First ever cut and I m not sure what happened, skipped chain link is my suspicion, can someone help diagonse based on picture?
If yes should I add heavier counterweights to the chain, right now they are two small pieces of wood dangling on the side.
Also do i need to recalibrate? Or should i just pick up the chain and place back 1 link on the side it skipped.
Yes, that looks like a chain skip.
the way to avoid chain skip is not with weight, but by looking at the angle of the chain. This type of chain is only designed to tolerate about 3 degrees of angle at the sprocket.
the most common cause of chain skip is that the motors are too far forward or back, look at the machine from the end, are the chains parallel to the workpiece? or are they angled? you want them as close to parallel as you reasonably can. some misalignment will work, but when it gets more than about a 1/2" per foot, it’s likely to cause grief.
This applies to the slack side of the chin as well, which is why having the slack in the center is better than having it hang down from the sides (the long part hanging don from the side, especially if there is too much weigh, pulls the chain close to vertical, which would be 15 degrees to the sprocket (a bit over 3" to the foot), see Weights for chain tension for a picture of the chains in the center with weights.
if you are sure about which side it skipped on, you can probably just move that side one link.
when you calibrated, did you mark a link before extending the chains? you really do want to do that so that you can reset the chains to known lengths and not have to recalibrate.
Thank you so much for your response!!
Makes sense that it is a bad angle that caused link slippage. I will check chain angles today and i am pretty sure it was the right side so I can move it 1 link back there. And great idea to mark for future.
FWIW I found that the assembly instructions for the ring did not work for our setup, they want you to install the ring north of center on the L-brackets, this caused the top of our sled to flop off the work and would not function at all. The sweet spot (again for our specific setup) is in the middle of the L-brackets with the two of the smaller black screws on the bottom portion with the other two on the top. This means zero adjustment but it works for us. Of course with the variations in frames and work thickness YMMV.
what you want to do is to set the router to about the height that it would be
for cutting, and then adjust the ring to be at a height so that if you hang the
sled by the router, it hangs stright. Then adjust the machine so the chains are
parallel to the workpiece (you may be able to add spacers behind the workpiece,
or you may have to change the top beam position.
David Lang
Thanks again, that’s helpful. I wasn’t thinking of adjusting ring height but will try that today.
can you draw this? I’m wondering if that might be another way to try it. I’ve been trying to get the sled to hang at 15 degrees while holding it from the inside of the ring and then adjusting the ring based on the direction it is off.
I try to make it hang straight. the idea between making it hang at 15 degees is
to match the angle of the frame, but you aren’t hanging it in space from the top
when working, you are pulling on it from the sides.
if you have the ring be above the balance point (which is what you need to to to
have it tilt to 15 degrees), then in the top center where you are pulling on
both sides, a portion of your force becomes down force towards the workpiece.
Also, when you are near an edge, pulling above the center point makes it
slightly more likely to tilt off the edge, so you can’t go quite as close to the
edge.
what I did was set the ring high, then dug up a piece of angle iron and clampted
it to a table, then I hung the top bracket of the ring on the angle and moved it
forward and back until it hung straight. I then adjusted the ring to that
height.
this doesn’t need to be perfect (which is why trying t make it hang at 15 degees
isn’t too bad), because the balance changes depending on what height the motor
is at (which can vary depending on the length of the bit for the same depth of
cut).
if it’s way off, then you can pull away from the workpiece at the top center
when the tension on the chains is the highest, or tilt/dig-in/drag more in other
areas.
it’s far more important to have the chains close to paralell than to have the
ring height correct, but if you are going to the trouble of adjusting things, I
advocate doing both at the same time.
David Lang
dlang is correct. If you look at the picture, the shadows of the chains lead me to believe that they are not parallel to the work surface (although this could just be an optical illusion). This may just be a matter of moving your beam towards the work surface in order to obtain the parallelism that is needed. Alternatively, you could also space your work surface out, away from the frame.
When i set my beam depth, i made sure that my sled was sitting on top of flat stock that had a thickness that was midway between the min and max thicknesses of material that i would normally be cutting.
I used a gauge block made from a piece of scrap that had a height that equaled the distance between the work surface and the bottom surface of the chain at the ring. I then used it to make sure that distance was consistent along the length of the chain, up to where the chain extended past the top edge of the work surface.
I also made sure that my sled was at the bottom center of the work surface. This way i had the maximum but equal amount of chains extended in order to check for chain parallelism.
