Printing Wade's Block

After many years good service my Mendel90 has got a broken mounting lug (and a cracked idler block). Although the printer still works I have decided to print a complete Wade's Extruder before it does fail.

I have printed the idler block successfully but I am having problems with the Wades block. The instructions that I have say to print it without support on a 1 layer raft. I have printed it with supports, as I tought that I knew better, which has worked but removing the support from the print is very time consuming especially in the idler bearing area. If I print it without supports I am afraid that the filament (Grey ABS 240 Deg C Nozzle and 130 Deg C bed) will sag at the top of the bottom bearing hole and in the idler bearing area. Am I being too fearful about sagging and should I print it just as it says in the "Mendel90_Sturdy_200_200_400.pdf" section 28 although the speed seems very slow?

remember that the center of the bearing holes is drilled out/removed with a 8mm drill from memory. worst of any sag will be in the center and will be drilled away.

To my surprise the Mendel90 Sturdy document section 28 advises to print the parts using a fan which would help with the bridging. I have not used my extruder fan since I started printing in ABS, I have in fact removed the extruder fan assembly, and the Wade's Block needs to be ABS as PLA would melt. I did once do a single perimeter test piece using the fan but the layer adhesion was awful. The parameters in the document state very low print speeds so whether that would aid layer adhesion and good bridging I do not know.

I honestly print all my hotend assemblies in PLA and never had an issue. I'm not sure if I'm just lucky but even a 10-hour print never gave me any issues. I will never print longer prints because it's a DIY printer in a home and I don't like taking the risk of having a failure while I'm not at home or asleep.

As Dust said, the bearing hole doesn't have to be perfect and you need to drill it out anyway for the hobbed bolt if I remember correctly.

My old printer ('Prusa' Air 2, as advertised back in the days) also had ABS parts and almost every part was cracked after five years. I decided to throw it away since it was a terrible model anyway. The parts are being reused in an A0 pen plotter now and I am not planning on using ABS ever again to be honest. None of my PLA parts have cracks in them, not even after 5 years of service.

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http://www.marinusdebeer.nl/

Just to close this out firstly I printed the Wades Block in ABS with support which worked well but it was a pain to remove all of the support material especially in the idler roller cutout. I then printed another one using a bridging speed of 30 mm/s and running the extruder cooling fan 100% only whilst bridging. This also worked out well, in some ways better than the print with supports, and there was very little stringing at the bridges to clean up. I had printed a few bridging test pieces to get the correct settings but I am pleased with the results.