vic008
Active member
Have shaft on bench trying to find the prop taper. Scribed a line for the shaft then for the taper. I come along 100mm from the intersection and measure and get 5mm. Why dont I get 10mm for the 10:1 taper?
Shaft taper?
- Thread starter vic008
- Start date
superheat6k
Well-known member
Are you measuring the diameter at both points, or the gap beneath a straight edge held on the non tapered part of the shaft, which would be the radius ?
coopec
N/A
Vic
I'm not sure that I am following you exactly. Maybe this Propeller Shaft Taper Calculator may help?
http://www.newmantools.com/tech/tapercalc.htm
OR
http://www.props.com.au/package/7.htm
Be sure to click "next" (bottom RH corner) for lots of other calculations.
Clive
I'm not sure that I am following you exactly. Maybe this Propeller Shaft Taper Calculator may help?
http://www.newmantools.com/tech/tapercalc.htm
OR
http://www.props.com.au/package/7.htm
Be sure to click "next" (bottom RH corner) for lots of other calculations.
Clive
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vic008
Active member
I find locating where the taper starts next to impossible. So I have like traced the edge/side of the shaft and then the edge/side of the taper on paper.
Spyro
Well-known member
What are you measuring? No shaft is that thin? Measure the diameter then move along a set distance say 100mm then measure again. If it's a metric diameter shaft it should have a 1-10 taper if imperial it should be 1-12.
vic008
Active member
Yes its a 1" shaft. Im doing the 100mm along and 10 mm in, but I get 5mm in. No calculating, and using a tape, straight edge, piece of 1" angle and pencil. Try it yourself and step up the 10mm and it just doesnt look right. Have asked 6 engineers so far and none have figured it out.
coopec
N/A
Obviously I'm not following what you are doing because I'm thinking the 5mm would be the radius and if you doubled it it would be the diameter (10mm).
I would have thought the online calculators would sort out the problem.
I give up!
I would have thought the online calculators would sort out the problem.
I give up!
Tranona
Well-known member
You need to measure the diameter at each point, not the radius which is what you are doing.
As suggested normally an imperial shaft is 1:12 and a metric shaft is 1:10, but not always. Fi
First though check the diameter of the main part of the shaft accurately with a micrometer. There is only 0.4mm difference between a 25mm and 1" (25.4mm).
What boat is it?
As suggested normally an imperial shaft is 1:12 and a metric shaft is 1:10, but not always. Fi
First though check the diameter of the main part of the shaft accurately with a micrometer. There is only 0.4mm difference between a 25mm and 1" (25.4mm).
What boat is it?
vic008
Active member
I have not measured the diameter or radius. If you go 100mm along then up 10mm youhave a 1:10 taper.right. For 1:12 taper you would go up 10mm over 120mm. Not hard to do on piece of paper. Using a bit of 1" alu angle am able to get a good represention of the angle for the taper .
rogerthebodger
Well-known member
The taper is the inclusive angle.
Tapering of the propeller shaft
All propellers in stock at TechProMax have the standard taper 1:10.
This means that the difference between the largest and the smallest diameter of the tapered hole represents 10% of the length of the propeller's boss (D-d=0.1 x L).
So if you are placing a straight edge on the parallel pare of the shaft and measuring the gap between the tapered shaft and the straight at 100 mm you are getting half the angle
As above it the difference in the Diameter along that distance NOT the difference in radius which is what you are measuring
Tranona
Well-known member
Rather than measuring angles just do as I suggest and measure diameters with a micrometer. Then you will know exactly what diameter your shaft is and the taper.
coopec
N/A
Hang on aren't you only looking at one side of the taper? Now go along and go down 10mm. Now you've got 20 mm? I'll have to sit down and do a drawing and it's getting late.
earlybird
Well-known member
My interpretation is that you are measuring the change of radius over 100mm. to give your 5 mm result, ie half of the change of the change of diameter, which will be 10 mm.
If it's a 1" shaft though, i'd expect 1:12 taper
If it's a 1" shaft though, i'd expect 1:12 taper
VicS
Well-known member
A digital vernier caliper will be precise enough, and easier to use on a taper, wont it? Certainly more precise than pencil paper and bits of Al angle. An analog vernier would be better or even a pair of ordinary calipers.
I thought all forumites had bought a digital vernier from lidl or Aldi by now!
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Tranona
Well-known member
Yes, makes life so much easier in many situations - and more accurate! In this case it would be a 30 second job to get the answer to both dimensions (accurately!)
coopec
N/A
A digital vernier caliper will be precise enough, and easier to use on a taper, wont it? Certainly more precise than pencil paper and bits of Al angle. An analog vernier would be better or even a pair of ordinary calipers.
I thought all forumites had bought a digital vernier from lidl or Aldi by now!
I bought my digital vernier on eBay (from China) for $A13 or about $US9.5. But for rough jobs I bought X3 plastic verniers for $A1.50 each
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ean_p
Well-known member
from the info you give;
Large D= 25mm
Small d=15mm (R12.5 -5 =R7.5 =15mm d)
This is a 10% slope with a cone angle of 5.72 degrees also known as a 1:10 taper.
The taper would be the same for imperial where in D=25.4 and d=15.4
Large D= 25mm
Small d=15mm (R12.5 -5 =R7.5 =15mm d)
This is a 10% slope with a cone angle of 5.72 degrees also known as a 1:10 taper.
The taper would be the same for imperial where in D=25.4 and d=15.4
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Lon nan Gruagach
Active member
Let me tell you what you are doing, so I can be sure I have it right.
You use blocks and angles and pencil to draw the outline of the shaft on the bench, namely you project the plan. You then measure the angle, as a ratio, between the side of the shaft and the taper.
What you should be doing is drawing both sides of the taper and measuring the angle between those.
Thats where all the talk of radius and diameter come in. Between the edge(parallel to the centre) and the taper will give radius, for diameter you need both sides of the taper.
Tapers could be measured by radius, but it is easier to get calipers on a diameter.
You use blocks and angles and pencil to draw the outline of the shaft on the bench, namely you project the plan. You then measure the angle, as a ratio, between the side of the shaft and the taper.
What you should be doing is drawing both sides of the taper and measuring the angle between those.
Thats where all the talk of radius and diameter come in. Between the edge(parallel to the centre) and the taper will give radius, for diameter you need both sides of the taper.
Tapers could be measured by radius, but it is easier to get calipers on a diameter.
vic008
Active member
No not measuring any angles. Am measuring 100mm from where the 2 lines intersect (thinking there it should be 10mm between) My method will give you an answer in a jiffy. Someone suggested I need to add the 5mm from the other side to give 10mm.. You are climbing a hill- you go along 10ft and up 1ft for 10.1
vic008
Active member
Ean-p I just measured that angle on paper and get more like 3 degree so I wonder do I need to double it
