PDA

View Full Version : Coax Indicator question



sconisbee
02-11-2008, 07:59 PM
How many here have and use them? I was pondering buying a new toy and was wondering just how usefull they are and how quick to use they are, i figure for rough lining up bores they gotta be handy and quicker than more traditional methods right?

IOWOLF
02-11-2008, 08:03 PM
Wouldn't be without mine.

Your Old Dog
02-11-2008, 08:05 PM
You probably know a lot has to do with whether or not you own a mill/DRILL. In which case, you have to raise the head to fit the coax indicator and when you do the head flops around. I don't think it would be of any value on a mill/drill with round column.

sconisbee
02-11-2008, 08:09 PM
YOD yea i wouldnt think one would be usefull on a mill/Drill, i gots me a Gate Profitmill which is yer typical tiwanese(sp) bridgy clone:rolleyes:

I do a fair bit of work that requires locating from existing holes/bores and i noticed one in a catalogue the other day thought it might be kinda handy.

And damn you and IO are quick! lol i only posted like 3 minutes ago!

mochinist
02-11-2008, 08:19 PM
Once you have em figured out you can indicate a hole in way less time than using an indicator and a indicol style holder, they are well worth the money. They are also easy to make for the make it yourself guys, seen plans before on this site, and if I remember right one of the bedside reader books has a plan for one also, I forget which edition though.

On a side note, it surprises me how many guys I see using them manually, screw that, put the mill in low range turn it on and hold the driving rod with one hand and adjust the x and y handles with the other till you have no runout.I have double checked mine and the hole position is always within .0005", usually closer, so it is fine for more than rough lining up if you ask me.

Carld
02-11-2008, 08:28 PM
I have one and use it a lot. I use it at slow speed in the mill and by hand depending on what I am doing.

I also made a split sleeve to use in my tailstock chuck so I can dial in a shaft in a steady rest with the coax in the tailstock chuck. It's tricky to do but works.

I like coax indicators.

JCHannum
02-11-2008, 09:44 PM
I have a Blake and use it frequently. If you do buy one, save your money for a Blake, the knockoffs are not as good, I have yet to hear of anyone who has been satisfied with them.

I have also made a couple of the Lautard versions, he copied from an article in HSM. John Stevenson also made one, and they are fun and simple to make, but the Blake is still better.

jcarter
02-11-2008, 10:03 PM
I just recently got one. Now I wonder why I didn't get one a long time ago. It's so much easier to use than a DTI where the dial turns 360 deg.Mine isn't a Blake but I am happy with it. I have checked it against my DTI and it's within about 2 tenths as best as I can tell with my failing eyes. Better than my capabilities are.

mechanicalmagic
02-11-2008, 10:28 PM
Can't add anything except another YEA for getting one.

Oldbrock
02-11-2008, 11:15 PM
Shows how long I've been out of the mainstream hiding away in the mountains of BC Canada I honestly didn't know these existed. Just went online and bought one. I've always used a regular indicator with a mirror. Some performance. Thankyou for bringing up the subject. Just how long have these been available? Peter

sconisbee
02-12-2008, 07:16 AM
Well thankyou for all the replies, looks like a resounding yes to getting one:D

They seemed a good idea but i wasnt sure if they were more of a gimmick like some things are, but it sounds like they are infact a really usufull tool. ofcourse i didnt even think about using one in the lathe for centering, well one is just about to go on my shopping list:D Thanks again!

John Stevenson
02-12-2008, 07:58 AM
Good idea but hard to use.
No hard as in hard but time consuming.
I know I'm going to get flack over this but those damn things are 6" to 8" long, so you remove the tool you are using, wind the table down, fit the co-ax, wind up, set centre, wind down [ yawn ] remove co-ax, wind up [ nuther yawn ] refit tool.

And remember on a Bridgy or any machine with a nod and tilt head unless trammed correctly it's only accurate at the Co-ax indicator distance from the chuck.

Yes I did make one, used it about 5 or 6 times then realised there is more to life than winding handles.


.

japcas
02-12-2008, 09:51 AM
I agree totally with John Stevenson on this one. I got tired of cranking the table or head up and down. I use a regular indicator and set it right above the hole. Then I visually center it with the hole by turning the spindle. When it looks like it is traveling with the hole, I drop it in and indicate the hole. With practice you can train your eye to be very accurate and most of the time the spindle will be within .010 to .015 runout at the most. Just takes a second to dial it in from there. Whole process takes less than 2 to 3 minutes.

One other thing to consider when using a coax indicator. Unless used in a collet with no runout they won't be accurate. With a regular indicator it doesn't matter if you hold it in a jacobs chuck with some runout because the indicator is traveling with the spindle. But the accuracy of the coax indicator is directly related to how true it turns with the spindle. Any runout it has with the spindle will affect how close you will be able to line the spindle up with the hole.

hitnmiss
02-12-2008, 10:09 AM
I got a cheaper Enco one. Works fine but my mill has 5" of spindle Z... By the time I crank the knee down and back up I could have had the hole located with my dial indicator.

Used mine twice.

Carld
02-12-2008, 11:56 AM
Mine came with short feelers and I use them most the time. I only use the long feelers in large or deep holes where needed.

I don't have to run my table knee up and down a lot. In fact, I seldom have to move it.

John, japcas, ahhhh, did you think to try the short feelers or were they missing from your set?

sconisbee
02-12-2008, 12:44 PM
maybe i should add a powerfeed to the knee to my wishlist:D gotta admit didnt really think about the knee cranking part, i might still get one if i see one cheap enough. I suppose its one of those its handy for some things but a pain in the ass for others:rolleyes: Still it is another funky tool to add to the collection:D

mochinist
02-12-2008, 12:46 PM
Eat your vitamins and crank the handle, its good exercise. Surprises me how many machinist whine about cranking a handle.

Peter N
02-12-2008, 12:50 PM
I bought a new one from e-bay for 60, an LTL I believe, as it's identical to that one in the J&L catalogue.

Like Carld mine has long and short probes, and doesn't need any more headroom to put in the spindle than an R8 collet would take.
I don't even power up the spindle when I use it, just twist the drawbar with a spanner in one hand, and adjust the table with the other.

It's really very quick to use.

Peter

Edit: Just spotted this on e-bay (US). It's the same one that I have, but cheaper (except for shipping at $34)
http://cgi.ebay.co.uk/CO-AX-INDICATOR-MILLING-MACHINE-NEW-CASE-COAX-0005_W0QQitemZ330210002154QQihZ014QQcategoryZ58239 QQrdZ1QQssPageNameZWD2VQQcmdZViewItem?_trksid=p163 8.m122

sconisbee
02-12-2008, 01:04 PM
Eat your vitamins and crank the handle, its good exercise. Surprises me how many machinist whine about cranking a handle.


Ohh i dont mind cranking the handle....im just lazy so prefer the quicker options lol!:D Having said that just found and bought one on ebay, i thought for 40'ish it wasnt a bad price, and appears to be the one from the J&L catalogue, but only time will tell....

speaking of J&L while i was flicking through the indicators i noticed the Tesa Techonologies stuff, i'd noticed them before and not really paid much attention, but today i noticed the big Swiss made mark by them all, so anyone here used tesa stuff? i normally prefer mitytoyo but the Tesa stuff seems a fair price, specially for their non digital mic sets.

Edit: ahh thats the one I just bought! found it bout half an hour ago while browsing. Thanks for letting me know anyway tho cause i suck at noticing things on ebay:D

japcas
02-12-2008, 01:10 PM
I've seen used different length feelers but still prefer to use a regular indicator. I don't mind cranking on the handles either but if I can get around it I will. It all comes down to preference.

Oldbrock
02-12-2008, 01:31 PM
Regarding Tesa. Ive had Tesa mikes and indicators for too many years to count and they are always perfectly accurate and reliable. My 0 to 1" mike cost me $17.00 new so you know how long I've had it. No one is allowed to touch my Tessa tools. Peter

pcarpenter
02-12-2008, 03:39 PM
Isn't Tesa a Brown and Sharpe brand? I don't have their catalog at hand, but I believe its their stuff.

Paul

sconisbee
02-12-2008, 03:50 PM
Isn't Tesa a Brown and Sharpe brand? I don't have their catalog at hand, but I believe its their stuff.



Hmmm im not sure, J&L sell both B&S and Tesa seperatly and Tesa is more expensive than the B&S... I'll see what i can find out.

John Stevenson
02-12-2008, 04:18 PM
Bought one of the J&L Tesa micrometer 0 - 30mm, yes I know funny size but for motor work it was brilliant.

Worked very very accurately until I dropped it then the display went pear shaped.
It was 99 on offer for about 45, contacted J&L and the repair charge was 99.

Bummer but it was my fault, just wary now of spending this much again.

.

S_J_H
02-12-2008, 04:33 PM
One other thing to consider when using a coax indicator. Unless used in a collet with no runout they won't be accurate. With a regular indicator it doesn't matter if you hold it in a jacobs chuck with some runout because the indicator is traveling with the spindle. But the accuracy of the coax indicator is directly related to how true it turns with the spindle. Any runout it has with the spindle will affect how close you will be able to line the spindle up with the hole.

Holy smokes I never considered this! I could get my import co-ax dead on and then recheck with a DTI and the DTI always showed an error with the co-ax readings. It just never clicked that light bulb on in my head why.
Otherwise I think a co-ax is super fast to use on my little cnc mill. But the gauge installed in mine(import) is a total POS.

Steve

sconisbee
02-12-2008, 05:59 PM
Bought one of the J&L Tesa micrometer 0 - 30mm, yes I know funny size but for motor work it was brilliant.
Bummer but it was my fault, just wary now of spending this much again.


I was thinking that, i wonder why they chose 0 to 30mm. A lot of the Tesa stuff seems favorably priced next to Mitutoyo which is what i normally would choose, but the swiss made peeked my interest, might just buy Tesa next time i need measurement stuff.

lane
02-12-2008, 07:11 PM
Good idea but hard to use.
No hard as in hard but time consuming.
I know I'm going to get flack over this but those damn things are 6" to 8" long, so you remove the tool you are using, wind the table down, fit the co-ax, wind up, set centre, wind down [ yawn ] remove co-ax, wind up [ nuther yawn ] refit tool.

And remember on a Bridgy or any machine with a nod and tilt head unless trammed correctly it's only accurate at the Co-ax indicator distance from the chuck.

Yes I did make one, used it about 5 or 6 times then realised there is more to life than winding handles.


.
I agree with Sir John. You use your coax and I will use my best test indicator and indical ,and will be making chips before you even get a tool in the collet . just clamp indical to mill spindle never take tool out of holder

mochinist
02-12-2008, 08:20 PM
I agree with Sir John. You use your coax and I will use my best test indicator and indical ,and will be making chips before you even get a tool in the collet . just clamp indical to mill spindle never take tool out of holderI have a few bridgeports at work, anytime you're in AZ I'll gladly take that bet.:)

Carld
02-12-2008, 09:48 PM
Yes, I have used almost any type of indicator in a mill you can think of and nothing is as fast as a coax indicator. I too would like to chalange Lane as well.

japcas, one of the reasons a coax is so good is it don't have to run true to indicate work in. You can use a drill chuck with lots of runout and it works as well as a collet that has "0" runout. I just went to the shop to test it before I posted to be sure since I have been retired for 4 years and haven't used mine but once since then. I purposely shimed it out of true to do the test and with the coax wobbling I had two thousands runout. I then ran it in a true running 3/8" collet and I had two thou. runout. Fortunatelly I am boring a hole and had work set up in the mill. The hole is roughed out right now so I'm sure the runout is in the work piece.

I have used coax indicators for years and they are fast and accurate and you can "0" the work with the spindle running. You sure can't do that with any of the other indicator methods. Also, the face of the coax indicator is facing you at all times unlike any other dial indicator method where you have to look around front, back and sides to see the indicator face.

As said, everyone has their favorite way to do something but don't post a false statement about a method.

oldtiffie
02-13-2008, 06:23 AM
One other thing to consider when using a coax indicator. Unless used in a collet with no runout they won't be accurate. With a regular indicator it doesn't matter if you hold it in a jacobs chuck with some runout because the indicator is traveling with the spindle. But the accuracy of the coax indicator is directly related to how true it turns with the spindle. Any runout it has with the spindle will affect how close you will be able to line the spindle up with the hole.


Holy smokes I never considered this! I could get my import co-ax dead on and then recheck with a DTI and the DTI always showed an error with the co-ax readings. It just never clicked that light bulb on in my head why.
Otherwise I think a co-ax is super fast to use on my little cnc mill. But the gauge installed in mine(import) is a total POS.

Steve

Thanks japcas and Steve.

That quote of japcas's stopped me in my tracks as I might have considered getting one up until then.

My thoughts were similar to Steve's.

So, taking japcas's post at face value, it seems that when the co-axis indicator (CAI) is mounted in a collet (other options such as drill chucks are not sufficiently accurate) that a Dial Indicator (DI) must be run on the CAI shank to see that it is running very true.

If it were not running true it seems that another similar collet is needed and so on until the CAI shank runs true.

What happens if there is not a sufficiently accurate collet?

Is this right?

If so, I'd have to ask why a CAI is used at all as the DI is already on the mill/machine ready to go.

I have no problems with a Dial Indicator as I use a mirror to read it. Takes a bit of practice but once learned/mastered it is very good.

I am not interested in speed of set-up (or of anything else either for that matter) - but a DI does the job for me.

I have a range of attachments so that I can set the mill head to where I want to use it for machining so that I don't have to dial the machine/job in only to have to move the mill head/quill etc.

Carld
02-13-2008, 09:46 AM
I will repeat: A coax indicator does not have to be in a perfect collet or chuck to be accurate.

You can have it wobbling in a chuck and it will indicate accurately.

You can have it in a defective collet with run out and it will indicate accurately.

Have I made myself perfectly clear.

What part of these statements do you not understand?

JCHannum
02-13-2008, 10:08 AM
Carld, that is quite correct. It functions in exactly the same way as a wiggler in that it locates the center of revolution.

They also take little room to remove & install, the total length of the body plus shank being 5-3/8". The probe can be installed after the indicator is in the machine.

The speed of use will depend on what you are used to using, a DTI can be used with speed, but I find using a mirror cumbersome and don't resort to that unless absolute dead nuts accuracy is required.

The imports work pretty well, but do not hold up as well as the Blake. If you search the PM forum, you will find several posts on the subject, the concensus is you will eventually spend the equivalent of the cost of the Blake buying replacement imports.

Orrin
02-13-2008, 10:58 AM
Just about everything about a co-ax indicator has already been mentioned except for one thing:

Chuck one in your lathe and use it to center the tailstock. Not only is it quick and easy, it will tell you if your tailstock is at the correct elevation.

Orrin

japcas
02-13-2008, 12:26 PM
Carld, I stand corrected. Somewhere along the way I got it in my head they needed to run true to be accurate. I've used Blakes and I have an import, and like JCHannum stated, most people will probably spend more than you would for a Blake trying to get a good import. Mine was crap straight out of the box.

Carld
02-13-2008, 12:30 PM
Good idea Orrin. That would get you in the ball park to "0" it in action just like I use it in the tailstock to rough in the work in a steady rest and "0" it in use.

macona
02-13-2008, 03:56 PM
I have a blake, had it for a year, used it twice. Meh...

My Interapid with a indicol works just as well.

Really ought to sell that blake.

Carld
02-13-2008, 03:59 PM
Put a price on it. I would bet it would sell real fast in this thread.

Spin Doctor
02-13-2008, 04:39 PM
I've got a Blake, but before that I had a knock-off. The knock-off was a POS. But even the Blake I don't trust to be any closer than .0005. Good enough for most stuff but not everything. But I can tell you one thing NOT to do with a CO-AX. A guy I worked with had to indicate a multispindle drill head in to a parts holding fixture's bushing plate. Well he had the bright idea to put the Blake in the spindle and have the head fired up. Drill head ran at 2 or 3 thousand RPMS. KABOOM. The guts of the Blake lunched all over the place. Then he did it again. After the second one blew up he was bitching about what a crappy POS the CO-AX's were. Then somebody told him about the 500RPM speed limit

Oldbrock
02-14-2008, 12:23 PM
SPANNER Ah Peter, haven't heard that used since I left the old sod in 1954 (Lived in North Wales) Peter(yes, another one)

Wirecutter
02-14-2008, 01:01 PM
I got a CAI as a gift before I even knew I needed it. It's an import, so it's not the best, but I use it a lot and love it. Judging from the comments here, I guess I shouldn't use it for brain surgery or building nuclear weapons.

-Mark

macona
02-14-2008, 03:06 PM
OK, 1 blake for sale, standard kit. Near new. $135 plus shipping.