Jupiter 9 m42 version only close focus on A7

Started 6 months ago | Questions thread
MOD Tom Caldwell Forum Pro • Posts: 43,396
Re: Jupiter 9 m42 version only close focus on A7
1

GnarlydogOZ wrote:

Tom Caldwell wrote:

It could be that someone thought that they could do something similar with an LTM version of the J-9 by simply screwing on a M42 ring - unfortunately it jammed and the winner is going to be the one who manages to free it.

Now that it seems we have established it's a M39, one could also carefully use a Dremel tool with a tiny cut-off wheel and cut the adapter ring, to then easily pry it off. It's most likely just soft aluminum that requires very little effort to cut.

Of course, some careful cutting is required and certainly not the task for the inexperienced Dremel user

Bush mechanic here - works on agricultural machinery:

Sounds like the same trick as used to get the very hard inner ring of a collapsed roller bearing off the spindle it is attached to. Much fun getting these very necessarily tight fit “inners” off otherwise. Locked solid if the bearings were working properly.

Carefully use and angle grinder to cut a groove in the part then use a cold chisel and hammer to snap the ring off. A second groove somewhere else in the radius can be helpful.

Care taken to not cut into the spindle itself.

Now translate to the stuck adapter ring - angle grinders are not advisable ( ). But a partial Dremel cut and resultant groove as Gnarly advised and use a screwdriver in the slot to either finish off the cut by a twist-snap or even as a leverage to try and start the adapter thread so that it could now be screwed off. A fine triangle file might also work and would be slower but less potentially destructive.

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Tom Caldwell

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