Coaxial indicator

Hi Guys

With limited hight/clearance on my mill, I am looking to find a small coaxial indicator.

does once exist ???

were can I get one if possible

kind regards

Piero,

​Take a look at the Arc Euro website, I don't think they come smaller than those.

I have a picture of mine in use here at home, but my browser is not compatible with the Forum pages so if you want to see it in action you will have to send me a personal message [PM] with your email address for me to send it to you.

Regards
​Brian

Hi Brian

Thanks for the info,

I know of the Arc Euro type, I tad to large for me I am afraid.

need/want something smaller

The Haimer Centro might be slightly shorter, but it is significantly more expensive.

Andrew

Hi Piero, I made one myself. Can be very small and works great. See. http://madmodder.net/index.php?topic=3776.0. Best regards, Johan.

The Haimer Centro with the short probe is 92mm The Arc Euro one is 118mm WITHOUT ANY probe.

so the Haimer is quite a bit shorter, but as Andrew points out very much more expensive. I have the Universal 3D and it is around 115mm WITH the short probe. So big difference in lengths, and also in price.

Hi Johan, thanks for the link to details of your design/plans for the coaxial indicator, have put it to the top of the to do list.

Checked in your album expecting to see it pictured but none of the indicator but all of those engines and the EDM show you have been very busy, some superb work.

Emgee

This is how I do my co-axial centring:

Not quite as convenient as the real McCoy, it won't work if the hole is in a hole (if you see what I mean) but I can at least see the dial through the whole 360 degrees and it takes up much less head room.

Rod

There was an article in I think the Model Engineer recently that was a lever attachment that fastened onto the stem of a DTI .This would work for centreing holes on the mill.I can't find the magazine as I would have liked to make these attachments for myself.

Frank

If you have a DRO on your milling machine, you will rarely need a coaxial indicator. I can manage with just an edge finder and the "1/2" function of the DRO. Takes seconds to locate the centre of a hole with deadly accuracy and you can then store the coordinates as a local datum. The high cost of the Haimer should be justification for investing in a DRO - after all you will be saving money and it has many other benefits: win-win!

Speaking of DRO's - after acquiring my Bridgeport three years ago, I've finally got round to fitting a DRO! I've got the X axis fitted ok without too much head scratching on the back of the table out of the way of heavy vices and rotary tables and the like. Now determining the best way to instal the Y axis. I've the provision to put a Z axis later. So far so good. Looking forward to working more productively.

Johnboy25, Bridgeport Y axis scales are usually fitted to a bar on the right side of the knee, you may have existing holes. I used an aluminium bar approx 500 x 15 X 30mm, this was fixed to the existing holes, I made up 2 spacers from 25mm round stock and used shim washers to set the side of the bar true to the front/back movement of the saddle.The scales usually have elongated holes to allow setting of the vertical level. A pair of angle brackets are used to mount the reader.

Dave

Hi, Whenever I need to use my coaxial indicator, I remove the chuck, put in an MT3 collet of the correct size for the indicator, then install the indicator straight into the spindle collet and not in the chuck, and then centre everything up. Once done, remove the indicator, remove the collet and replace the chuck. I find unless you have a coaxial indicator with a humungous indicating lever, that the length of the indicator in the spindle, is around the same as the length of the chuck plus cutter so there is no need (or less need depending on how much Z you got) to lose Z alignment when switching between indicator and chuck. I use a standard blake coaxial indicator and a pretty standard Clarkson or ER32 collet chuck in an MT3 spindle nose.

This obviously works for my setup, but will depend on your coaxial indicator type and spindle nose as to whether it will work for you. Takes a bit longer, and is a bit fiddly, but if you dont have the clearance and you happen to have some spindle collets, then you may already have the solution infront of you.

Graham

Many years ago, about 1986 I brought one of these. http://www.blakemanufacturing.com/pages/aboutus.html

It is the coaxial indicator from the Blake manufacturing company in the USA. While not as accurate as a 0.002mm DTI, it is very fast for centering up a hole. With the spindle running you can quickly move the axis around till you get the least movement on the dial and get a zero position. I brought the carbide feelers for it early on and was glad I did. I run it at about 120 to 160 rpm, what ever is the closest on the belt arrangements or gear box. I found it to be particularly useful in horizontal work where it is difficult to see the other side of a DTI. The only downside is that they are a little long though. There was another brand available at the time, a little more shorter on total height, but was a lot wider and bulkier to handle.

Neil

Johnboy - it's a well trodden path and there are several ways to fit them. There are some pics in my album of how I did mine. Not sure which scales you have but the principle is very similar.

I also fitted my X scale on the rear of the table. I needed to fit a stop to prevent the scale getting squashed at full extent of travel. Very slight loss of movement but I thought it was better out of the way at the back.

I find the Z scale on the quill much more useful than the knee scale but I have both.

DRO was the best alteration to the BP - it transformed the thing and made my work orders of magnitude more precise.

Murray

Rod's solution is very ingenious and is also possible with this indicator holder I bought from Chronos...

**LINK**

The only issue with the Chronos version IMHO is that the shaft for mounting in the chuck is 8mm - not a standard end-mill size. So I sleeved it up to 10mm so that it fits one of my end-mill collets without me having to swap out the collet chuck for another.

Jon

ARC do something similar **LINK**

However, Muzzer's method really is easy with a DRO - plonk your edge finder somewhere in the hole and touch both sides using only the X axis and divide by 2 to get on the Y diameter, then repeat in the Y direction to get the centre. Why didn't I think of that? - I must be an analogue kind of guy, not digital . Actually, you don't even need a DRO, you can do the same thing using the micrometer dials on the X and Y axes .

I suppose, in theory, a rotating system eliminates any run-out of the probe held in the mill chuck but if the chuck is that inaccurate you're already in trouble!

Cheers,

Rod

Most mill DRO's have the centering feature built in.

Touch one side of the hole, I usually reverse the cutter in the R8 collet so I'm using the shank, and zero the DRO on that axis. then wind to the other side and touch off.

Press the 1/2 button and it divides by 2 and once you wind to 0.000 then that axis is central.

This type of indicator holder attaches around the spindle, so does not need fitting in a chuck, uses minimal headroom and is very adjustable:

They are a copy of one of the Noga mounts that Tom Lipton regularly uses in his youtube videos.

I bought one from the Bay for about £8.00 last year.

Edited By Zebethyal on 22/11/2016 12:23:27