View Single Post
  #1   Report Post  
Posted to rec.crafts.metalworking
[email protected] vk3bfa@hotmail.com is offline
external usenet poster
 
Posts: 200
Default Cylindrical grinder setup question.

OK, one for the practical machinists - no, I am not going to buy some
special tool costing zillions to get round this problem...

Turned a MT2 taper on the lathe, 0.5mm oversize. Used the topslide on
the lathe, set it up with a dial indicator for (virtually) zero
deflection along the length of a reference MT2 taper - which, BTW, was
pretty worn/crappy, it was a MT1 to MT2 adapter that had a hard life -
I used a ruler, sighted it lengthwise to get the "best" one for the
setup....

(An aside - the complication is that the school exercise to to grind a
MT3, I changed it to MT2 so it would fit my lathe at home - end result
will be a centre drill holder..)

So, booked the cylindrical grinder, got the tool set for it, the
instructor showed me how to set it, using the aforementioned MT2 taper
I had turned. Took a while, but eventually, using a finger gauge,
measuring the grinding side (important that, as I soon realised) set
it up to AFAIK bloody very close to PERFECT.

Ground the thing, it was out by ?? degrees. Blast, Oh Dear, - and
other appropriate words.

OK, obviously my lathe turned taper was out. Tried to set up the
grinder with the MT2 adapter I had used earlier. Had to move the
tailstock on the grinder as it was longer than my work piece. Set it
up, ignoring the bumps and variations on a worn adapter.

Feeling pretty good about how smart I was , reset the tailstock to the
workpiece. Immediately realised I had lost registration by moving the
tailpiece.

I then ran out of time, will do night class next week to sort it out.

So, good people - how do I set it up to do an MT2 taper? - there is a
degree scale at the end of the grinder bed (where the adjuster is) but
its not accurate enuff to set by, and besides, its an old grinder so
its probably out. By trigonometry - get the degree taper, construct a
triangle, work out offset by this - mm, yes - but how to transfer it
to the end of the bed. Besides it would need very accurate marking out
and measuring, and as there is no gauge on the horizontal travel of
the bed....

There is a dial gauge attached to the adjuster end, but stuffed if I
know how to use it for this setup.

Arrrgh! - help!!!

Andrew VK3BFA.