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Sprocket missed a link... chain fell

Hi guys! 17 y/o here, I have some experience working with the Maslow. Recently I added 1ft of an extension to each side. Somehow today… a chain link stuck up causing the following chain to not drop down, thus causing the chain to ball up on itself. When that happened there was basically space between the chain and the sprocket and it fell because there was no chain for the sprocket to grab on to. (Sorry I can’t do a better job explaining or if that explanation doesn’t make much sense -it all happened really fast)

I think that it could have been the chain angle between the sled and the sprocket, and how this angle is slightly outward. (When it gets to the extreme ends the chain makes a click sound as the sprocket tries to grab it)

I’ll include photos below of the damage as well as where it slipped… I’ll try to get video of it in action soon if that is needed.

If anyone can give any advice or input on how to change my setup that would be amazing! I am also aware that my wording may be ambiguous… so I’d be more than happy to answer any questions/clarify any details!

Edit: The problem was with the left motor, I have used this setup before… it still clicked a little bit it was not that bad. Since last time I cut off an additional 10in of chain making it tighter. I did this because when I got the extension I also needed to buy extra chain. The chain length on each side is Default chain length + 2’8”. My beam is 12ft long but I only work within the default 4x8 workspace.

yes, the chain angle probably caused this.

First, check that the ring height on the sled is correct (with the router near
the normal cutting position, if you hang it by the chains, it should hang with
the sled perpendicular to the ground)

Second, you will want to adjust the top bar position to make it so that the
chains are parallel to the workpiece.

Assuming your ring is at the correct height, you would move your top beam out
from the frame.

David Lang

Hi,
Thank you for the fast reply! I think my ring height is good, as I have not had a problem with it ever in the past (even before the extension) When you talked about the top beam… did you mean raise the top beam as in build it higher up?

Thank you for the fast reply! I think my ring height is good, as I have not
had a problem with it ever in the past (even before the extension) When you
talked about the top beam… did you mean raise the top beam as in build it
higher up?

not further from the ground, further forward from the frame, you want the chains
to be parallel to the workpiece (or very close to it)

IIRC, roller chain is only supposed to be able to work at an angle of 3 degrees
(i.e. not much)

David Lang

I’m curious about the finger joints in this piece shown, as I’ve been trying to figure out how to lay them out. Did you design this yourself, or is there a program or template to help draw them?

No, sadly I did not design these myself… However, fusion 360 would probably be good to draw finger joints. I haven’t used it a whole lot but of those times that I did use it it was pretty simple and intuitive to draw curves.

Thank you very much! Come to think of it I added an extra scrapboard which brought the workspace out an extra .5 or .25in + the 5mm underlayment that I’m cutting. That said, do you think that removing the middle scrapboard could be an alternative?

(Or adding more)

whatever it takes to make the chains parallel

So to make sure I understand you extended the motors out by a foot on each side by use of steel angle?
Does the right chain in the first picture come off the top of the motor, go under the idle sprocket, loop over and come back under the chain, crossing itself? (Your left side does not appear to do this)Then the bungee goes around the bearing, loops around and back under the chain near the S hook?
The clicking is indicative of the chain being misaligned with the sprocket. Mine did that too. Where my chain comes off the top of the motor, and heads to the sled is out at an angle too. But the weight of the sled seems to prevent skipping from that side (when retracting). My issue was the slack side (when feeding out). I use light counter weights, and in my instance had to add a passive guide to keep the slack side inline with the motor sprocket. Make sure the slack side operates smoothly with no binding. If you hold the chain near where the motor sprocket would be(I temporarily added a pulley under the motor for testing the chain retraction), pull the chain out and let your bungee cord retract it in to make sure your chain is inline and is smooth through the whole range. Pay attention the S hooks aren’t catching, or replace them with oval shaped things from the hardware store.

Edit: also be aware of any stiff links. When mine would retract, the stiff link would come back over the top, and stay bent, when it fed out again and approached the motor sprocket there was the possibility of a skip. If in feeding out the chain it stuck to the underside of the sprocket (when you feed out chain without the sled attached, this is a good possibility of balling up) that would mean the chain is not parallel to the workpiece on the non-slack side. You want the chain link to enter the slack side and exit to the sled centered in the link, not hitting the inside edges of the chain to tight, this is where you get the clicking.

Thank you very much! It’s interesting that you mentioned the stiff link as I thought that that could’ve been a possibility as well. I applied chain degreaser to prevent dirt/gunk from sticking to the chain. Any ideas on how to get the chain links to move as freely as possible? (Like any cleaning method)

As a long time bike owner, here’s my preferred chain maintenance.

  1. Put the chains into a tub of water mixed with dish soap and or degreaser. Scrub off all the old grease and sawdust. Rinse.
  2. Pull the chains out of the water and give them a soaking spray down of WD-40. (You’re using it as a drying agent, not a lube.) Dry them thoroughly with paper towels or shop towels.
  3. Once they’re dry, lubricate them with a ‘dry’ style chain lubricant. One drop per link. White Lightning Clean Ride is my preferred brand. You want something that will leave the chains lubricated and protected but not sticky.

Going forward, it should be much easier to keep your chains clean. I usually just give them a swipe with a dry shop towel followed by a swipe with the towel barely dampened with solvent.

My chains arrived with a protective film of grease on them that was a magnet for sawdust. They’d get gunked up with sawdust and I’d start jumping links like crazy. Once I switched to a dry lube, it’s been much better.

I think that I only have spray degreaser… do you think that that could be sprayed in the water?

Dish soap and hot water works. Pouring spray degreaser into water will probably dilute it too much. The idea is to soak and scrub all of the grease, grit and sawdust out of the chain and then replace it with a non-sticky lubricant.

Got it… thank you for the advice! I’ll let you know how it turns out!

Did you ever try the hot wax religion with your bike chains? Side curiosity…

I am using a 12’ bar. My top bar is 32” above the top of the work surface with the Bolt Together Frame. I was having two significant clicking issues related to the out feed of the chain (I go over the sprocket to the sled).

One of my issues was a bad pulley. That was simple. The second was similar to your issue. Particularly like the photo where the chain rides onto the top beam when toward the outside edges of the work surface.

I noticed that the chains were not parallel to the work surface. As a result I removed one of the spacers between the top rail and the vertical support. The frame plans called for two 2x4 and one 3/4” spacers. I removed the 3/4 spacer and it brought the chains almost into parallel with the work surface. Because of the difficulty removing the spacers I haven’t swapped out a 2x4 spacer with the 3/4” spacer. When I do that I believe I’ll be parallel to the surface.

Just removing the 3/4” spacer helped a lot. This may also help, particularly if using the Bolt Together Frame.

I haven’t. I bounce back and forth between “It sounds really cool and I want to try it” and "My chain is doing fine and I don’t want to go through all the trouble. "

Oh. Soaking clean chain in hot wax works beautifully to dry seal it provided it is really deeply clean before the soak and you never get oil on it or sprockets. If there is any grit anywhere at the beginning, the wax will encapsulate it and help transport the grit around the system making things worse. Oil makes the wax sticky exacerbating the problem. Also does not work well for some modern O ring chain. Most waxes are petroleum based and some contain silicone. Both can deteriorate some O ring chemistry. Do you know the composition of your wax or chain O rings?
It would be interesting to test with maslow. Being dry, sawdust might not stick. But energetic sawdust might embed itself in the wax.
FWIW I really like to use a spray on wax product called Boeshield from Boeing on all my aluminum tool soleplates, tables, T slots, and adjustment slots. It prevents sticktion and galling very well. Too much overspray to be practical for chains.

Thank you very much! I figured that the problem had something to do with the default frame not being optimized for what i’m doing now. That said, I am going to design a new frame… Would you be able to send a picture of your setup? I think that it could be useful to me as you have the 12’ bar which I have as well. Thanks!