ISO 286 Limts & Fits
ISO 286 Limts & Fits
(OP)
I have a design guide for wear rings which uses the ISO standard limits & fits for the bore dia and groove diameter. I don't have this spec and wonder what would be the tolerances on a couple of dimentions.
First one is the bore diameter. It would be 16.501 H9. (In actuality the T-Seal would govern this dimension) The groove diameter would be 16.501 dia - .250 h8. This is the more important tolerance.
Could someone tell me what the tolerance would be for these two dimensions? Or, if possible, a web site that lists these limits and fits.
Thank you.
Eyke
First one is the bore diameter. It would be 16.501 H9. (In actuality the T-Seal would govern this dimension) The groove diameter would be 16.501 dia - .250 h8. This is the more important tolerance.
Could someone tell me what the tolerance would be for these two dimensions? Or, if possible, a web site that lists these limits and fits.
Thank you.
Eyke





RE: ISO 286 Limts & Fits
16.501 H9 = 16.501 +0.043/-0.0
16.501 h8 = 16.501 +0.0/-0.027
I do not understand "16.501 dia - .250 h8".
ISO fits charts are in any ball bearing company catalog - at least good selection of fits used in bearings;
Also in Machinery's Handbook. Try to understand how they work, it is an excellent design tool. We had in this forum discussion about it before.
gearguru
RE: ISO 286 Limts & Fits
1. If it is 0.25 deep, then your nominal dia will be
16.501-2*0.25 h8 = 16.001 h8 = 16.001 +0/-0.027
2. If it is 0.125 deep then 16.501 - 0.25 = 16.251
And 16.251 h8 = 16.251 +0/-0.027
Note: the tolerances for dimensions over 10.0 to 18.0 included, are the same. ISO tolerances are always assigned to a "groop" of sizes.
Look on Thread404-14730 in this forum.
gearguru
RE: ISO 286 Limts & Fits
I did look in the Machinery's Handbook (25th Ed), but did not see h8 for the shaft tolerance, unless I'm not reading this right. I did have a look at the thread you mentioned. I'll have to read it again to fully grasp what you were saying.
AFA the 16.501 dia - .250 h8, the groove dia is .250" less than the bore dia. The slot would be .250 less 1/2 the diametrical clearance deep. This is for piston wear rings.
Are your numbers in metric or English? .043 seems like a lot of tolerance for a wear ring. I ran the conversion and it comes to .0017, which sounds a little closer to what I'd expect.
The tolerance of the bore dia for the t-seal is +.004/-.000.
Thanks for the info, now if I can find that Timkin bearing catalog....
Cheers!
Eyke
RE: ISO 286 Limts & Fits
Guess that should answer the question.
Thanks for you help.
RE: ISO 286 Limts & Fits
When working with ISO fits, be sure that your dimensions are in mm.
gearguru
RE: ISO 286 Limts & Fits
Prboz
RE: ISO 286 Limts & Fits
Try to search using Google, Yahoo etc.
There are some pages with selected ISO fit charts on the Net.
I lately found this page:
http://www.tecnologix.com/en/tools/fset_.html
You can find there a nice calculator for the fit, actual min/max dimensions (if you know the nominal and tolerance symbol) and clearance/interference.
gearguru