I'm amazed that so few people give you a like, this is fascinating watching you tackle precision machining. I realise you are busy with the spring planting work, but “I” at least would love to see you re-surfacing a pinch roller. A great vid yet again, thank you.
Thanks Chris. Maybe I should do the silly face with white outline UA-cam thumbnail thing, that might get more "likes" :) I definitely will follow up with a re-surfacing segment. I did show the process on one of the older videos but it's very short and easy to miss (it doesn't take much time). I'll see if I can find it tonight and post a link.
Chris, I found the spot showing the pinch roller grinding, I'm so glad I put it in the description, otherwise it would have been more difficult to locate. Look at: ua-cam.com/video/L1ZD8Fzk6V8/v-deo.html
Hi ABC Custom, I watched this >95% all the way, fantastic job there; loved it! I never knew how knurling was achieved! Relavent to the pinch roller grinding/shaving: it is worth noting that the force/pressure applied to the capstan via the pinch roller will be slightly reduced owing to the small reduction (1% ... 5%?) in the pinch roller's radius. I say this as I did something similar a while back and realised this as I was about to mount the roller back in place! Overall, it should not be a problem, but it is worth bearing this in mind. Some pinch rollers develop a curvature across their height, on some occasions I reversed the roller and all was okay, but I got lucky. ;o) Kind regards Eric.
Thank you Mr. James. I'm curious as to which 5% was skipped? You're correct about the reduction in pressure due to the reduction in diameter. In the 122mk2, the pinch roller pressure parameter is stated as: .838-1.05lbs., I know this because it's written on a sticky note on my bench. My grinding procedure, even with a dimpled pinch roller as in the video at ua-cam.com/video/L1ZD8Fzk6V8/v-deo.html, removes no more than .005" off the diameter of .546", normally less. I have a feeling you could easily calculate the reduction in force given these figures. You may also need the fulcrum centerline, I can provide that also, if needed. Regarding the curvature in height; most of the pinch rollers I've encountered in cassette decks have a convex profile. In reel decks, particularly as tracks become more in number, the pinch roller has a straight profile. I've experimented with flat profiles on cassettes and have found it causes the tape to crawl, a very undesirable effect. That's why I took the trouble of determining the actual profile of a new, factory part, and duplicated it. I don't have experience with every iteration, of course, but the ones I typically deal with, the slight radius appears to be a constant.
@@asbcustom Apologies, I meant to write that the curvature I was refering to was 'off centre', this has happened quite a few times with the old cassette decks I've bought. Thanks for that link, I don't think I've seen that before! I'll keep that link and look at it later today. I'm not sure exactly of the 5% I missed, it was towards the end, I just moved the video time along by a smigen. :)
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I'm amazed that so few people give you a like, this is fascinating watching you tackle precision machining. I realise you are busy with the spring planting work, but “I” at least would love to see you re-surfacing a pinch roller. A great vid yet again, thank you.
Thanks Chris. Maybe I should do the silly face with white outline UA-cam thumbnail thing, that might get more "likes" :)
I definitely will follow up with a re-surfacing segment. I did show the process on one of the older videos but it's very short and easy to miss (it doesn't take much time). I'll see if I can find it tonight and post a link.
Chris, I found the spot showing the pinch roller grinding, I'm so glad I put it in the description, otherwise it would have been more difficult to locate. Look at: ua-cam.com/video/L1ZD8Fzk6V8/v-deo.html
Very nice job on the new nut.
Thanks for sharing the process.
Take care, EM.
Thanks Ed!
Top notch, Peter!👍🔥
Thanks Vadam! How's the tape project going?
Hi ABC Custom,
I watched this >95% all the way, fantastic job there; loved it! I never knew how knurling was achieved!
Relavent to the pinch roller grinding/shaving: it is worth noting that the force/pressure applied to the capstan via the pinch roller will be slightly reduced owing to the small reduction (1% ... 5%?) in the pinch roller's radius. I say this as I did something similar a while back and realised this as I was about to mount the roller back in place! Overall, it should not be a problem, but it is worth bearing this in mind.
Some pinch rollers develop a curvature across their height, on some occasions I reversed the roller and all was okay, but I got lucky. ;o)
Kind regards
Eric.
Thank you Mr. James.
I'm curious as to which 5% was skipped?
You're correct about the reduction in pressure due to the reduction in diameter. In the 122mk2, the pinch roller pressure parameter is stated as: .838-1.05lbs., I know this because it's written on a sticky note on my bench. My grinding procedure, even with a dimpled pinch roller as in the video at ua-cam.com/video/L1ZD8Fzk6V8/v-deo.html, removes no more than .005" off the diameter of .546", normally less. I have a feeling you could easily calculate the reduction in force given these figures. You may also need the fulcrum centerline, I can provide that also, if needed.
Regarding the curvature in height; most of the pinch rollers I've encountered in cassette decks have a convex profile. In reel decks, particularly as tracks become more in number, the pinch roller has a straight profile. I've experimented with flat profiles on cassettes and have found it causes the tape to crawl, a very undesirable effect. That's why I took the trouble of determining the actual profile of a new, factory part, and duplicated it. I don't have experience with every iteration, of course, but the ones I typically deal with, the slight radius appears to be a constant.
@@asbcustom Apologies, I meant to write that the curvature I was refering to was 'off centre', this has happened quite a few times with the old cassette decks I've bought. Thanks for that link, I don't think I've seen that before! I'll keep that link and look at it later today.
I'm not sure exactly of the 5% I missed, it was towards the end, I just moved the video time along by a smigen. :)
wooow, just wooow. im impressed.
Thank you!