Hold down jig

[mikejohn]

I edge ever closer to getting my shopbot!
Now I have a question for which I can't find a previous answer on the forum.
The benchtop is a perfect size for my needs.
I can fit 3 blanks at a time on the table, cutting a vaguely eliptical shape from each.
Can I fit the blanks to a tray,jigged for alignment of the pieces, then simply change trays to a simpler jig aligment on the table?
I see this as the 'fiddly' setting up of the 3 pieces whilst the shopbot is cutting, then a simple release and fix system to change trays.
The sacrifice board would be the bottom of the tray which, as the cut would always be in the same place, wouldn't even need changing.
I will be cutting 15mm (5/8") soft pine.
Is anyone doing anything like this for repetitive work?
Regards
Mike

[gerald_d]

Yes, we do the same with guitar necks. Ten necks per board/tray/pallet that is about 1200mm (4') square. Our "pallet" is 20mm MDF.

[mikejohn]

Hi! Gerald
Pleased to hear from you.Missed your input in recent days.
Do you find you have developed techniques and jigs over the time you've been running the shopbot to maximise the running time of the machine?
I haven't seen a lot of chat directed in this area.
Thanks as always
Mike
P.S. Any idea of the % price rise 14th November?
I was planning my purchase for December!!

[fleinbach]

Mike

I heard the increase would be approximatly 10%.

[mikejohn]

Thanks Frank,
Luckily the close election is forcing the dollar down against the pound, so maybe a little of the rise will be offset.
Your exporters will be pleased!
If, as an earlier thread suggested, the price hike is just to cover the increased cost of steel, there must be as much steel in a shopbot as a sherman tank!

Mike

[jim_ludi]

Gerald - Could you post a picture of your pallet setup (A picture’s worth…)? The concept seems like it would be very useful for small/medium part, mass production. Are you using vacuum hold down for the parts, and do you have to machine both sides of your parts? If so, how do you accommodate that process within the pallet concept. I assume that you use the Bot for more than one purpose, so how are you re-indexing the pallet and zeroing the X&Y axis to it after you've disturbed the setup. Jim

[gerald_d]

Jim, I wont be back at the workshop until next year, we have already shut down for our summer break.

The "pallet" is simply like a mini-table top. A sheet of 20mm MDF with dowels protruding out the top. Plus bolt holes where we bolt the parts to the board using something like a counter-sunk head bolt from the bottom.

Actually the bolt heads are tack-welded to about 30mm square plates that fit into a square recess cut by the SB - this stops the bolts from turning while tightening the buts. Accurate bolt holes and bolts sometimes serve the purpose of location dowels. The blank parts have dowel/location holes right through, and they get reversed using those holes as references.

Indexing the pallet to the cutter is easier than trying to zero the cutter to the pallet....
We clamp strips of scrap to the table, one along y-axis and one along x-axis. Then we cut reference edges on those strips, and then push the pallets against those edges.
This zeroing method is used for most jobs, not only for pallets.

[mikejohn]

Gerald
We do not, in any shape or form, envy your well earned and deserved rest on the white sandy beaches of South Africa, whilst we huddle around the stove, with sleet, snow, frost and fog creeping under the door.
It is not, in my opinion, in any way cruel or unkind of you to tell us of your holiday plans.
And I am still willing to wish you and yours, and all shopbotters,

4778 and a prosperous New Year.