Dial Indicators - what to get & where?

[Barking Mat]

I've been lucky enough to purchase all kinds of metrology equipment off members on here, dti's , micrometers, depth measures, and internal circumference thingies, for a fraction of the price of real world stuff, and I gladly thank all of you.

Don't be afraid to ask.

 

[ukracer]

Nogas are very reasonably priced.

Game changer IMO.

Plenty of copies out there though too that'd do just fine.

But you have to provide a link, or they don't exist.

 

[addjunkie]

Stern gland ?

Well yes...

Then there's the cutlass bearing, but I've never even considered a DTI.

It's an interesting point.

Maybe with a super tanker, or super yacht.

Many of us engineer folk over think many things.

With the big stuff its checked-at the build stage, and then face and perfiery method, in the old days, probably some fancy laser alignment malarky these days, optalign is the one Im familiar with.

 

[Barking Mat]

Many of us engineer folk over think many things.

With the big stuff its checked-at the build stage, and then face and perfiery method, in the old days, probably some fancy laser alignment malarky these days, optalign is the one Im familiar with.

I just twiddle the engine mounts till I see no visible vibration.

It's a bit of a rig-ma-roll when you change a motor, but it's not rocket science.

Flexible couplings are pretty forgiving.

But as I said, depends application.

I'm silly noddy boats, nothing big or powerful.

 

[TEO]

Etc...

https://www.amazon.co.uk/dp/B08PCVP2SZ/ref=sspa_dk_detail_3?psc=1&smid=A3Q2359RJ2EWPD

Yeah, it's a rabbit hole of measuring joy.

Thanks, almost exactly what I bought about 3 yrs ago. I use it but the dial's tiny & the quality isn't there. The stand's OK but the bracket's poor & gives who knows how much error. I bought what I could afford at the time but it's not something I trust & so, now that I can & have a job to do, it's time to get something better.

 

[Barking Mat]

Thanks, almost exactly what I bought about 3 yrs ago. I use it but the dial's tiny & the quality isn't there. The stand's OK but the bracket's poor & gives who knows how much error. I bought what I could afford at the time but it's not something I trust & so, now that I can & have a job to do, it's time to get something better.

What boats do you work with ?

Big / little ?

 

[addjunkie]

I just twiddle the engine mounts till I see no visible vibration.

It's a bit of a rig-ma-roll when you change a motor, but it's not rocket science.

Flexible couplings are pretty forgiving.

But as I said, depends application.

I'm silly noddy boats, nothing big or powerful.

Twidling the mounts on something with 30000 hp isnt a 5 minute job.

When you do some big pumps and compressors with gearboxes you actually slightly miss align to allow for thermal expansion.

 

[Barking Mat]

Twidling the mounts on something with 30000 hp isnt a 5 minute job.

When you do some big pumps and compressors with gearboxes you actually slightly miss align to allow for thermal expansion.

I'm in a world of 38 / 50 hp 'ness.

Depends application...

 

[TEO]

I should have said that the prop shaft's on a narrowboat, no flexi coupling. Not big or powerful but dialing out the vibration is proving v tricky... Making the adjustment with the engine under load is virtually impossible as I have to be **** up head buried in the engine while someone else steers while not standing on the deck that isn't there cos I've got it up to get to the engine mounts and on and on.
The problem was that one of the nylock nuts gave up on one of the engine mounts, I've replaced them all & its nearly there but just not quite. The stuffing box was leaking rather than dripping now it's closer to just dripping but it's letting in more than it did.
My plan is to get it as close as possible judged by the vibration, then put the indicator on the shaft so that I can get a visual on what happens as I wind the mounts up & down. Back&forth like that a few times till the vibes are back to normal then re-pack the stuffing box as the contents probably got ******** while the shaft's been wonky.....
At least that's the plan at the moment.

 

[Arc Tourist]

Got a feeling I'm lost in translation here ? Is the shaft connected to the engine/transmission and driven without a universal joint coupling ?

 

[tigdlo]

Sounds like you are looking to correct angular misalignment between the engine and shaft. When you said runout i assumed you ment a bent shaft. A magnetic base likely wont be your best option, best to make something that bolts to your drive flange.

This lug back Mitutoyo is £43.72 with shipping https://mqs.co.uk/mitutoyo-2046f-me...-100-remarks-l-h-r-c-lug-back-shockproof.html

 

[tigdlo]

Your shaft may also be over constrained, if there is a bearing either end of your stern tube then you should have a flexible coupling on the engine. it would still need to be aligned horizontally and vertically but would be less fussy about angular misalignment.

What is your setup?

 

[TEO]

In all honesty buying a noga base (or a good copy) is more important than the indicator which perches on the end.

Even cheap indicators will work for you but nothing beats a noga.

Moore and Wright 0-10mm Indicator Plunger Type MW400-05

0-10mm Moore and Wright Indicator - MW400-05

www.machine-dro.co.uk

M-SURE MS-410-012 Digital Indicator MS-410 Series 12.7mm (0.5 inch)

Large display plunger digital Indicator. Advanced functions include Cabled Data Output, ABS/INC. Data output: Yes

www.machine-dro.co.uk

Thanks that's an excellent link,

 

[Barking Mat]

I should have said that the prop shaft's on a narrowboat, no flexi coupling. Not big or powerful but dialing out the vibration is proving v tricky... Making the adjustment with the engine under load is virtually impossible as I have to be **** up head buried in the engine while someone else steers while not standing on the deck that isn't there cos I've got it up to get to the engine mounts and on and on.
The problem was that one of the nylock nuts gave up on one of the engine mounts, I've replaced them all & its nearly there but just not quite. The stuffing box was leaking rather than dripping now it's closer to just dripping but it's letting in more than it did.
My plan is to get it as close as possible judged by the vibration, then put the indicator on the shaft so that I can get a visual on what happens as I wind the mounts up & down. Back&forth like that a few times till the vibes are back to normal then re-pack the stuffing box as the contents probably got ******** while the shaft's been wonky.....
At least that's the plan at the moment.

I twiddle the engine mounts. Those rubber shock absorbers.

Don't forget they die too.

Approximately align motor to prop flange.

This must be done in the water, not out the water.

Then, with feeler gauges, adjust engine feet, to the best you can.

It's the engine feet which align the motor to the prop shaft.

 

[Barking Mat]

It's the engine which will be out of true, not the prop.

 

[Barking Mat]

Any issues fire away. Been there, done that.

You really don't need a dti on a narrow boat.

 

[Barking Mat]

Is the prop shaft straight ? That won't help.

If you've had propellor trauma, and the props not straight, you'll never get rid of vibration.

How's the propeller, same story.

So many variables.

Cutlass bearing, how much play ?

 

[Barking Mat]

Ask me how I know*

 

[Lewis_RX8]

Many of us engineer folk over think many things.

With the big stuff its checked-at the build stage, and then face and perfiery method, in the old days, probably some fancy laser alignment malarky these days, optalign is the one Im familiar with.

We got some training on the SKF kit very impressive

Mounts on shafts then the two lasers do most of the work for you , you just need to rotate as it tells you

Taking readings where it needs

Then spits out the shims needed and where

 

[Barking Mat]

I should have said that the prop shaft's on a narrowboat, no flexi coupling. Not big or powerful but dialing out the vibration is proving v tricky... Making the adjustment with the engine under load is virtually impossible as I have to be **** up head buried in the engine while someone else steers while not standing on the deck that isn't there cos I've got it up to get to the engine mounts and on and on.
The problem was that one of the nylock nuts gave up on one of the engine mounts, I've replaced them all & its nearly there but just not quite. The stuffing box was leaking rather than dripping now it's closer to just dripping but it's letting in more than it did.
My plan is to get it as close as possible judged by the vibration, then put the indicator on the shaft so that I can get a visual on what happens as I wind the mounts up & down. Back&forth like that a few times till the vibes are back to normal then re-pack the stuffing box as the contents probably got ******** while the shaft's been wonky.....
At least that's the plan at the moment.

The engine doesn't have to be under load, at all.

I do it engine off, in neutral.

Whether it under load doesn't change anything. Will accentuate, propellor trauma giving false readings.

You're looking for the concenrticity (maybe not the right word) of the prop, to the alignment of the output flange on the gearbox.

When the prop is correctly aligned flush to the gearbox, you've won.

Vibration after this is caused by bent prop shafts, or bent propellers, or both.

Expect some play in cutlass bearings.