Chain Configuration

[ukdel]

I apologise if this is being bought up yet again, but I am having real difficulties in getting to the final set up and chain configuration. I “aquired” through a freind the MakerMade Jumpstart Maslow CNC Kit and am installing it for use in my local MakerSpace. As such it doesnt come with a Z axis, which we plan to make as per some of the suggestions on here and the wider web. The frame is all made, which gives a working area of 1200mm (4ft) high and 1800 (6ft) wide . I kept the upper beam as long as I could and it is about ~3000mm (~10ft), and kept the normal length of chain. I got all things “working” and was using Makerverse to calibrate. In setting the chains and paracord tensioning I followed the instructions , and this is where I came unstuck. It is clear that the skinny paracord doesnt put a great deal of tension on the chain and to be honest it didnt just look right. this machine didnt have the the “spring” tensioner which seem to come out when the M2 started to go through a bit of redesign. Looking on this forum and other Web searches there seems to be a plethora of great ideas which are really difficult to understand what the latest thinking and “best” method of chain tension… Please please can someone let me know in its simplest form what the latest thoughts on this are (considering my machine was the first of the “M2”) and this tricky subject. Would love to get this working for the MakerSpace,.

[dlang]

it should be elastic, not paracord (although similar in size), some people
double it up.

I prefer to use weights and instead of the small sprockets and hooks that can
get lost, I use 3" clothsline pulleys and run it through pieces of plastic
conduit

Weights for chain tension

I was having problems with the elastic cord not keeping enough tension on the slack and the chains twisting as a result, I made a quick trip to home depot and got the cloathsline pullys and a couple conduit sweeps, here is the result (works much better, but I need to relocate the end of the chain to handle the full work area) I didn’t bother relocating the metal pulleys from the old arrangement. the screw in the center is to hold the sled out of the way. the paracord seems to have no trouble w…

David Lang

[ukdel]

Sorry David… yes it is elastic cord and not paracord, and as you stated it doesnt keep the tension on. I thought I would use a bungee cord in place of the single spring in the “later” models and it worked a bit better. Your idea of using weights is a good one as it give a constant tension on the chain pulley so I might try that. Thanks for the response. Derek