Help! Non-standard taper, in the lathe spindle.

[Sergei Slovenija]

I thought I had MT5, but in fact, it's something else. Lathe chuck of the old American standard, long L1, as far as I remember. The question is, what is the cone? The measurements were carried out on an old worn cone, inherited from a lathe.

 

[Brad93]

With the Long Nose tapers, they often used a morse taper, but a non standard size.
My L00 spindle is MT4.5.

 

[Sergei Slovenija]

With the Long Nose tapers, they often used a morse taper, but a non standard size.
My L00 spindle is MT4.5.

I checked it. The sizes are not the same.

 

[Brad93]

I checked it. The sizes are not the same.

View attachment 383065

What i'm saying is the taper form is based on the Morse Taper.

Perhaps Look for a Jarno taper table.

Either way you're unlikely to find the right taper bush, you'll have to make one or send one out for grinding.

 

[fizzy]

I thought I had MT5, but in fact, it's something else. Lathe chuck of the old American standard, long L1, as far as I remember. The question is, what is the cone? The measurements were carried out on an old worn cone, inherited from a lathe.

View attachment 383061 View attachment 383062 View attachment 383063

The Colchester Triumph has an L1 spindle.
Luckily I have the original bush if you want me to measure it?

 

[Sergei Slovenija]

The Colchester Triumph has an L1 spindle.
Luckily I have the original bush if you want me to measure it?

If the approximate dimensions are similar to my rough sketch, then this is a bingo.

I would appreciate accurate measurements.

They will make me a new one, with hardening and an internal Morse taper 4.

 

[Sergei Slovenija]

What i'm saying is the taper form is based on the Morse Taper.

Perhaps Look for a Jarno taper table.

Either way you're unlikely to find the right taper bush, you'll have to make one or send one out for grinding.

Dimensions of Standard Tapers

This page give the dimensions of Morse, Jacobs, Brown & Sharpe, and Jarno tapers.

littlemachineshop.com

If I have correctly divided inches by giving them to the metric, there is nothing similar.

 

[Agroshield]

An accurate way to measure the taper is to measure the internal one in the spindle. Use two balls (bearing balls), one smaller than the other and measure the depth from some flat part of the spindle nose. A bit of maths and you are there.

See:

Taper Measurement Using Gage Balls

This was the first time I have seen an application for gage balls and I thought it was worth documenting here. I will derive a formula that I saw in the discussion mentioned above for determining t…

www.mathscinotes.com

If the one you show in the photo fits the spindle, dial it in to run true in the four jaw, holding it on the parallel part and then use a clock gauge, a gauge block and a bed stop to work out the change in diameter over a 25mm length.

Blue up the one you have to check the actual fit and measure on the best part. If the surface is rough, place a parallel against it and run the indicator tip on that.

 

[Sergei Slovenija]

An accurate way to measure the taper is to measure the internal one in the spindle. Use two balls (bearing balls), one smaller than the other and measure the depth from some flat part of the spindle nose. A bit of maths and you are there.

See:

Taper Measurement Using Gage Balls

This was the first time I have seen an application for gage balls and I thought it was worth documenting here. I will derive a formula that I saw in the discussion mentioned above for determining t…

www.mathscinotes.com

If the one you show in the photo fits the spindle, dial it in to run true in the four jaw, holding it on the parallel part and then use a clock gauge, a gauge block and a bed stop to work out the change in diameter over a 25mm length.

Blue up the one you have to check the actual fit and measure on the best part. If the surface is rough, place a parallel against it and run the indicator tip on that.

I appreciate it, thanks for the link. So far, as I see it, it is possible to regrind the Morse taper in size MT 5/4. Set on the indicator, the turn angle of the tool post to zero. And machine the finished Morse sleeve from the outside, with a grinding allowance. Borazon ( CBN) plate I found

 

[Brad93]

You'll need a bloody big set of gauge balls for that size taper! Most sets only go to an inch.

 

[Pete.]

Could be Jarno taper if it's got a yank taper on the outside. They are quite close to Morse taper but not the same.

 

[awemawson]

Indicator height (and also grinder / cutter height) is very critical replicating tapers or it can get very confusing !

 

[minimutly]

Indicator height (and also grinder / cutter height) is very critical replicating tapers or it can get very confusing !

Yes, the error effect changes as you travel the length of the taper, unless you are spot on centre all along.

 

[Sergei Slovenija]

Can anyone estimate the angle of the cone based on my measurements? I don't have a program for this nor the skills. Length L is measured along the inclined side, not along the true length, relative to the axis of rotation

 

[Brad93]

Can anyone estimate the angle of the cone based on my measurements? I don't have a program for this nor the skills. Length L is measured along the inclined side, not along the true length, relative to the axis of rotation

If the taper is indeed american, it will be measured in inches per foot rather than angle. the angles are usually very unusual and not whole numbers.

 

[Agroshield]

You'll need a bloody big set of gauge balls for that size taper

That is why I suggested bearing balls. In terms of accuracy per unit cost, they are very economical. Produced in their millions to a tight tolerance, they offer a lot of bang for not much buck.

Just as an example, Simply Bearings sell a 57.94mm diameter one for £14.14 plus VAT. This (https://en.wikipedia.org/wiki/Ball_(bearing)) says the diameter tolerance on Grade 100 is +/- 0.013mm.

The difficulty might be finding ones to suit the dimensions given - if the ones offered by Simply are a representative selection, then nothing they have will work.

 

[Pete.]

Jarno are all 0.600" taper per foot so 0.200" taper over 4"

The figures given in the image below suggest 5.4mm taper over 99mm which works out at 0.2126" over slightly less than 4" which is steeper than Jarno. If you put that taper into a Jarno female it would be over-size at the small end.

 

[Sergei Slovenija]

If the taper is indeed american, it will be measured in inches per foot rather than angle. the angles are usually very unusual and not whole numbers.

 

[Agroshield]

The figures given in the image below suggest 5.4mm taper over 99mm

He has measured the taper in a slightly non-standard way, i.e. the 99mm is along the slope length (see his post #14).

Were it measured conventionally, there are many online calculators:

Taper Calculator

Estimate the taper length and angle using the taper calculator.

www.omnicalculator.com

Taper Angle Calculation | Taper Degree Calculator

Taper Degree is the central angle of the taper measured in degrees. It can be calculated from the taper % or it can be calculated with the number of the different type of tapers.

www.easycalculation.com

 

[Pete.]

The thing to do is set a DTI dead on centre height mounted on the saddle and reading off the spindle taper. Set the dial to zero and move the saddle 40mm. If the dial moves 1mm it's Jarno taper.