Slope of JMP support

A discussion about the second version of the Jointmaker Pro

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Slope of JMP support

Postby paul@paulkirchnerstudios.com » Mon Dec 12, 2011 10:56 am

Like a good boy scout I built a table with a three inch slope for my new JMP. I'm halfway through with a 5000 cut JMP project, my first with the saw and I was finding I didn't like the three inch slope. I put an inch and half piece of trupan under the back legs and worked with it for a day....liked it. Next day I added another inch and half piece, liked it even more. Some of my cuts I have to watch the wood move through the saw and stop it at a certain point in it's travel. A higher slope to the saw makes me able to watch the cut much better.

I'm not about to remake my table but just wanted to let others know before they commit to something try it out first. Maybe a three inch rise is perfect for you? I guess bottom line is question authority at all times... :D

There's supposed to be a smilie at the end of the above sentence, I'm not seeing one in the preview

Pic of my table with an oh...maybe 75-100lb piece of iron on the base for ballast.
Image
Last edited by paul@paulkirchnerstudios.com on Mon Dec 12, 2011 4:52 pm, edited 1 time in total.
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Re: Slope of JMP support

Postby rwest » Mon Dec 12, 2011 4:24 pm

Paul,

I tried an even higher slope recently:
JMP On The Wall 002.JPG
JMP On The Wall 002.JPG (32.02 KiB) Viewed 8061 times


It wasn't a good idea; the tables don't seem heavy, but even a few strokes makes your arm sore. If I get bored someday, I may try and rig up a counterweight system and give it another shot. It would free up floor space and long boards won't tip off the table either. The whole saw is pretty heavy too, so mounting can't be taken lightly (pun intended.) My house is old so the drywall is only 1/4" over 3/4" T&G boards so I wasn't worried about the saw falling- wouldn't try it without solid mounting.

-Rutager
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Re: Slope of JMP support

Postby paul@paulkirchnerstudios.com » Mon Dec 12, 2011 4:51 pm

Nice!

Floor space I have, wall space is at a premium.
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Re: Slope of JMP support

Postby heidtwd@att.net » Wed Dec 14, 2011 9:40 pm

Rutager,
This is even a little over the top for you.
Bill
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Re: Slope of JMP support

Postby rwest » Thu Dec 15, 2011 6:12 pm

Bill,

I don't do "crazy" just for crazy's sake; I could see some real benefits in space usage and in being able to see the work in progress. I find myself looking over the fence at the cut often and this set-up would give a great view. I've thought about and other have mentioned putting it on the wall so it cuts left to right rather than up and down- someday!

-Rutager
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Re: Slope of JMP support

Postby brandonpeterson789@gmail.com » Thu Jan 12, 2012 2:00 am

To calculate a slope of a line you can use something like:


lda DeltaX
NoChange:
tax
(Plotpixel)
sec (Might not be neccessary if done right...)
txa
sbc DeltaY (Immediate)
bcs NoChange
(Change shit)
adc DeltaX (Immediate)
jmp NoChange

Which gives 11/15 cycles for each calculation/pixel(Oswald do you agree?^^). If unrolling one would have to add a cycle on the sbc/adc by use of ZP instead of Immediate values which means 12/14 cycles (No jmp if unrolled).

This is pretty good. In fact the two things I see as a possible optimalisation here is getting rid of the SEC by use of clever programming and the ADC DeltaX if you scale the relation between DeltaX and DeltaY so that the largest value = 256. You would require a division and mayhaps you get reduced accuracy (not confirmed though). Looking aside from the div. (tables perhaps?!) you'll end up with 9/11 (10/9 if unrolled(need to watch the branching here and build the routine so that you'd get a 9/10 instead) cycles fully optimized. (Am I missing something?)
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Re: Slope of JMP support

Postby paul@paulkirchnerstudios.com » Fri Jan 13, 2012 12:52 pm

brandonpeterson789@gmail.com wrote: (Am I missing something?)



Yes, you are.
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