Burke #4 HM. Van Norman #76 piston griinder
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ALCOSTEAM
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Post by ALCOSTEAM »

I have an accurite 3 axis on my bridgeport. Enco has had them on sale for just over a grand and once in a while they will also do an extra 10% off sale. I need to pick another one up for the cincinnati.

tim
big art
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Post by big art »

I have a bridgeport mill I bought without dro. After searching for the most needed features at the lowest price I chose the Grizzly dro, it's an import. I think I paid $800 -$900 for a three axis unit, I haven't mounted the third axis yet. Some of the features are built in calculater that can transfer dimensions directly to the dro, it can do linear hole positioning, positioning holes on bolt circles, in these features when you finish the first hole hit arrow for next location and the dro will count down to "0" as you move the table to the next hole and so on. It has an R function that allows you to position your tool to machine a radius in XY XZ & YZ planes this feature is for simple arcs only. Check them out, they are made for several sizes of mills or lathes in 2 or 3 axis operation.
MichaelC
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Post by MichaelC »

I have used a Shooting Star for 3 years and Newall for almost 3 years. No comparison. Shooting Stars are accurate to .002" full range according to their own documentation. Newall is accurate full range to .0002" with no cumulative error like Shooting Star is prone to. The Newall costs more, but is impervious to chips and oil and is very easy to install compared to Shooting Star. I wish I had never wasted my time on Shooting Star, they work but no where near as accurate as Newall. No fault 3 year warranty on Newall. If you shop around you can get 2 axis for about $1000. Made in England. In defense of SS , they are fine people and stand behind their product, but gear rack and reader are not in same league as glass scales or the system that Newall uses.

michael
Rich_Carlstedt
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Post by Rich_Carlstedt »

Michael
You are way to harsh about readouts
No Doubt, the best is Newall, because they use a closed tube and measure inductance, and the least affected by contamination.
They are also the most expensive !
The man asked for a 3 axis DRO under 1300, He will never find that in a Newall. If you know, tell him where to find it. Even on eBay, a 2 axis Newall goes for 1150 plus .
I have a shooting Star, and I am within .0005 when compared to a Pratt and Whitney 12 inch standard, and " Yes" , it not as accurate as a Newall, but thats apples and oranges my friend. There is a 2 to 1 price difference !

As a second note, Glass scales can be very accurate, But, and that is a big BUT (!) if your shop has changes in temperature, you must be concerned with thermal expansion. Simply put, Newall and Shooting Star expand at the same rate as your table (.0000063 in per deg F) and glass scales do not ! That is a growth or shrink of .002268 inches with just a 10 degree change on a 36 inch table. that alone blows away all the desired accuracy spects
Is this a concern ?...not unless you make rockets
Guys in the home shop hobby make too big a deal out of sometimes meaningless data
Ease of operation and adaptability should be paramount !

The Easson tech specs look good
It is a Chinese company and you can read their website at

http://eassonco.en.ec21.com/product_det ... al_Readout

or go to :
http://www.easson-co.com/displayproduct ... kin=2&id=7

for the technical specs they filed with the trade organization.
Here they say that the accuracy over 18 inches is .0004"
accuracy =(over 500 mm = 10um)

Newall is British
Sony and Mitotoya are Japanese
Accurite and Analam are American
Shooting Star is Canadian
Esson Ltd is Chinese

Rich
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LivingLegend
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Post by LivingLegend »

Try this link for Can-Do Machinery. They specialize in DRO's and carry the major players... Those mentioned above as well as a few others. Good prices and staff is knowledgable.

http://www.candomachinery.com/

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MichaelC
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Post by MichaelC »

Rich C.

Not trying to get into a pissing contest on DRO's. If you can go full length on your mill repeatedly back and forth and come back to start and be within .0005" you are doing very well indeed. Most folks would be thrilled if their Shooting Star would do that.

Dealer cost on 2 axis Newall is about $900 for a small dealer ordering one at a time. I walked into my local guy slapped down cash and he ordered me one for $950. At that time Ganesh was selling them for that price also. I figure with inflation since I bought mine in spring 05 that one could be had for about a grand and few hundred more for 3 axis.

michael
Rich_Carlstedt
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Post by Rich_Carlstedt »

Well Michael, I just went into the shop
Set a stop, set up a dial indicator
Ran up to the stop and made sure after 3 times that
it registered "0" each time, then I zeroed out the Shooting Sstar
and went full length and came back to the stop.
Did it 20 times, then my arms gave out ( no power feed
I got a "0" reading on the Shooting Star 14 times, and a plus .0005 the other six.
Then i did it a number of time with only 8 inches of movement and it Never deviated from "0".
Let me say, that for home shop use, this is fine, and perfectly acceptable.
Before you get your "knickers in a twist"( british slang) realize that so much else goes into accuracy and repeatablity.
Most mills will 'Rock" when moved from one end to the other.
A DRO will NOT reflect this change
Thats because the Knee acts as a pivot point and the shift of table/vise weight causes considerable load shifts. This means that if you want to drill 2 holes exactly 24 inches apart, the rock will probably cause them to be at 24.003 or even more, depending on wear, gib conditions, weight and even drill forces, and which axis's are clamped

If someone has a problem with 'repeatablilty', they have to look at the mill as a whole , and the DRO installation too. I feel the brand of DRO is the least of their worries......if they want true accuracy.
I am sure Harold could even go further in describing all the facets of machine function to get good work, having done so in the aircraft industry

Rich
Rich_Carlstedt
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Post by Rich_Carlstedt »

I suggest if you are not getting good repeatability, you give Shooting Star a call or send them a email and ask why .

Rich
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Harold_V
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Post by Harold_V »

Rich_Carlstedt wrote:I am sure Harold could even go further in describing all the facets of machine function to get good work, having done so in the aircraft industry

Rich
I'm flattered by your comment, Rich.

When it gets down to tight tolerance work, you learn to do things differently, of that there is no doubt. One of the things you quickly learn is to not touch the machine, aside from the handles. Even setting locks tends to disturb a setting.

Truth be told, I have never used a DRO in my life. I did mind numbing work using nothing more than the screws on my machines and applying my experience, along with the use of indicators when appropriate. I like working that way.

Frankly, for me, I see no need for a DRO-----one would tend to make me lazy and possibly cost me ability in the way using a calculator instead of a pencil and paper does with math. That isn't likely important to others, but it is to me.

Each must choose the path that works best for them. DRO's are a very nice accessory-----especially for folks that don't have a great deal of experience and are prone to making mistakes using dials. It takes a great deal of practice before that comes easily. DAMHIKT. :-)

Harold
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