What about a dove tail joint vertically? Then a pin extending from the face into the dove tail?
Thank you
Could use this track with @Beeâs suggestion:
ILO the dovetail. Not sure of the amount of play though.
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That is pretty sweet stuff. @gero is a bit off grid from what I understand. I believe he can cut a dove tail with what he has.
Thank you
I bought a bag of these,
a bit cheaper, but it looks like they would restrict swivel at the extremes of travel. Instead I bent a pin that avoids the issue.
I think theyâre for the 2x that the four arms attach to.
Dang, I messed up, I redesigned my full sled to use a through bolt and the hardware store is closed for the a few days. I guess Iâll have to leave the shop and spend time with the family. 
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Iâm with ya. I canât build my sled until after Christmas. Tuesday it is.
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Yep, they are intended to go in the middle to attach the arms and spacers to the support in the middle,
I didnât want to require through hole bolting since one bolt would be on the very edge of the sled, and it would require straight holes through the width of a 2x4.
but you can but lag screws in from the top into pilot holes and then other bolts in from the bottom (ideally offset just a bit to be sure that you donât run them into each other)
the reason they are so long is to give you a reasonable amount of shoulder for the arms to ride on rather than having them ride on the thread.
I actually expanded the sled by a few inches to accommodate the hole pattern. Was wondering about that when I looked over the original DXF files of your arm and lined it up with the center.
The dxf file I posted to the community garden is 500mm instead of the 457mm that the stock one is. A big part of that was to get both the holes to land on the sled itself.
the next set of parts I have cut will be just a little different. Iâm trying to tweak things to make the cutting efficient (nicely nested parts that share a cut line) to let me include a metal center piece.
With a metal center piece, I no longer need the 7" long 2x4 and can get away with a much shorter piece. since I have the horizontal arms below the metal center piece, I need to cut away the support to give the arms clearance.
this picture shows a long support, that narrows down to the width of the center part to make lining things up easy (it only needs to go 1/2" or so below the bolt for strength)
top pantograph (1).pdf (369.4 KB)
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Will you have an upgrade kit?
Earlier itâs mentioned that the two long pieces arenât on the same plane. The drawing you just posted looks like they would be now correct? Also, is the 2x necessary if I can source standoffâs similar to those on the sled StephenMcG recently built? Is there a significant force pulling the two central pivots apart?
What about a short wood beam (cleat) that connects he chain and linkage and another cleat on the sled itself.
make it a slight v-config or upside down v to make it more accurate / repeatable to place the sled on the machine in the exact same position
and add a lock system.
Iâll try to make a mock-up if i have time tomorrow
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Remember my sled base is steel so the standoffâs are very rigid! Not that there is much force transferred via them to the sled just the self weight and the cutting/friction forces.
For a quick release I have sourced some 8mm (M6) x12mm Socket Shoulder Screws which have a 8mm body with a 6mm threaded section 12mm from the head, this will allow the extra section of steel which is linear with the chains to be unbolted from the main pantograph arm and refixed without worry over how tight you have to get the nut (with suitable washers).
My thoughts were to use either a standoff or use nuts as a standoff with shouldered bolts to get the right distance to match my CG. I was playing around with using t nuts in the bottom side of the sled so that I wouldnât need to sink them in much. Also, I would like to update to a metal sled using 12.7mm plate at some point. So metal is where Iâd like it to go. Just need to perfect it in wood beforehand so because the metal is far more expensive.
I expect so, the way Iâm nesting things, I get twice as many of the central bars
as I need. Depending on how heavy they end up being, I may just try mailing
them out first class mail
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Earlier it¢s mentioned that the two long pieces aren¢t on the same plane. The
drawing you just posted looks like they would be now correct?
yes, it seems to me that most people were building this way with washers or
similar for spacing anyway (and in the last few kits, I included spacers)
Also, is the 2x
necessary if I can source standoff¢s similar to those on the sled StephenMcG
recently built? Is there a significant force pulling the two central pivots
apart?
It doesnât need tobe 2x, thatâs just the cheapest/easiest thing to do.
what I would do is to use a short chunk of 2x initially, then use the maslow to
cut out multiple layers of plywood (to get the height you need) as a permanent
standoff.
having the horizontal arms under the central support makes the clearance issues
worse, so you need to trim the 2x4 anyway.
I modify the shape of the horizontal arms to give me a bit more clearance, use a
little less material, and make the parts nest better.
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This doesnât need a lot of adjustability, as you only really need to tweak it
when you change fromoen router to another