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View Full Version : ISO 20 taper dimensions for my ATC



imitheo
04-01-2018, 09:27 PM
Hi, the title pretty much says it all. I didn't had any sucess searching the web for this information, i designed my ATC using a CAD from a friend of mine that he said it had the dimensions correct.

But i decided to investigate a little and see if i wasn't making any mistakes.

Then i found this website:

Techniks ISO20, ISO30, ISO40, and SK30 Collet Chucks (http://www.techniksusa.com/wood/isosk.htm)

It has some CAD files and i downloaded one to check the dimensions were equal to my random ISO20 tool holder CAD file.
I checked the angle first, on my CAD file it reads 16° on the TECHNIKSUSA CAD file it measures 17°.

Can anyone point me to the matching pullstud and correct iso 20 taper dimensions ?

imitheo
04-02-2018, 11:02 AM
bump

ger21
04-02-2018, 11:27 AM
I think it's 7/24, which is 16.26°

imitheo
04-02-2018, 03:23 PM
Isn't there a book or some standard that states this ? So i can use as reference ?

ger21
04-02-2018, 03:41 PM
https://en.wikipedia.org/wiki/Machine_taper

imitheo
04-02-2018, 05:30 PM
Which one of these is ISO 20 ?

vmax549
04-02-2018, 07:13 PM
8deg 17'50" ISO20 taper

(;-) TP

imitheo
04-02-2018, 08:55 PM
Right, any standard or documentation supporting this, please ?

ger21
04-02-2018, 09:16 PM
Everything I've found says the taper is 3.5" per foot, or 7/24.
Look at the NMTB on the Wikipedia link. But I think they specify the angle wrong.

ger21
04-02-2018, 09:27 PM
I checked the angle first, on my CAD file it reads 16° on the TECHNIKSUSA CAD file it measures 17°.

If I look at the Techniks CAD file, it's actually 16.5944°. This is also what the Wikipedia page says.

I'm not sure where this comes from though, as 7/24 is 16.29°???

imitheo
04-02-2018, 09:56 PM
I see, i didnt know that NMTB, going to read right now. Thanks ger21.

The pullstud for those models are standard too ?

vmax549
04-02-2018, 10:08 PM
Technics drawing # L06000-2516 ISO20 collet holder. The included angle of teh cone is 16.261112 deg BY their dimensions

(;-) TP

mactec54
04-02-2018, 10:48 PM
Technics drawing # L06000-2516 ISO20 collet holder. The included angle of teh cone is 16.261112 deg BY their dimensions

(;-) TP

If that is what is on there drawing it would be incorrect the correct included angle is 16.5943 which is 7/24 or 3.5" per foot

It is easy to draw it in cad

imitheo
04-03-2018, 12:56 AM
Is the retention knob for ISO 20 tool holder a standard part ? I CANT FIND ONE with dimensions.

ger21
04-03-2018, 07:19 AM
If that is what is on there drawing it would be incorrect the correct included angle is 16.5943 which is 7/24 or 3.5" per foot

It is easy to draw it in cad

How do you draw that and get 16.5943???

My drawing gives me 16.26, as does the arctan of 7/24.

ger21
04-03-2018, 07:25 AM
I've never used an ISO20 spindle, but used to use an ISO30, and there were many different types of retention knobs, specific to different spindles.

mactec54
04-03-2018, 08:23 AM
How do you draw that and get 16.5943???

My drawing gives me 16.26, as does the arctan of 7/24.

Your cad may have some tolerance settings, that need to be set for a lower tolerance than what you have I always use .0001, but can go lower than this, as you can see by the drawing it is not low enough, as it is missing the 4th digit after the point, if you can't go that low then you would have trouble drawing something like this to get it as accurate as it needs to be, this is 7/24 or 3.5" per foot

ger21
04-03-2018, 08:40 AM
OK, I thought it was a right triangle with the base 24 and the height 7. Now I see how it's done. Thanks.

genixia
04-07-2018, 04:19 AM
All the ISO collet chuck toolholders are specified at 8deg 17' 50" as noted before by vmax. ISO30-50 appear to have been superseded by the DIN standard DIN69871 that includes through spindle cooling. ISO toolholders are specified in ISO297 and deriviatives, if you have access or want to buy the standard. It's useful to remember that these standards are uncommon in the USA (where other NMTB standards using the same taper such as BT/CAT prevail), and that you need to look to Europe to find them, especially in the smaller sizes. Schaublin (Switzerland) sold the ISO10 toolholders that were used in the (US built) Light Machines Benchman XT. I read somewhere that they cost in the region of $600 each, but they were balanced to 45k RPM. Anyway, Schaublin are the only vendor I've found that has enough detail in their online catalog to demonstrate that they know this standard inside out. They make drawbar collets, grinding gauges and test arbors in addition to toolholders and balanced nuts. It wouldn't surprise me if they were the originator of the standard. The retention knob is standardized too, although at least one vendor went way off-standard and created a different retention knob for the ISO20 size. It's all in the catalog linked below, and should be trivial to verify. Maritool (USA) have made balanced ISO20 toolholders before (referenced in a recent NYCCNC tour video), so they might be useful to talk too about retention knobs.

http://www.makparsan.com/images/catalogFiles/RBC-Schaublin-collets-2012-07.pdf ISO20 starts on page 150.

mactec54
04-07-2018, 10:18 AM
All the ISO collet chuck toolholders are specified at 8deg 17' 50" as noted before by vmax. ISO30-50 appear to have been superseded by the DIN standard DIN69871 that includes through spindle cooling. ISO toolholders are specified in ISO297 and deriviatives, if you have access or want to buy the standard. It's useful to remember that these standards are uncommon in the USA (where other NMTB standards using the same taper such as BT/CAT prevail), and that you need to look to Europe to find them, especially in the smaller sizes. Schaublin (Switzerland) sold the ISO10 toolholders that were used in the (US built) Light Machines Benchman XT. I read somewhere that they cost in the region of $600 each, but they were balanced to 45k RPM. Anyway, Schaublin are the only vendor I've found that has enough detail in their online catalog to demonstrate that they know this standard inside out. They make drawbar collets, grinding gauges and test arbors in addition to toolholders and balanced nuts. It wouldn't surprise me if they were the originator of the standard. The retention knob is standardized too, although at least one vendor went way off-standard and created a different retention knob for the ISO20 size. It's all in the catalog linked below, and should be trivial to verify. Maritool (USA) have made balanced ISO20 toolholders before (referenced in a recent NYCCNC tour video), so they might be useful to talk too about retention knobs.

http://www.makparsan.com/images/catalogFiles/RBC-Schaublin-collets-2012-07.pdf ISO20 starts on page 150.

That is a good company and have always made quality tooling


If you go through the PDF file you posted the Taper is the same BT40 Cat40 NMTB all use the 8 deg 17' 50" taper, the only tooling that is really different as far as taper goes is HSK

imitheo
04-08-2018, 02:59 PM
Thanks for the awesome documentation!