Ian Parkin | 15/09/2020 18:22:14 |
![]() 1174 forum posts 303 photos | I need to fit a tachometer on a machine in the morning how do i fit the small button magnet to a shaft? if i glue it to a mild steel shaft does the steel sap the magnetism ? |
JasonB | 15/09/2020 18:26:01 |
![]() 25215 forum posts 3105 photos 1 articles | Araldite worked OK on mine |
Steviegtr | 15/09/2020 22:41:16 |
![]() 2668 forum posts 352 photos | Posted by Ian Parkin on 15/09/2020 18:22:14:
I need to fit a tachometer on a machine in the morning how do i fit the small button magnet to a shaft? if i glue it to a mild steel shaft does the steel sap the magnetism ? No it will be fine. Steve. |
Brian Sweeting | 16/09/2020 00:10:24 |
453 forum posts 1 photos | Make sure that you stick the magnet the right way around, you just know that it will happen. |
Neil Wyatt | 16/09/2020 15:57:27 |
![]() 19226 forum posts 749 photos 86 articles | I found the small neodymium magnets are so strong that popping one in a keyway or spanner notch has always worked for me without adhesive. Neil |
Enough! | 17/09/2020 01:29:22 |
1719 forum posts 1 photos | ... which probably makes Brian's admonition even more important |
Ron Laden | 17/09/2020 06:59:34 |
![]() 2320 forum posts 452 photos | I have fitted one to my mill and one to the lathe ( dry with no adhesive) and neither have budged yet. Edited By Ron Laden on 17/09/2020 07:07:17 |
SillyOldDuffer | 17/09/2020 10:22:15 |
10668 forum posts 2415 photos | My lathe's magnet sits in a slight recess, which I guess gives it more grip on a machined flat surface and stops it sliding on a smooth round shaft. Sliding may be a problem - although I can't imagine a strong magnet coming off, it might move sideways. Sideways movement may not show up in practice. Provided the magnet's close enough right-left to activate the hall sensor, rpm will still be measured. Even if a magnet gradually walks around the circumference, the effect on rpm readings will be small. A spot of glue would also stop sideways movement and be less trouble to apply at home Another guess; it's cheaper for the manufacturer to machine a flat recess on a lathe spindle than it is to clean it carefully and apply a glue resistant to oil and heat. Also easier to fix an unglued magnet if untrained labour puts it on upside down. Dave
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Ian Parkin | 17/09/2020 16:30:57 |
![]() 1174 forum posts 303 photos | I did the job today just ground a flat on a 20mm silver steel shaft and placed the magnet and it stays there even at 1000rpm its been running an hour or so now I had it in my head that a magnet would have need putting in a non ferrous collar to work adequately thanks for all the help with this |
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