Which dial Indicator for aligning the tranny with prop shaft

[carlspackler]

I will be aligning my transmission and engine in a few weeks. The instructions show a dial indicator. I see them for sale on eBay for 30, 40 fifty dollars.

I'm not terribly worried about getting this right but a dial indicator would help put my mind at rest. It's a new engine so the alignment will be from scratch.

Has anyone used a dial indicator to check the alignment, runout etc? If so what model?

This is a one inch bronze prop shaft on an 89 Catalina 30 mating to a beta 20 Twin Disc/TMC gear box tranny using a split coupling and vibration dampener.

[NoTies]

You're going to struggle having enough room to use a DTI for alignment, they need a lot of swinging room. Feeler gauges are what you need.

[Steve Bean]

You're planning to do this when the boat has been in the water for some time, right?

[UNCIVILIZED]

Listen to the above, as the boat will change shape a little once it's in the water. And on gauges, I'm no authority, but what about a runout gauge? See here's the thing though. There are a number of mating surfaces in between the engine's output, & the prop shaft. And even with a runout gauge, one or several of these could be excessively out of spec' & not have said gauge tell you this.

Where as if you measure the alignment between the transmission's output, & adjacent shaft mating surface with feeler gauges, then things should be "close enough". Though a dial/runout gauge might tell you otherwise. Even if for something as simple as the shaft being a tiny bit out of round, or slightly warped/bowed.

[foufou]

How much does the shaft sag from its cantilever from the cutlas bearing? How might we compensate for that?

don't believe everything you think

[boatman1]

Feeler gauges or slips of paper are the tools to use. I've found that you can "tap tune" as well, striking lightly around the circumference of the flange (obviously one performs the alignment sans flexible coupling) as you wrestle the engine around seeking the proper fit: the tone/timbre of the sound of the tapping changes as "perfect" alignment is approached, from ringing to flat. You"ll want to confirm with the feeler gauge, but in a sailboat it's frequently more difficult to manipulate the feeler gauge than to strike the flange with your (preferably bronze) hammer.

[Cadence]

Originally Posted by carlspackler

I will be aligning my transmission and engine in a few weeks. The instructions show a dial indicator. I see them for sale on eBay for 30, 40 fifty dollars.

I'm not terribly worried about getting this right but a dial indicator would help put my mind at rest. It's a new engine so the alignment will be from scratch.

Has anyone used a dial indicator to check the alignment, runout etc? If so what model?

This is a one inch bronze prop shaft on an 89 Catalina 30 mating to a beta 20 Twin Disc/TMC gear box tranny using a split coupling and vibration dampener.

If you can pick up a dial indicator with a magnetic base great if you have room. A set a feeler gauges an the ability to grow back the hair you will be pulling out. Just remember you are dealing with a three dimensional job.

Best of luck.

[Cheechako]

Originally Posted by NoTies

You're going to struggle having enough room to use a DTI for alignment, they need a lot of swinging room. Feeler gauges are what you need.

I agree with this. Just too cumbersome down there to add much to the process.

[Cheechako]

Originally Posted by foufou

How much does the shaft sag from its cantilever from the cutlas bearing? How might we compensate for that?

don't believe everything you think

How much does it hang out? How much does the coupler weigh? If a foot or less I would say it's inconsequential.

[dick sargent]

I've used feeler gauges for 50 years to adjust to .001" gap but .003" is supposed to be acceptable. Btw Sounding by hammer tapping sound intriguing. Never too old to learn...That's why I like this site.

[Squanderbucks]

Feeler gauge is what you want for aligning shaft and a dial indicator is useful when checking propshaft for being bent when out of the water. I have found that magnetic base dial indicators are of little practical use on boats - what you want is one that has the flexible arm attached . It clamps onto a solid surface that is convenient with a Vise-Grip that is built into the other end of the arm. Checking runout at prop usually can clamp to the rudder or strut and inside the boat even more places available when needed there.
You just need feeler gauges as everyone has said for the alignment you want to do. If way out of align or installing new shaft best to do out of the water. Then double check once it is back in the water.
Leave the bolts in the coupler in place - just back off the nuts enough to give a little play. They will support the shaft and still allow the flanges to move showing where the gaps are - top - bottom- sides.
Just don't adjust more than one engine support at a time - that will drive you crazy. Check with feelers after every change to the engine supports.

[seabreez]

Originally Posted by carlspackler

I will be aligning my transmission and engine in a few weeks. The instructions show a dial indicator. I see them for sale on eBay for 30, 40 fifty dollars.

I'm not terribly worried about getting this right but a dial indicator would help put my mind at rest. It's a new engine so the alignment will be from scratch.

Has anyone used a dial indicator to check the alignment, runout etc? If so what model?

This is a one inch bronze prop shaft on an 89 Catalina 30 mating to a beta 20 Twin Disc/TMC gear box tranny using a split coupling and vibration dampener.

I have aligned many shafts from 1" to 2 1/2" and have never used a dial gauge... always used a feeler gage and a hammer to tap the flange in to touch and measure. For a new installation... prepare some shims made of sheet metal... (thin) and some heavier metal. You will have to measure top and bottom and sideways also for a new install. (the learning curve)...

[sk Barnett]

At the risk of speaking out of place here, I will suggest that alignment of shafts involves: (i) parallel shaft end gap -- this is your feeler gauge; (ii) vertical alignment; and (iii) horizontal alignment. For the latter two a Last Word Indicator is generally used, particularly in tight spaces. You need room to rotate one shaft 180 degrees with the indicator resting on the stationary shaft to measure eccentricity or run-out. Last Word Indicators generally come with a magnetic vee-block mount, but alternative means of fixing the indicator to one shaft (like a hose clamp on a rigid bar) may be employed as necessary. Getting the engine/transmission assembly positioned left to right and vertically can be approximated using a straight edge and a bright light to see the gap will approximate the alignment, but final adjustments call for the Last Word Indicator in my humble view.

Kind Regards,

Steve Barnett

[topmast]

If the coupling /spine end of shaft has been done right on a lath you stand a good chance of proper alignment with a feeler gauge and patience. When you got it good,turn the shaft 180 and check again. Carefull not to leave the engine rocking on 3 legs .(easy to do)

[Suijin]

Just some caution about the shaft and the coupler. I'm assuming you're getting a new coupler from Stanley with your engine and it's going on the old shaft. Make sure that you get it on perfectly perpendicular or you'll drive yourself crazy after that. It can even be worth it to take the shaft and coupling to a machinist and have the coupling faced on the shaft for a perfect fit.