DTI Stand - Single Lock Type?

I see you have decided on a good quality tool but my experience using an £11 single operating point 2 armed mag base has been favourable for the cost and adequate for a quick check on concentricity of parts fitted in the chuck, only a small unit so easy to fit on the toolblock,

Emgee

Like OldIron I have a Noga and two cheap ones. The Noga is excellent, and the cheap ones ok after taking apart and polishing the bits that matter.,But, as I found out, if you overtighten a cheap one it breaks at the joints. So one of my cheap ones has a new limb, turned from brass - a completely uneconomic repair for something that only cost £12!

Gordon A, since you asked and no-one has answered I will tell you how the hydraulic ones work. The answers is just like car brakes. Instead of the foot pedal you have a piston pushed by the screw in knob. This pressurises the oil in the arm which in turn pushes on pistons that squeeze down on the swivel joints to lock them. The use of a small area on the pressurising piston and a larger area on the braking piston allows high pressure and solid locking. If the oil weeps out over time you can unscrew the knob to add a bit more as required.

When there is no pressure my Mitutoyo is very floppy, when pressurised it locks solidly. Between these extremes the arm stiffens up gradually to allow positioning, just like progressive braking with car brakes. The Mitutoyo I have has the knob at the base end, the Dasqua ones have theirs in the middle but otherwise I expect they work in a similar way.

Martin C

Does anyone have any thoughts on the best fine adjustment position?

The adjuster on the base would seem to possibly reduce stiffness a bit, just where you don't want it (suppose it depends on the method of adjustment), and when using the type with an adjuster on the DTI holder, you can sometimes affect the reading when you touch the adjuster.

I'm not sure if the Noga designs are stiff enough such that neither of these are particular issues?

I would wait until you have the new unit to find out if you need one or not. I tend to set the arm on mine to about mid point of the dti travel then set zero with the bezel.

Martin C

Not long after I started out with funds at the time in short supply I paid £15 for the one pictured, the price included the test indicator. Thinking if it was half decent I could get by with it until I could afford better, well I have probably been lucky but I cant fault it. The big surprise is how good the test indicator is, I tested it against my more expensive dial gauge and it is good throughout its range. It has no stickiness, very smooth and always returns to exactly the same position which cant be a bad sign.

The magnetic base is fine with a good pull on the magnets and the central locking is good and secure and the swivel joints look to be well made with nothing feeling fragile about them. So if it continues to perform as it is then I dont feel the need to spend a lot more on something that wont offer anything more.

As mentioned I was probably lucky in getting a really good one.

Ron's indicator and mag base now £13-79 delivered, such a good buy.

Emgee

Here's my £2.50 bargain:-

No manufacturer information on the box just the part ref. NF 2020 (probably the year it is expected to last too - but still going strong)

And here is the 'correction' I had to do to get it to stop rocking:-

I really don't know how they can do it for the money. Cost of the materials must be more than I paid for it.

Martin

Edit: the Mercer 0.0001" per division clock was NOT included!!!

Edited By Oily Rag on 08/01/2021 12:54:13

Thanks all.

I know there are bargains out there, but it seems the luck of the draw whether they're any good. I'd rather just get something that I know will be good to go from the start.

So to Martin's point - the Noga fine adjusters can be bought and added later?

I bought a Noga some years ago - it has given sterling service right out of the box, still silky smooth the price is long since forgotten.

I was fortunate though, my local supplier just happened to have them on sale the day I went in to look for a DTI stand.

Clive

You are better off without the fine adjustment. It is just one more potential point of flex or movement in the train. If you want maximum accuracy leave it out. The moveable bezel on the dial gauge is your fine adjustment without adding to the flexibility of the holder.

Agreed, but that’s assuming the arm it rigid enough to not be disturbed by turning the dial. I’ve got a cheap stand where turning the dial to zero is pretty much trial and error. If the arm Itself isn’t rigid, I’d think an adjustment at the base (eliminating touching the dial or arm) would be best.

Im assuming that with the Noga arm and base that this is a non-issue.

Bottom. All day long. Used both - bottom wins hands down...

I treated myself to a Noga and it is a nice tool. Stefan Gotteswinter did an interesting item on rigidity and produced a very solid stand.

https://youtu.be/37TLOf3GWwM

Mike

Edited By Mike Poole on 09/01/2021 19:24:58

Just to complete the thread - I decided on the Noga FA1120, with base adjustment:



It's as I'd hoped (and expected for the price) - Just the right size, rock solid, and the clamp and adjuster are very effective and smooth to use.

Thanks all.

Hi

I read this thread and saw the feedback on the cheap-as Chinese base and arm. I went out and stoned the important mating surfaces. It made a significant improvement to the feel of the motion. Probably not as good as a Noga, but good enough.

As a side note, I know there is often a lot of bad opinion of Chinese made stuff. I buy a lot of stuff off Aliexpress, and my experience is that price is a good indicator of quality. If you pay more, you get more.