02-06-2020, 09:37 PM
(02-06-2020, 12:06 AM)Vinny Wrote: A PLA gear probably won't hold up that well. ABS, on the other hand, should. PLA is somewhat soft and doesn't do well with any heat. The weather is still probably pretty warm there, put that gear on the dash of your car in the sun, you'll see what I mean.
Thanks Vinny. Yeah, definitely not the ideal material. I think I need to get myself around the concepts with PLA first before I venture into the more tricky materials.
Still hot here for sure. We had mid 40's © one day last week (~110F) and I know the car gets around twice as hot. I've measured surface temps in direct sunlight around 85degC (185F) in the past. I won't be printing any custom dashboard parts with PLA !!!
I probably won't end up using that particular gear anyway one, but it was a good test of the whole "idea to item" development - and to see how it came out dimensionally.
Its a fraction too tight to slide onto the shaft on the lathe. Probably just needs a bit of clearance built into the bore dimension for printing, or a quick pass with a suitable reamer.
What I might end up doing is printing a larger gear for temporary use. I'd think the PLA would be fine for a few uses.
I've got a bit of chicken and egg scenario going on - I've previously set up on the mill to cut some real change gears out of mild steel blanks, but got caught out when I went to do the last couple of larger ones, as the arbor I've got doesn't allow the work to clear the head on the mill. I need to make a longer arbor.
There's a bit of work in making one with the special taper to suit the Van Norman mill, so I'd really like to have the larger gears (either 120 or 126 tooth IIRC) to be able to cut an appropriate "standard" thread on the arbor. Yes I could bodge it up somehow with what I've got, but that grates with me...
A PLA gear should do that once off job I think.
Steve