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jit's build: upgrading to v2 extruders: vertical adjustment

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This page is intended for Bukobot v1 owners who upgrade their printers to the new v2 extruder and X carriage, and wish to describe how they modified their printer so that the new extruder can reach the platform without causing a collision elsewhere in the machine. One method is described; if you use a different method, please describe it here.

Not all Bukobot v1 printers are the same. Deezmaker improved the design many times between the first and last v1. The particular printer shown on the previous page was one of the early ones, and needed about 7mm of adjustment. Yours might be different, so measure carefully.

Raising the platform

This is probably the easiest method. You don't have to take your frame apart, and you don't have to take out your Z axis threaded rods (which would require you to re-level the X axis).

Read all of the following so you can figure out which parts you need to get before you start taking things apart. The upgrade kit may come with some of them.

It's pretty easy to raise the platform a modest amount. First, figure out how much you need to raise the platform, as described on the previous page.

You need to make a spacer slightly thicker than that. You can compose a spacer out of M3 nuts and washers. M3 nuts are typically about 2.3 to 2.4 mm thick, and M3 washers are typically 1 mm thick. But make sure you measure your spacer stack, because nuts and (especially) washers vary in thickness.

Now look at the long flat head screws that hold the front adjustment wheels. (Here we assume that your bed is currently level.) Measure how much these screws protrude from the bottom of the adjustment wheels. If that distance is less than your spacer height, you might have problems leveling the bed and might need to replace the M3x30mm flat head screws with longer ones. M3 flat head screws are available in lengths up to 40mm.

When you have figured out what parts you need and obtained them, or created workarounds, take your print bed off of the printer. Unscrew the two adjustment wheels from the front of the bed and remove the small flat head screw that holds down the pivot point at the back of the bed. Don't lose these small parts, or those springs.

Lift the bed off the platform and set it aside.

The pivot point is supported by an M3x14mm threaded hex standoff. The upper surface of that standoff needs to be raised by the amount you measured earlier.

(Is that standoff loose? They can get loose, and mess up your prints. If yours is loose, think about applying threadlocker to the screw that holds the standoff on the platform frame when you reassemble.)

Remove the standoff and the M3x6mm button head screw that secures it to the platform frame. Replace that screw with one that is longer by the amount you measured earlier. The length of the screw can be slightly longer or shorter than what you calculate, but if it's too short it won't have a good grip on the bottom of the standoff, and if it's too long it will collide with the flat-head screw that goes down through the top of the standoff. If you can't screw the flat head screw down all the way when you reassemble, you can just cut a little off a screw to make it fit; a cut-off wheel and a tool to drive it would make short work of that.

Put that new screw through the platform frame, from below, and put your spacer on it. Put the standoff back on and tighten that stack. Use threadlocker near the end of the new screw if necessary.

Now put the print bed back on top of the standoff and put the short flathead screw back in (but don't tighten yet).

Put the springs back and screw on the adjustment wheels. Level the bed in the usual way. Don't forget to tighten the screw at the pivot point, but not really tight.

You may find that the springs aren't long enough to hold up the bed at the needed height. You can re-compress them by inserting a spacer above each one, the same length as the first spacer. If the spring is wide enough to slip over your spacer, find a washer wide enough to hold the spring down and incorporate that at the bottom of your spacer stack.

Here, three M3 nuts have been used to raise the standoff by about 7mm. The old button-head screw coming up from under the platform has been replaced with an M3x14mm screw (not visible here). The two M3x30mm flat head screws at the front of the bed have been replaced by M3x40mm screws. On each of those screws is (from top to bottom) a stack of three M3 nuts, an M3 fender washer, and one more nut. The spring fits over the nut, so the last nut doesn't count as part of the spacer.

Other solutions?

jitsbuild-v1-to-v2-verticaladjustment.txt · Last modified: 2013/11/22 14:41 by jit