Cleaning Parts - Not sure of dimensions of the holes

Hi,

I'm hoping someone can help me. I've got the Mendel printed parts and now need to 'clean then' which seems to be mostly using drill bits to open up the holes to the correct sizes.

But I'm unsure exactly what size the different holes should be.
I've see the 'cleaning parts video' so know that I need to be careful not to overlarge the holes.

Where can I get defnition of the size of the printed parts, particularly the holes?
And what software (?) do I need to use to view it?

I've downloded RedSnapper, so can see the .stl files. That's very helpful but doesn't give any dimensions (I think??)

Any help very gratefully recieved

Thanks

Pete

The big holes are 8mm. The rest of the holes in the bot are 4mm and 3mm. You should be able to see which are smaller.

If you have the pulleys I designed then the hole for the shaft is 5mm and the hole for the grub screw 3.5mm.

The holes in Adrian's extruder are all much tighter. They are a mixture of 3mm and 4mm, again you should be able to see which are which. The 3mm ones are the motor screws and one in the base and one in the driven holder which take M3 studding to hold the PEEK support for the PTFE.

I do the three on the filament path 3.5mm to allow for some clearance with oversized filament. I also do the four in the idler holder 4.5mm as it makes it is easer to slide along the long bolts. To insert the nuts in the idler holder I put them on a soldering iron with a conical tip at 200C, heat for a few seconds and then push them in with the iron while holding the bracket upside down.

The counter-bored holes in Adrian's extruder are a pain. I use a 7mm reamer with the end ground flat. I do these now even on my un-reamed sets as it is very easy to go to far with a drill.

Beware that four holes in the carriage lower part are at an angle.

If in doubt of the size look at the assembly instructions and see what size fastener goes through the hole. Although in engineering it is customary to use clearance holes, e.g. 4.2mm for M4, I find 4 mm is sufficient clearance on my parts for a nice snug fit.

Edited 2 time(s). Last edit at 01/09/2011 09:30AM by nophead.

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[www.hydraraptor.blogspot.com]

Nophead,

Thanks for the info. That should get me going nicely

Cheers

Pete

Ok i don't own a reprap but i have an idea you may want to test. since the parts are made out of abs why not dip them in acitone when you're done then leave them to dry? acitone is a solvent for ABS and i'd think that it would get rid of all the loose pieces such as burs fairly easily. might be worth testing on some dud components if you have some lying arround

because of the layered approach reprap takes to building parts, you'll often find they can be absorbant to liquids.

Tf you dipped a reprapped part into acetone, it'd most likely absorb the acetone, then melt from the inside out.

That's a shame. It sounded an interesting idea.

If it 'melts' ABS could there be some scope for smoothing finished printed parts by rubbing on some acetone? I haven't printed any objects yet (long way off) but it seems to me it might be good if there were some nice 'finishing' techniques to apply.

And where do you get acetone from (in terms of popping down my local shops)?

????

Cheers

Pete

Read THIS and THAT.

Look at the Makerbot Soap Dish pictures.

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Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse

... you can receive a really nice finish with a micro torch - some years ago i equipped a hot-air-gun for desoldering with a 0.3mm-nozzle and could remelt all sorts of thermoplastic surfaces with 'hot spots' of maybe 0.5mm diameter ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Hi, im new here and before i start producing some plastic parts for my reprap i would like to be shure in few things. Most of them is similar with this thread.
1. I have downloaded .stl and .sldprt models of standard mendel and prusa version. Because im mechanical engineer, i want produce some part by machining.
2. My next step was making technical drawings from models. And there is what make me "suspective".
Holes for M8 are modelled 8,4mm, M4 4,40mm etc. It is realy BIG "backslash" for me. Is it ok, or should i drill regullar diameter (4mm for M4 etc.) ?
3. even if i accept such a big backslash, when i transform model from small gear of waders extruder, i have found that central hole for NUMA17 steper motor 5mm +0 -17um is designed as 5,5mm! Such dimension cannot ensure funcionality!

What im doing wrong?

You should drill with regular diameter. Circles come out smaller when printed since it's actually printed as a polygon inscribed inside the circle so it's common to increase the diameter of circles to account for this. Nophead has a blog on this. Of course, how much you increase the hole depends on your printer. He proposes to use polygons in the design instead so it doesn't break when printed at higher resolution.