PTO repair question

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I have some parts from a PTO to repair - question on the machining tolerance for the seal.It's a standard thin sheet metal type "pound in" seal. I will be cutting a triangle chunk of 6061 3/8" aluminum to put the seal in - how much smaller should the hole be?The reason for the keeper is he lost some pieces and the seal - and does not remember what they looked like.He brought this seal and said "make something that will work." It will go on top of the piece on the left. Yeah that break will get some tig attention The two pieces on the right need to be together. They came with a shouldered bolt that was preened (spiked) to the part that is broken (he lost that though).The shouldered bolt needs a 1/2" section and a 3/8" section.That's all, just hoping someone can let me know how small that hole should be.It's the same cheap looking style seal you would see on a trailer hub.Thanks Last edited by MinnesotaDave; 11-24-2013 at 07:28 PM.Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:I would make the bore the same size as the seal. Is the seal rubber encased or is it just steel? The measurement you are showing seems odd to me, maybe he calipers are a little off. I would think 42 mm or 1.654 inches.
Reply:Are you sure the triangle shaped piece in your pictures is not the seal retainer?
Reply:Originally Posted by leightrepairsI would make the bore the same size as the seal. Is the seal rubber encased or is it just steel? The measurement you are showing seems odd to me, maybe he calipers are a little off. I would think 42 mm or 1.654 inches.
Reply:Originally Posted by leightrepairsAre you sure the triangle shaped piece in your pictures is not the seal retainer?
Reply:Yes same size, if you make it smaller the seal will end up deforming when you install it. It looks like a CR seal if there is a number on it you can look up the size of bore it is made to fit.
Reply:I think I recognize what's being repaired here, and I think there's a misunderstanding about assembly order.I believe those are parts of a Chelsea 100 series PTO, and not to derail MD's project, but what are needed are such common readily available cheap parts, that I can't imagine it's worth the effort to build 'em.As to seal/bore interference? With a smaller seal I'd guess something around .005" or so.Last edited by denrep; 11-24-2013 at 08:18 PM.
Reply:Is there a part number on the seal? If so you could find the nominal outside diameter. The tables on the national and SKF website show it as +/- .001" for up to 3" bore.M&R JohnsonMiller 180SDLincoln weld pak 180Hobart 250ciMill Lathe
Reply:+/- .001" may be some tolerance, but for a snug interference fit, enough to retain a seal, to me, .001" doesn't seem like it'd be enough. Especially not with a bore that's "+" rather than "-".Last edited by denrep; 11-24-2013 at 08:26 PM.
Reply:Originally Posted by denrepI think I recognize what's being repaired here, and I think there's a misunderstanding about assembly order.I believe those are parts of a Chelsea 100 series PTO, and not to derail MD's project, but what are needed are such common readily available cheap parts, that I can't imagine it's worth the effort to build 'em.As to seal/bore interference? With a smaller seal I'd guess something around .005" or so.
Reply:In fact, while tooling is set-up, it'd be most practical and economical to build a few spares, now.
Reply:Originally Posted by denrepIn fact, while tooling is set-up, it'd be most practical and economical to build a few spares, now.
Reply:Here is the unit.Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:Originally Posted by denrep+/- .001" may be some tolerance, but for a snug interference fit, enough to retain a seal, to me, .001" doesn't seem like it'd be enough. Especially not with a bore that's "+" rather than "-".
Reply:Well, I did what was asked and made due with the stuff I was given.I cut a triangle of aluminum and chucked it in the lathe, 0.005" under was the goal (as suggested).The other piece is the broken slider unit that moves the gear. TIG welded the two cracks and to fill the gap.I traced in the outline and rough cut the seal holder to size (no cool tools for that).Using a hex head 1/2" bolt, I turned a button head, shouldered bolt to rejoin the gear engagement pieces.I ground a radius on my cutter so the shouldered area would not have a sharp corner.Where the bolt fits (the backside).The rosette weld.I also cut an aluminum "dust cover" as well (it's as the bottom of the pic connected to the seal holder).After finishing the pieces - the advice that buying the replacements is a better idea was totally correct. Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:Oh, and my 1952 South Bend lathe is awesome!!  Wish I had one years ago Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:You probably made more money making the pieces right? Plus you got more experience and gave the customer what he wanted.
Reply:Originally Posted by leightrepairsYou probably made more money making the pieces right? Plus you got more experience and gave the customer what he wanted.
Reply:Measure the O.D. of the seal and make the bore .003 under that and with a rubber hammer....That is exactly what I would do.And make sure you install it the CORRECT way....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Excellent repair Dave. Now that it's all done and I see the photos of it, I think I have one of those units sitting in the corner of the shop. MM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110Save Second Base!
Reply:Originally Posted by zapsterMeasure the O.D. of the seal and make the bore .003 under that and with a rubber hammer....That is exactly what I would do.And make sure you install it the CORRECT way....zap!