turning RFQ

[millman52]

Mild steel,
Need 1 part

[txcncman]

+/-.0005 on the ID. What are you using this for? -.00/+.005 on a radius for rope? That is crazy. If I were to even attempt such non-sense...nevermind. Just walk away...just walk away...

[Dualkit]

As the previous poster mentioned, open up the tolerances. I have made quite a few pulleys (none this big), and can honestly tell you V-belts are very forgiving. First the belt should ride nowhere near as low as the bottom of the groove radius if sized properly. I made v-belt pulleys for small block dirt track cars that had engines that spun 8,000 rpms and you would never notice .005 t.i.r. on a pulley. Open up the bore to +/-.0025, and just put a minimum on that radius for strength.

[millman52]

The ID is for a press fit for a caged needle bearing. & the tolerance can be opened up a bit but not much more in the neighborhood of 3.625 minimum to +.0015 The "V" groove is not for a V belt, but is for 1/2" wire rope. The depth & width of the V is to allow the wire rope to spool across the width of a 36" long cable spool & still self align to the center of the groove.

The ID size will be finalized once I have the actual bearing in hand (1-2 days) to measure.

[miljnor]

also where is there a T.I.R. call out? These aren't tough tolerances for a machine shop but the pulley is big.

but the tolerance for everything but the bearing are a bit overkill regardless of what type of rope it is. lol

good luck on this for anything reasonable.

And I would look the bearing spec up its probably more like +000 -.0005

[millman52]

miljnor, I am sure the tolerances & TIR on everything except the bearing bore can pretty much be barnyard tolerances so long as the bearing bore is pretty straight with the rope radius in the bottom of the groove.

I didn't create the drawing and I haven't seen the old part. I would imagine, but am guessing the entire original part was a forging/casting possibly including the radius of the rope groove. The only real machining being done on the center bore. & width of the center hub.

Anyone wishing to bid on the part please state the tolerance & TIR you can comfortably hold & I will ask for approval before any actual work is done.

[miljnor]

T.I.R. Stands for Total indicated run-out. Was actually wondering where that was in the drawing. Maybe my eyes are getting too bad to see it. Usually signified by a cross-hair with a circle around it and an elaborate box with letters in it.

maybe time for some new glasses.