DRO Complete with photos

Discussion on all milling machines vertical & horizontal, including but not limited to Bridgeports, Hardinge, South Bend, Clausing, Van Norman, including imports.

Moderators: Harold_V, GlennW

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thedieter
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Post by thedieter » Thu Dec 31, 2009 7:39 pm

Bill:

I posted only part of the mods to the fine down-feed.

One fairly easy improvment that I made was to preload the ball bearings on the hand wheel shaft. I did it by making a sleeve that fits inside the dial that is slightly longer han the dial spool, removing the snap ring that holds the ball bearings and use the spring lock washer to preload the bearings by tightening the hand wheel nut as required.

This fix eliminates some of the backlash that is caused by the shaft moving back and forth. I can give more info if anyone wants it such as sleeve OD, length, etc.

There is one other mod that requires removing the return spring which is a tough one as that spring is a bugger to get back on.

Best regards, Jack
Last edited by thedieter on Sun Jan 10, 2010 3:06 pm, edited 1 time in total.

CarlD
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Post by CarlD » Thu Dec 31, 2009 8:08 pm

The Z readout is in the knee because it's the best place for it. Have you tried to hand feed the quill and get a smooth feed and exactly .001" at a time? If you have you will know why if you want to take .001" at a time cut the knee is the only way hense, the DRO reader on the knee.

Most machinists learn it's best to move the quill to the work surface, lock it and use the knee to make the DOC with.

Having a digital caliper mounted on the quill may be handy but for the most part is is useless for exact work.
It's only ink and paper.

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tailshaft56
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Post by tailshaft56 » Thu Dec 31, 2009 8:33 pm

seal killer wrote:Jack and Frank and tailshaft56 and coal miner--

coal miner, ha! I figured you would be all over this one!

tailshaft56, forgive me for asking if you have already posted it, but what mill do you have? Did you choose the Grizzly DRO?

Jack, you certainly did an excellent job and I am eager to hear about your results!

Happy New Year to all!

--Bill
Bill, I have a Precision Mill/Drill from Wholesale Tool. Ot's nearly identical to a Rung-Fu or the Grizzly M/D. Yes the DRO came from Grizzly I highly recomend the DRO Pros website. They have some great video's on selecting and measuring for your dro. They also have some viseos in the functions of the Easson DRO. Grizzly DROs are manufactured by Easson.
Dennis


Thermal Arc 185-TS
Millermatic Challenger 172
Victor O/A
Atlas Craftsman 12 by 24 Lathe
Esab PCM-875
Wholesale Tool Mill-Drill

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coal miner
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Post by coal miner » Thu Dec 31, 2009 8:55 pm

CarlD , having never worked around a milling machine , I just did what came natural to me on feed to the work . Worked around 2 generations of lathe operators , but our job had no mills and an old line fed shaper that I saw used maybe twice in the 15yrs that I was associated w/ our welding shop .We had two lathes that were much older than I was and so where the two operators . I learned a lot from those old guys , they knew what parts you would need the most to keep the mine running . Good men ! The feed on the knee of mill we have , G-3616, is 1 turn = .200" . Looked kind of fast to hit a .001 . I can see that it would be a better op to use the knee because of not having to extend the quill and also with bringing the work closer to the cutter . Will pursue this .
This education of the right way to do certain things is a Godsend for a guy like me . That's one of the reasons I like this site .
The more I learn , The more I don't know !

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seal killer
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Post by seal killer » Thu Dec 31, 2009 10:15 pm

Carl--
The Z readout is in the knee because it's the best place for it.
I did not think the knee was the best place for the DRO. I could be wrong. My knee crank moves 0.200" per revolution. This is not good. It is difficult to get a "fine tune" at that rate. The fine down feed moves 0.100" per revolution, twice as good as the knee.

This is how I mill: I bring the knee up as high as possible and lock it. Then I move the quill to perform milling. In most of my work, this movement amounts to no more than two inches, usually much less.

Give me your opinion of what I am doing. No ego here.

Thanks and have a Happy New Year!

--Bill
You are what you write.

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thedieter
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Post by thedieter » Thu Dec 31, 2009 11:15 pm

Coal miner and Bill:

Recheck your Z axis...mine is .250 per turn and I would think yours is the same. The DRO gives a much better "feel" on the knobs and cranks and it is possible to nudge the readings by .0002 in. increments.

Since it is difficult to add digital readout to the spindle of my mill I think that I will go with CarlD's method and I can consider the job done. :D

Best regards, Jack

CarlD
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Post by CarlD » Thu Dec 31, 2009 11:26 pm

The Grizzly G3617 mill looks to be about the same size as a BridgePort. I have a MillPort which is a knock off copy of the BridgePort. The Knee dial is .100" per turn I can get .0005" if I am careful but with a DRO on the knee you should be able to get it exactly. I wish I had gotten a DRO with the knee readout but as I said, I get good accuracy with mine as it is.

when you use the quill to hand feed with an endmill to plunge you can feel the pulsation in your hand as it cuts. It's also hard to get .001" at a time with the quill, even with the hand wheel. If you lock the quill and use the knee crank you won't feel any pulsation and it won't cause the endmill to grab.

The best way if your drilling in brass, copper or cast iron is to lock the quill and use the knee to feed the work into the drill or endmill. The only thing that may happen is the drill or endmill gets pulled out or the work gets pulled out of the vise. I have had a drill sucked into brass trying to drill in brass and copper. If your cutting a counterbore for a socket head it's best to lock the quill and feed with the knee, it's more accurate but sometimes I set the quill stop and plunge cut by hand to the stop with some drag on the quill.

Of course you could snug the quill lock and use the quill hand wheel to manually feed the quill down but things can still grab and mess up your work. Without the quill locked tight it can get sucked into the work.

There are so many things that can happen when feeding with the quill. That's not to say I use the knee all the time. I use the quill when drilling or power tapping. If I am flycutting or using an endmill I always feed with the knee. I use the knee when I am cutting a keyway. One good thing about doing that is you can have the quill extended about one or two inches and use the knee to make the DOC feed. Then retract the quill, move the X travel and measure the depth of the keyway, return the tool over the slot and drop the endmill gently on the bottom of the slot and continue cutting. If your careful the endmill will just touch the surface of the bottom of the slot. You can't bang it down, you have to carefully touch it off and then continue cutting. Of course that is done with the endmill not turning.

The reason for using the knee is you have more positive control and everything is rigid and you can keep the quill retracted into the head for more rigidity. When I am using the knee I like to extend the quill an inch or two but a lot depends on how heavy of cuts I am taking.

Of course when I am using a boring head I use the power feed on the quill with some drag on the quill. I do not use the power feed to drill with because it is hard on the feed system. They are not really designed for drilling with the power feed but some machinists do use the power feed for drilling.
It's only ink and paper.

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seal killer
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Post by seal killer » Fri Jan 01, 2010 2:01 am

Jack and Carl--

Jack, how stupid of me! Of course it is .250" per revolution. I pay so little attention--no! ZERO attention--to the knee crank that I did not even KNOW what it was after using it for so long!

Carl, using the quill, I have had great luck drilling copper, brass, and bronze. And, I have had great luck milling brass and bronze. (I have never milled any copper.)

However, I take your suggestions seriously and will give them a try, since I am a LONG way from being proficient in anything I do with the mill. It just seems to me that .250" per revolution does not provide anywhere near the precision obtainable with .100" per revolution. Still, I am going to try it.

I think the BP Series I quill diameter is 3.375". Although smaller than the Grizzly G3616 and G3617 (both are 4.00"), it is not THAT much smaller. In other words, the size of the G3616 quill does not support my contention that it is better to mill with the quill than the knee.

I wonder if my experiences, which are all shallow milling tasks of two inches or less and require no more than that quill extension, lead me to believe in using the quill instead of the knee?

I just can't see cranking that knee up during a milling operation with any precision. I am thinking fly cutter, face mill, and even an end mill.

I will give it a whirl and see what I get.

Thanks and Happy New Year!

--Bill
You are what you write.

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GlennW
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Post by GlennW » Fri Jan 01, 2010 9:07 am

Something for the milling in tenths on knee mill guys to consider.....

The perpendicularity (tram) of the spindle to the table can change when the knee is locked or unlocked or moved up and down.

It will most likely happen to a lesser degree, if at all, when moving just the quill.

Not to say it's a bad idea to have one on the knee, Just that
there is a good reason for more accurate machines to have quills or a vertical column on which the head travels, but not movable knees.

Having a secondary form of position indication other than the dials on both would be useful for better accuracy. Possibly just an adjustable slide with a 2" travel dial indicator on the knee such as some use on the lathe carriage would be inexpensive and useful when needed.

I have a machine that someone had installed a simple telescopic rod with a quill clamp, indicator, and a stop. It's quickly adjustable, accomodates the full quill travel with a 1" travel indicator, and is very useful.

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Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!

CarlD
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Post by CarlD » Fri Jan 01, 2010 4:14 pm

If your knee moves out of tram when you lock it you need to adjust the knee gib. The knee gib needs to be snug enough to eliminate side movement or frontal movement.

The wear on a mill ways will be the most on the X travel, then the Y travel and then the knee travel. Think about it. You want the knee as tight as reasonably possible and have smooth travel up and down. I seldom lock the knee but my mill is like new although about 25 years old. If you lock the knee you immediately enter an error in the tram of the head if the gib is not properly adjusted.

IF, you can move the quill down in exactly .0005" or .001" increments and lock the quill at that point then you could use the quill for DOC. However, most mills have no built in way of doing that and you would have to add a dial indicator or digital travel method of doing so. Even then it takes care to do so.

To move the knee is easy and the dial is marked. You can put a dial indicator on a mag base on the way area of the knee and use that to move the knee.

The fact is the knee is the most positive method of moving the work closer to the cutter. Once you lock the quill and never move it the knee is the boss of the DOC.

When flycutting you should never use the quill to change the DOC. Lock the quill and use the knee for all cuts.

You won't find many professional machinists using the quill to change the depth of cut, they use the knee because it is the most exact way.
It's only ink and paper.

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GlennW
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Post by GlennW » Fri Jan 01, 2010 4:34 pm

Lots of different circumstances and preferences.

Much depends on the operation being performed. I'll use both on the manual mill depending. I'll also occasionally set a quill depth stop and adjust the knee to the desired depth of cut, then raise the quill and use the quill to step feed to the final depth. The ability to raise the quill for gaging is also handy in some occasions.

I also have a CNC knee mill with a manual Z (quill), and it's all quill, as once you set the knee height you reference one tool and the rest are referenced accordingly for tool changes. Move the knee, and you loose all of your tool Z references.
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!

Harold_V
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Post by Harold_V » Fri Jan 01, 2010 5:00 pm

seal killer wrote:Carl--
The Z readout is in the knee because it's the best place for it.
I did not think the knee was the best place for the DRO. I could be wrong. My knee crank moves 0.200" per revolution. This is not good. It is difficult to get a "fine tune" at that rate. The fine down feed moves 0.100" per revolution, twice as good as the knee.
The one complaint I have with my Graziano lathe is the dial on the cross slide. It's relatively small, and moves the cross slide .200" per revolution. So then, a turn of the dial changes diameter by .400". The marks are almost touching, they are so close together.

Still, I turned out work with less than a thou tolerance, and did so routinely.

I think you'll come to realize that if you concentrate on the dial, you can make minor adjustments that permit working to tenths.

Trust the dials, Bill.

Harold

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