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Throwing my hat in the sled modification ring


#625

The top would be the worst place, as close to the bit as possible is the choice for this approach.
Until I can figure out how to build a parallelogram that would fit around my bulky router or a ‘Ring Kit’ shows up in the shop, the only option for a Third World Country Beta Tester is to prove that this approach is a bad idea.
With the pivot point close to the bit and the centre of gravity moved up, soon we will see how much it will swing at the current speed of the Maslow.


#626

how big is your router? the top pantograph kit gives you about a 4-4.5" radius
clear for the router


#627


I could come up with a Z-Axis mount from down if I change the brick location, or a different weight solution.
Do you see a chance for the top pantograph kit?


#628

yes, if no notch the 2x4 to clear the base, I’d bet that you can get close enough to use my kit.

you would want the bottom pivot on the center to be 3" from the bit, your base is 3.75" radius, the horizontal bars are 3/4" wide, so you need to have .75 + (.75/2)"= 1.1375" (1 1/8") of the 2x4 over the base of your router. I can’t tell for sure from the picture, but it looks like you probably have that.

the Z axis may be in the way a bit, but longer horizontal arms can clear that (I made them 5" hole to hole so they currently move the chains in a 5" radius from the bit)

The basic idea can be scaled out as needed. If the set I have doesn’t fit, I can make a set with custom dimensions for you the next time I get one cut (I have 7 left in this batch, I’ll order more before I run out).

I would suggest that you make a top pantograph set out of wood or cardboard to figure out what dimensions work best for you.

As for the brick mounts, it’s useful to remember that their location is based on the initial X shaped sled, there’s nothing special about them (you just want the bricks to clear the hose). I’m not sure how much the Z axis is really in the way given the handles (the chains get down to ~10 degrees from horizontal, which I’ll bet will mean that we have to clear the handles)


#629

in deciding on the dimensions of a top pantograph kit, you look at:

  1. how long do the horizontal arms need to be to clear the router. the hole-to-hole distance of these arms is the radius out from the bit.

The value of this doesn’t really matter, it’s just that the longer they are the more material it takes, and make sure they are strong enough to not buckle.

  1. how long does the lower section of the vertical arms need to be to let the lower horizontal pivot clear the router.

The smaller this value is the better, because the greater the ratio of the upper section length to the lower section length, the less sensitive it is to slop in the joints. Longer arms just need to be strong enough

I made my kits with 5" horizontal arm spacing, 3" lower vertical spacing and 6" upper vertical spacing. This already puts the wood spacer off the top of the sled (just barely for the stock sled), but this doesn’t hurt anything, the wood spacer doesn’t need to be solid all the way down to the sled.


#630

You can make any of the linkage designs from wood and they work well. The key in making your own is consistency in hole spacing. It doesn’t much matter what the spacing is as long as your router fits inside and they are consistent with each other.
The 45° version I’m shipping has 9" between mounting points, I’m tired and have fuzzy eyes but it looks like that might work with your router. Of course if you make your own you can make that spacing whatever you need it to be!
If you do make your own (any of the designs) I would suggest cutting all the arms then stacking them to drill them. This ensures consistent hole spacing. If you then use the linkage bars to mark the sled things should work out nicely.

I fear I’m stating the obvious here but both the 45° and top-mount linkage designs do the exact same thing with only a few differences that might matter for your setup:
The top mount has more clearance below and to the sides of the router (45° has sufficient clearance for many routers but the mounting points are at 4 points around the router which could get in the way).
The 45° has even force on all corresponding linkage bars, this means that even if there’s slop in joints it will be accounted for in calibration and any error should go away (the top mount version has joints under both compression and tension, any slop in this system moves the bit of the router down and away from the mathematical triangle.)

I have a third possibly viable design that actually solves both weaknesses but I have not had the time to test it yet (it solves those problems at the cost of other complication). Once I do, if it works, I will certainly post about it!


#631

Thanks @dlang and @pillageTHENburn for the moral support. Looks like I would need to take off the handles in both cases. Not only that the power knob is on one of them, its not that easy. There are a few other things in the way. How could I know a year ago, about triangular kinematics. I have no budget to change the router now and kind of got attached to this beast that will do 3 sheets at once with ease. I will keep searching for a ring and for now play with this:
(I have no hat, so I throw a Ghutrah in the ring and a bottle of whisky)
Warning, turn off the volume :slight_smile:
It is clear that there is no bit in the workpiece, that’s why it still looks good.
Still I can cut out the 2x4 to get closer to the bit, plus move the weights to the side and the centre of gravity halfway between the bolt and the bit. It’s going to be interesting finding out how big the drag error will be.


#632

let me know how wide the handles are and I’ll make a kit that will clear them.


#633

how much clearance was there in that setup used in the video between the router and your bolt? how far from the bolt to the bit?


#634

Wow, I really appreciate. The width from the outer parts of the handles is 31cm / is that a foot or a feet?


The clearance to the router case is 2 inch

To the bit from my bolt is an eyeballed 4 inch
toBit
Once you have the total including shiping to Bahrain, let me know and I will settle it. Got excited now :slight_smile:


#635

Ok, it sounds as if we can put a 1/4" bolt 3" from the bit and clear the router
case (although not the foot of the router), is this correct?


#636

Yes, that sound right. With my 6040 cnc running again, I can sink the foot a bit in the sled to gain some z-depth, but not to totally clear it. But cutting out the 2x4 or making layers of aluminium that are shorter at the bottom will work.
Perhaps we should move this to the topic with your kit.

Since my sled looks like a swiss cheese already I’m happy to make a new one if that helps.


#637

you can notch the 2x4 just like you notched the support for your example.


#638

actually, I may just buy a bar of stock and make the new horizontal arms for you manually, since the only critical factor of the horizontal bars is that they must match.

pm me with your address


#639

Could you please tell us what you used to modify the Z on the Bosch (in a separate post perhaps)
I looked at a few bosch machines and the travel on the Z fine adjust knob seemed very limited, did you overcome that ~2cm travel distance somehow?


#642

@walter was struggling with the Bosch router, too. When I looked at it the gear teeth were beveled. Could have missed something but that looked like the only reason for his z position slipping


#643

Don’t think I did not answer Vertex, I did per mail. I also invited Zootalawas to join that mail. I just thought my bulky Bosch was not worth a separate topic as there are plenty of pictures here MaslowCNC/Mechanics/wiki/Bosch-GOF-2000-CE


#644

I was referring to the expected drag error by my “do not do this single mounting point thing” design.

It is to be expected that left and right cuts are above the intended line due the cutter being dragged behind. One side more than the other because of the direction the cutter is turning. Down cuts are expected to be either to the left or to the right of the line. The only direction I can see this work is cutting from down to top. (Or for the guy that wanted to spray buildings with the Maslow. What happened to him?)

Friction was never an issue for me due to the adjustable tilt of my frame. In fact I had a twisting sled when the bit went into the material at 6°because of not enough friction, so went up to 10°. Perhaps it would have also worked if I glued some sandpaper on the sled, just kidding…


#645

Did you have any problems with the Z axis slipping under load?


#646

With the one point mount? I have not cut anything yet with it. Or do you mean with my Bosch. Kindly explain slipping.