craig1410
|
| posted on 22/4/06 at 01:16 PM |
|
|
Drilling propshaft to fit magnet - Okay?
Hi,
I bought one of those Acewell digital dashes which were on the forum a little while ago and I need to fit the magnet and sensor for speed measurement.
The magnet is a nice little chrome plated M6 "bolt" which is designed to fit into a tapped hole.
I have a propshaft made by Autoprop UK and I was wondering if it is advisable to drill a 6mm hole in it for the purpose of fitting this magnet?
Obviously I don't want to compromise the propshaft but given that it is a 3 inch diameter tube of pretty hefty wall thickness (judging by the
weight) I think it would be okay. Anyone disagree?
Also, should I weld on a little piece of steel to act as a balance weight on the other side or is this unnecessary?
Or, should I just use Araldite and maybe bond an M6 nut on the other side as a counter weight?
I'd appreciate any advice you may have.
Thanks,
Craig.
[Edited on 22/4/2006 by craig1410]
|
|
|
|
|
Mark Allanson
|
| posted on 22/4/06 at 01:27 PM |
|
|
I think bonding would be better, a hole may be the start of a stress riser
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
|
|
|
craig1410
|
| posted on 22/4/06 at 01:56 PM |
|
|
Thanks Mark, I'm leaning that way myself. I think I'll cut off the threaded portion from the magnet which will increase the surface area
for bonding and make it a bit more low profile.
Is Araldite the best stuff to use or is there something better? I have some Evostik "Serious Stuff" which I'm going to use for my
cycle wings - would it be okay? I don't know how hard it sets and I wouldn't want something like PU adhesive since it is too rubbery. On
the other hand I don't want something too brittle either.
Cheers,
Craig.
|
|
|
12a RX-7
|
| posted on 22/4/06 at 02:11 PM |
|
|
why not fit it in the flange where it attaches to the diff ? plenty of material to drill into,
|
|
|
andkilde
|
| posted on 22/4/06 at 03:05 PM |
|
|
On the rally car we've used standard clear silicone (industrial stuff) and backed it up with a few winds of fiberglass strand packing tape
(wrapped in the direction that won't unwind it). Magnets are mounted on the rear inner CV.
The adhesive on the tape dries out after a year or so and needs to be replaced but the combination works great, even on gravel.
Cheers, Ted
|
|
|
Tim 45
|
| posted on 22/4/06 at 03:42 PM |
|
|
You MUST make sure that it is rebalnced by attatching a counterweight exactly opposite otherwise it will not be balanced and could cause undesirable
results, sp probably araldite it rather than weld and risk damaging the prop especially if you want to remove the magnet at a later date.
[Edited on 22/4/06 by Tim 45]
|
|
|
Peteff
|
| posted on 22/4/06 at 04:00 PM |
|
|
Cut a slice out of a bike innertube and stretch it over the prop to hold the magnet after you glue it to the prop. If it's near the joint it
shouldn't affect the balance too much.
[Edited on 22/4/06 by Peteff]
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
|
|
|
the_fbi
|
| posted on 22/4/06 at 04:21 PM |
|
|
This may be a totally stupid idea, but I'm sure something along the lines may actually be a good idea.
How about glueing it to a Mikalor hose clamp, on the opposite side to the bolt which does up the clamp.
That way you can "perfect" the solution to be perfectly balanced (off the prop) and you're not actually modifying the prop at all as
you just do up the hose clamp around the prop. Perhaps with a smidge of silicone for it to grip to.
First idea was to replace the bolt in the hose clamp with the magnet one, but that would still need balancing.
I'm sure there is a good idea lurking in there somewhere.....
|
|
|
liam.mccaffrey
|
| posted on 22/4/06 at 04:42 PM |
|
|
i'd do what the fbi said
Build Blog
Build Photo Album
|
|
|
40inches
|
| posted on 22/4/06 at 04:58 PM |
|
|
If the magnet is fitted to a CV joint on a halfshaft, no need to dial in the diff ratio when setting the speedo up and no problem with balance.IMHO
|
|
|
