DTI Stand – Single Lock Type?

[Dr_GMJNParticipant @dr_gmjn]

All,

Can anyone recommend a DTI holder – the articulated type with a central locking knob that locks all three joints in one action?

Prices seems to range from about £20 (including a DTI ! ), to about £200 for a Mitotoyo item.

Obviously I want one with a high force switchable magnet, and high rigidity.

Thanks.

[Dr_GMJNParticipant @dr_gmjn]

[Henry BrownParticipant @henrybrown95529]

I have a hydraulic Dasqua from Chronos, mid price range but very good.

[Dr_GMJNParticipant @dr_gmjn]

Posted by Henry Brown on 06/01/2021 12:23:41:

I have a hydraulic Dasqua from Chronos, mid price range but very good.

Thanks Henry.

What's the reasoning behind it being hydraulic?

[Nick WheelerParticipant @nickwheeler]

I have the one pictured(or it's twin), and a couple of much smaller ones that were about £10 from ebay. The big one works perfectly out of the box; less than a turn of the knob locks it up tightly. The cheap ones now do the same after I took them apart and finished all the mating surfaces of the wedges properly.

So I would say it's more of a wedging action than hydraulic

[JourneymanParticipant @journeyman]

Beware the 15 quid ones from Amazon or similar. My review ***HERE***

John

Edit: Add Photo

Edited By Journeyman on 06/01/2021 13:42:15

[not done it yetParticipant @notdoneityet]

Magnetic bases, of various qualities, are available separately. You pays your money….etc.

[Henry BrownParticipant @henrybrown95529]

TBH I've no idea Dr! It does allow for a good feel when setting up if needed, unlike the clamp type which tends to be either clamped or not the hydraulic damping is there as required. Others here have Mitutoyo hydraulic but they are twice the price! I have to say it is very stable, I bought it for clocking on the mill, I use it under the head and sometimes on the quill/spindle so it needs to be stable. I have a conventional clamp type with a magnetic base for use on the lathe but much prefer the hydraulic!

One thing you might want to consider is the size of the base and arm, I have a Seig SX4 mill, its fine size wise for that, but may be a little large for smaller machines.

Edited By Henry Brown on 06/01/2021 14:02:50

[Clive FosterParticipant @clivefoster55965]

Not so sure about the need for a high force magnetic base. Much to be said for one that is strong enough to support the gauge with the arm at full stretch but still weak enough to let you slide it around on the table with a decent push. I have one I can fine adjust by a sort of levering rolling action of both thumbs. Easy to get a decently controlled few thou' shift.

Consider getting one of the inexpensive single lock arms off E-Bay and adding your own base. Unlike Journeymans experiences my £10 (ish) arm works well. The arms are shorter than the usual gauge mounting types and more in tune with the space available on our smaller machines. The one I got to carry the Bjur nozzle and vice alignment dial gauge on my Bridgeport is about 2 1/2 inches between pivots.

That said, for most purposes I loathe the single lock, articulated arm gauge carriers with a passion. The Eclipse post and pivoted arm ones I use for gauge mounting have a screw adjustment that is easily set to a thou or less.

Clive

Edited By Clive Foster on 06/01/2021 13:46:37

Edited By Clive Foster on 06/01/2021 13:47:32

[Gordon AParticipant @gordona]

Having bought a cheapie version of the type above to fit to an existing magnetic base, a quick strip down of the device revealed the method of locking the stand. I cannot however understand the principle of operation of the hydraulic type. Is there anyone out there who could enlighten me please?

Gordon.

[Dr_GMJNParticipant @dr_gmjn]

Thanks all.

I'm currently using a very large Eclipse base with a push-button magnet, fitted with a thick solid bar and a cast slider mechanism that holds the gauge arm. It has a worm-drive fine adjustment on the casting, which can very easily be zeroed, and is also rock solid when turning the DTI dial to zero. It is however very cumbersome when used on small machine tools, and the push-button very stiff to use.

I just wanted something smaller, and easier to adjust.

[Howard LewisParticipant @howardlewis46836]

Whatever you use, it must be rigid.

If the clock is waving about, even slightly, accurate measurement will be impossible.

My particular bete noir are the ones with a C shaped spring in the middle of one arm. I bought one but never use it, despite the ability to "fine adjust", because it is not as rigid as the old fashioned monkey blocks.

Howard

[Martin ConnellyParticipant @martinconnelly55370]

I have a Mitutoyo hydraulic one, works fine and good for positioning the indicator then locking it solidly in position. It is my go to mag base.

Martin C

[JezParticipant @jez]

I bought a cheap one and wasn't impressed – it moved about no matter how hard it was tightened.

So I bought a Noga. Fantastic bit of kit – solid as a rock. And the bottom adjust feature is excellent too – a much better place to adjust from than at the business end…

[Martin ConnellyParticipant @martinconnelly55370]

Thread on this topic from 2020 DTI stands

Martin C

[Oily RagParticipant @oilyrag]

Jez – These cheap mag bases 'move about' due to the fact the machined edges are not flat nor are they square to each other. I bought 2 similar to the one pictured by Journeyman in the toolmarket in Shanghai for £5 for both of them (knocked the seller down from just over £8 for the pair) I thought it was worth the money just to get the arms!

However, after transferring the arms to a more substantial Starret mag base I discovered the out of truth in the original base. Put it in the mill and trued it up and now it is quite a handy tool with the smaller base.

Martin

[OldironParticipant @oldiron]

I have a Noga and 2 cheap versions. The Noga is perfect as it should be for the price. The 2 cheaper items now work very well after stripping and fettling them.

regards

[Pete RimmerParticipant @peterimmer30576]

I just bought one of the cheap ones for £14. I wasn't expecting champagne taste for lemonade money so I found it quite adequate given the cost. The base sits flat and the magnet will hold a DTI and a 2" dial gauge with the arm at full horizontal extension, so I'm happy with mine.

[Bill PudneyParticipant @billpudney37759]

Cannot emphasise the need for rigidity enough. When I was re-setting up my lathe, initially the set up consisted of a good quality mag base and arm as shown above. It was extraordinarily difficult achieving repeatable results. So I made a rigid DTI holder, which eliminated the mag base and arm. Bingo!! Repeatable results. I'll see if I can find it and get a photo, it wasn't difficult or complicated.

cheers

Bill

[JezParticipant @jez]

Posted by Oily Rag on 06/01/2021 17:34:56:

Jez – These cheap mag bases 'move about' due to the fact the machined edges are not flat nor are they square to each other. I bought 2 similar to the one pictured by Journeyman in the toolmarket in Shanghai for £5 for both of them (knocked the seller down from just over £8 for the pair) I thought it was worth the money just to get the arms!

However, after transferring the arms to a more substantial Starret mag base I discovered the out of truth in the original base. Put it in the mill and trued it up and now it is quite a handy tool with the smaller base.

Martin

Hi Martin,

In my case it was definitely the arm which was moving… Paid more than £2.50 for it too!

Cheers,

Jez.

[Dr_GMJNParticipant @dr_gmjn]

Thanks Guys. I'm going to go with a Noga item for about £85. I'd done with buying tools that have to be fettled.

Obviously I'll keep the massive Eclipse base as well, just in case.

[EmgeeParticipant @emgee]

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

[Steve PaveyParticipant @stevepavey65865]

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!

[Martin ConnellyParticipant @martinconnelly55370]

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

[Dr_GMJNParticipant @dr_gmjn]

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?

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