Metal Top Pantograph kit available

@dlang I did actually. I shouldn’t have posted the first couple of pictures without the router since that is confusing. In the picture that shows the bit poking through the sled the router is mounted to the sled and the sled is upside down. To drill mounting holes in the sled, it won’t matter if the arm is clamped to the bottom of the sled, I just found it easier to do on the bottom.

@dlang I’m updating my post above.

@madgrizzle Did you install the pantograph linkage? If so please share your install notes and results.

I haven’t installed it yet. I have cut the sled and mounted the router, but I haven’t had much of an opportunity to spend more time in the shed.

@madgrizzle
With this kit, the most critical dimension (center arm distance from bit) is in jeopardy of being altered because the distance is measured by putting a side arm on the sled but you can’t mount the linkage directly to the sled, so the mounting location has to “transfered” to a piece of wood that is a few inches above the sled. Since I don’t have a machine shop, this is difficult to do accurately. Since you haven’t tried it yet I understand your perspective. Instructions and help from those that have done it would be helpful.

Are you trying to drill all the way through the block? I see the difficulty you are talking about if you don’t have a drill press. I couldn’t manage to do it when testing out different frame designs unless I used my drill press. You don’t have to go all the way through the wood for this design, but the holes on each side need to be a the same spot. Perhaps using a jig or marks that ensures the wood is perfectly centered along the long axis would allow you to use the holes drilled into the plywood as a guide? Drill one side of the 2x4, flip it, and drill the other side. I’m sure @dlang has some suggestions.

Yes I planned to go through the wood to ensure the holes don’t move. Flipping the 2x4 was my 2nd option that I discussed with David previously but I think it is an invitation for innacuracy even building a jig. Unfortunately I don’t have drill press. I thought my friend had one but I was mistaken. A coworker has one but it would be a few weeks before I could get the block back (ain’t nobody got time for that!). I’ve always wanted one so I’ll probably just end up buying it.

Sweet Brown never spoke truer words. I’ve never used them, but there are relatively inexpensive devices that will “convert” a hand drill into a drill press. But nothing is better than justifying a large purchase based upon a specific need. I bought mine 15 years ago because I needed to drill one hole in one piece of metal… once :slight_smile:

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trying to build a jig that puts the holes exactly in the center of the block
when you flip it is hard. I think that it’s probably easier to try and drill all
the way though

note that you don’t want a 1/4" hole, you want about a 5/32 hole so that the
threads get a good grip into the wood

to drill the hole, my preference would be (in order)

  1. a drill press ($65 from harbor freight, watch for a 20% or 25% discount
    coupon) like
    https://www.harborfreight.com/8-in-5-speed-bench-drill-press-62520.html

  2. a drill guide ($33 from home depot) like
    https://www.homedepot.com/p/General-Tools-Drill-Guide-and-Chuck-36-37/100349264

  3. one person run the drill, a second person watch that the bit is vertical
    (possibly using a couple of right-angle squares as reference)

a completely different approach is to use the maslow to cut multiple layers out
of plywood, add a couple of holes for dowels to make sure they are lined up
(make them a tight fit so you have to pound the dowels in). This may take some
tinkering to get the hole spacing exactly right, and instead of doing the layers
side by side, do one, then move the workpiece and do the next. (The maslow is
very good at doing the same thing again and again, even if the dimensions you
put in the g-code don’t match the dimensions that are cut)

David Lang

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one the block can’t be that long (although you may want it that long to drill it). I designed this to have a block that goes 1/2" above and below the mounting holes (2.5" total), and even with that you will need to notch it slightly at the top to clear the washer for the top mount and one corner at the bottom to let the horizontal arm that is below the center arm to clear when it gets up to 80 degrees from horizontal for the bottom corners.

note that both of the linkage kits have the ability to reference on the bit and
drill through them to make the holes for mounting on the sled. (you aren’t as
likely to damage the metal compared to the wood, but they both have this option)

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I think the ring kit is the only triangulation solution (of the three widely in use) that suffers from that concentricity problem… Both linkage kits use one of the bars to mark/drill the sled. I’m actually not sure how the ring is aligned but it always seemed a little sketch to me.

I would echo @dlang’s hole drilling suggestions above and add one more to the bottom of the list. When trying to drill a hole perpendicular to some material alone and without a drill press I have had great success using a small mirror or even better a CD, place the reflective side up with the hole in the CD where you want to drill, now you can see the reflection of your drill bit in the CD. (you drill through the hole in the CD) Sight down the bit and make the bit and the reflection line up. If they make a straight line then your hole is perpendicular to the CD/surface. I’ve done this a handful of times in a pinch.

In my opinion the bottom line is: a drill press is worth having. I bought mine for $50, it had been laying in the snow and rain on it’s side for 8 years. But it was built in the 50’s so it’s solid and amazing! After restoration I use it almost every single day - no joke.

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This is great. All the time I’ve spent in Home Depot and I’ve never seen one of these before. Earlier this afternoon I splurged on a ~$300 drill press from Home Depot. Will have it in a week or less.

You are correct, I want it that long for now. I was planning to make it about 5.25", the space between the bolts on the center arm, so thanks for that info.

@dlang, @pillageTHENburn and @madgrizzle - I updated my post above. Any feedback on the update is appreciated.

I missed the updates when you posted them. The process you show is exactly what I intended for this kit (you may find it easier to center the small hole with either a 1/8" or 3/32 bit or with a steep v-bit, but what you did is right)

While the result of your rotation test isn’t perfect, it’s far better than what I’ve seen some others post (a 3/4" or wider half circle). If you try it around the top center, the tension on your chains will be higher, so it’s less likely that you will move the entire sled when you intend to just rotate it.

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