Dro scale positioning

[ronan walshParticipant @ronanwalsh98054]

[ronan walshParticipant @ronanwalsh98054]

Just splurged out on a 3 axis dro kit for the Tom Senior. It seems that the way to mount the x-axis scale is to mount it on the rear of the table. This is going to reduce my meagre y-axis travel by an inch or so, which i don't really want to do. I was thinking of mounting it on the front of the table, but this would interfere with the limit switches for the x-axis power feed.

Anyone any novel ideas for mounting this scale without losing y-axis travel ?

[BazyleParticipant @bazyle]

How about a bellcrank to allow the scale to be mounted in the y direction.

[HollowpointParticipant @hollowpoint]

Could you use some L shaped brackets to mount it under or above the table?

Edited By Hollowpoint on 13/06/2019 17:51:25

[JasonBModerator @jasonb]

I suppose it depends on what kit you bought, a magnetic one need only loose you a few mm, even less if you mill out a slot for it in the back of the table with head to one side. Different case if its a standard size glass scale.

Edited By JasonB on 13/06/2019 17:55:05

Edited By JasonB on 13/06/2019 17:55:25

[Pete RimmerParticipant @peterimmer30576]

Posted by ronan walsh on 13/06/2019 17:22:11:

Just splurged out on a 3 axis dro kit for the Tom Senior. It seems that the way to mount the x-axis scale is to mount it on the rear of the table. This is going to reduce my meagre y-axis travel by an inch or so, which i don't really want to do. I was thinking of mounting it on the front of the table, but this would interfere with the limit switches for the x-axis power feed.

Anyone any novel ideas for mounting this scale without losing y-axis travel ?

I have mine hung on a 2" x 2" aluminium angle off the left end of the table. It took some fiddling with jack screws to get the scale straight and true but it's been performing well enough for the past few years. However, I am considering removing it now that I have heard about the stick-on magnetic scale as used on some ML7 cross-slides. I'm going to investigate if I can adapt this to the 300mm travel of my x-axis.

[JasonBModerator @jasonb]

As the limit switches don't need to be that rigid to work a micro switch what about putting the scale in an upturned aluminium channel fixed to the edge of the table and then fit the stops to that

[John HinkleyParticipant @johnhinkley26699]

At the risk of repeating what I've put in similar other posts, I overcame this problem by extending a milled bar beyond the scale on my VMC:

And:

The travel stops are retained, too. More pictures in my album.

John

[ronan walshParticipant @ronanwalsh98054]

Yes John, that looks like a solution, something i will consider when i get the dro kit delivered, I have enough movement in the x and z axis, but always found the y a bit limited and don't want to lose anymore if at all possible.

[Gary WoodingParticipant @garywooding25363]

I did something similar to John's solution on a friend's VMC mill.

[Mike PooleParticipant @mikepoole82104]

I looked at fitting a glass scale on the front of my VMC and found the crank handle fouls the scale when the table is fully forward. I have decided to use a magnetic scale on the rear of the table with a thin cover so only 2mm of movement should be lost. Machining a groove in the back of the table could be done and no movement lost.

Mike

[Gary WoodingParticipant @garywooding25363]

Mike

The conversion in my photo uses glass scales and no interference with handles has been encountered.

[ChrisBParticipant @chrisb35596]

Posted by JasonB on 13/06/2019 17:52:40:

I suppose it depends on what kit you bought, a magnetic one need only loose you a few mm, even less if you mill out a slot for it in the back of the table with head to one side. Different case if its a standard size glass scale.

Edited By JasonB on 13/06/2019 17:55:05

Edited By JasonB on 13/06/2019 17:55:25

Did you slot the table and insert the tape in the slot Jason? I 'm about to mount mine (which is similar) but I'm a bit concerned – the magnetic tape has double sided tape, so I was going to stick it directly to the table, but I don't know how long will it stay there when oil gets to it.

[ronan walshParticipant @ronanwalsh98054]

Got the dro kit delivered yesterday. Popped out to the shed today and had a quick look, i don't see any way to mount the scale on the front of the table. Looks like i will have to mount it on the rear and lose a bit of movement in the y-axis. There is simply too much going on, on the front of the machine, with the powerfeed limit switch, oiler, and the nut that clamps the table in place (its a universal).

[JasonBModerator @jasonb]

Chris, that's how they are coming out of the Sieg factory with the scale already fitted into the slot. Don't know if they use anything different to stick them or just DS tape. As you say if using something like paraffin or WD40 on ali then that may soften the tape adhesive over time if not protected.

[Mike PooleParticipant @mikepoole82104]

Posted by Gary Wooding on 14/06/2019 10:08:06:

Mike

The conversion in my photo uses glass scales and no interference with handles has been encountered.

That’s interesting Gary, my Warco VMC definitely fouls the knee raise crank handle with the table wound fully out and a glass scale fitted, they do make small changes over the years so maybe they changed some aspect of the knee raise crank handle or it’s position. Oh well problem solved with the magnetic sensor.

Mike

[Stuart BridgerParticipant @stuartbridger82290]

On my 2009 VMC, the knee crank handle will clout the edge of the table, when fully wound out, even without a scale fitted. My DRO has on optical scale fitted the rear of the table which was a Warco fit.

Edited By Stuart Bridger on 17/06/2019 09:28:28

[VicParticipant @vic]

From what I’ve seen traditionally VMC’s have the scale fitted at the back, even Warco do this if you order one with a DRO fitted. If you fit a compact scale you needn’t lose too much travel. On my particular VMC I lose about 20mm due to the vice overhanging the table anyway. This loss of travel hasn’t been an issue for me over the past ten years or so that I’ve had the machine.

[Clive FosterParticipant @clivefoster55965]

The main problem with mounting the scale, particularly glass scales, on the front of the table is clearance for the Y-Axis feed handle.

When I fitted the scale to the front of the table on my old Chester Lux / Rong Fu style square column bench mill I was able to find a suitable handle with a long centre spigot giving sufficient clearance for the scale. This was a disk wheel with folding handle style which actually stuck out less than the originals when the handle was folded in giving more room to move past without being tagged!

Alternatively you could simply replace the standard dials with a suitable hollow spigot having an extended end to take the handle thus moving it further back. With a functioning DRO system there seems little point in retaining the dials. If it does break you can always go back to standard.

I mounted my scale on standoffs leaving a slot to get at the stops behind the scale. It worked adequately but, in retrospect, Johns system with a bar in front would have been well worth the extra effort to make.

Clive

[ChrisBParticipant @chrisb35596]

Posted by JasonB on 17/06/2019 07:35:14:

Chris, that's how they are coming out of the Sieg factory with the scale already fitted into the slot. Don't know if they use anything different to stick them or just DS tape. As you say if using something like paraffin or WD40 on ali then that may soften the tape adhesive over time if not protected.

Ah, it came from the factory like that! Very nice of them, the most compact setup I've ever seen. I guess I will just take the chance and stick it with the double sided tape the scale comes with, and if it comes off in the future I'll stick it with some more permanent adhesive. Thanks Jason

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