|Jeff Dayman||16/02/2016 20:05:05|
|1526 forum posts|
In the article Horizontal Shaping Machine in ME 4525 there are some fit issues in the drawings pg 109. The sliding block at left shows a 12 mm width dim which fits in a slot on the main gear which also has a 12 mm dim. This fit will require some clearance/tolerancing not shown in the drawing. On this same block the illustrator as usual uses the bad practice of calling out a thread in a section view across the countersink. This is not OK and can lead to errors. Threads should either be called out with a note and leader on plan view (round hole) of thread, or a note and leader to the thread side representation midway down the thread in the section view.
One other block in the drawings panel at page bottom having 6 dia H7 hole seems to have a feature with an 8mm +.1 +0.05 tolerance. It is not clear whether this block has side rabbet cuts or a centre slot cut. A third projected view would clear this up.
Similarly the centre bottom block with 8 dia H7 hole is not clear whether the cuts are side rabbets or a centre cut slot. Again a third projected view would clear this up.
On the front plate/back plate detail on page 108, there is a note saying "the back plate is identical but without the M4 threads". I think the M4 screws on 30 mm centres in the plate ends will be needed on the front and back plates, since base plate has holes for them both, but the ones on 46.75 centres on the face of the plate may not be needed on the back plate. It would be better to designate the needed/unneeded holes with a "hole X" note with leader line to each, and write "holes X in front plate only"
Drafting 101, sadly gone by the wayside now at schools....JD
15536 forum posts
Lucky that the photo in 4527 shows the blocks so we can see what they look like. Also if they were slots the line would be hidden detail but its solid which would correctly suggest a rebate
I'd say the M4 holes on 46.75mm ctrs are for fixing the dovetail slide so only needed on the front
Edited By JasonB on 16/02/2016 20:44:43
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