Makign holes for M4 Heat Set Inserts  

RE: Makign holes for M4 Heat Set Inserts

This discourse sure has gone South fast. Anywho, you can look at Prusa's e-shop for heat threaded inserts

 by CNCKITCHEN. The e-shop has both  Metric long and short sets and the packaging includes diagrams for making holes. Also look at CNCKITCHEN's printables in that he has a downable negative space profiles for use in CAD and Slicers. I have use CNCKITCHEN's inserts and RUTHEX inserts and they work will. RUTHEX sells both Metric and Imperial if you might need such. Recommend you get the soldering tips for threaded inserts, it will save you a lot of grief. AS to press I have built and used the Adafruit press and the stealth press by Iconic Fab both are useable; Adafruit's is quite a bit of sloppy IMHO but useable, the stealth press is nice like the key chain return -- nice smooth movement. One can find a lot of press designs on printables. You can find other  sources of heat inserts, they may or may not work well. CNCKITCHEN and RUTHEX have worked well for me. PS I have nothing to do with either supplier just a user. 

Hope that is some help

St George 

RE: Makign holes for M4 Heat Set Inserts

This discourse sure has gone South fast.

I was rather disappointed that it didn't stop when I tried to say that's not how I think. I found it frustrating that wasn't enough.

The e-shop has both  Metric long and short sets and the packaging includes diagrams for making holes.

The thing I like is that I know ordering something from Prusa means it's good quality. But, on the other hand, I haven't ordered from Prusa since I got my original printer and a few other parts with it. My concern is shipping time/expense for delivery on this side (in the US) of the Atlantic. I did try to find a Prusa shop in Amazon, hoping maybe they have something set up there so it makes shipping easier in the US. Or is there another solution and I just haven't seen it? As I remember, aside from the expected delay in my printer at the time (If I recall, there was a backlog?), that the cost and timing for shipping to the US was significant. If I'm wrong and that's not always the case, that'd be nice.

I have use CNCKITCHEN's inserts and RUTHEX inserts and they work will.

Thank you for recommending them. I'll be looking into both names.

Recommend you get the soldering tips for threaded inserts, it will save you a lot of grief.

Right now I have some cheapie inserts. Often I start with cheap on things like this for testing and learning, then go to the good stuff. In this case, though, going with cheap meant I didn't get good data on the insert sizes with the inserts. I did get a soldering iron tip, but you're right and I was figuring that once I had tested and experimented, I'd have to move up in terms of insert quality and a set of soldering iron tips for the various sizes.

AS to press I have built and used the Adafruit press and the stealth press by Iconic Fab both are useable; Adafruit's is quite a bit of sloppy IMHO but useable, the stealth press is nice like the key chain return -- nice smooth movement.

Again, thanks on those recommendations and relaying your experience. Quite helpful and much appreciated!

RE: Makign holes for M4 Heat Set Inserts

Another two bits of advice for you. If you don't want advice that you may not agree with don't ask for it on a public fora, and if someone does post something you don't agree with you have the option of just ignoring it.

Posted by: @tango

This discourse sure has gone South fast.

I was rather disappointed that it didn't stop when I tried to say that's not how I think. I found it frustrating that wasn't enough.

RE: Makign holes for M4 Heat Set Inserts

Give it a rest already, enough is enough. What you are doing borderers on TROLLING, IMHO

RE: Makign holes for M4 Heat Set Inserts

Printed Solid sells Prusa products in the US.

RE: Makign holes for M4 Heat Set Inserts

Posted by: @eds_3d_odyssey

Printed Solid sells Prusa products in the US.

Thank you! I am now looking over through their site and shop for what's available.

RE: Makign holes for M4 Heat Set Inserts

You could always just use a standard nut pressed in from the back. No heat required. As per Prusa machine parts, pull the nut in using the screw from the reverse side. 

RE: Makign holes for M4 Heat Set Inserts

Posted by: @john-6

You could always just use a standard nut pressed in from the back. No heat required. As per Prusa machine parts, pull the nut in using the screw from the reverse side. 

I considered that. I was thinking of several similar possibilities, like using painter's tape to hold the nut into place, or try to reach in with my finger to hold it in place, but since the plate I'm working on is the back plate for a wall plate, so it'll go inside the wall, on the back side of the drywall, that makes it problematical. I thought, like you point out, that if it's held to the back plate in any way, once the screw thread goes through, it should hold the nut. But if I push the screw in a bit too far, or the thread doesn't line up at first, it means the nut could accidentally get pushed off. I figure painter's tape (or duct tape) might work, but if it gets pushed out of position at all, then it's a real problem to fix it.

While I figure the old trick of putting the nut on my fingertip, then carefully putting it in place and holding it in place with my finger, might work, it's awkward and might also lead to nuts just dropped into the wall.

RE: Makign holes for M4 Heat Set Inserts

If you make the recess just too tight to be able to press the nut in with finger and pull it in with a spare bolt the nut won’t come out. 

RE: Makign holes for M4 Heat Set Inserts

Posted by: @john-6

If you make the recess just too tight to be able to press the nut in with finger and pull it in with a spare bolt the nut won’t come out. 

I'm now working on something like this. Instead of a single normal nut, I'm going to do that with a t-nut. I figure that provides more sides to "grip" against the print, as well as some sharp edges that I might be able to get to dig into the PLA for added friction. I figure that's less likely to get accidentally knocked out of the recess I make for it than a normal nut.

RE: Makign holes for M4 Heat Set Inserts

@Tango - I think you are over thinking this. If they are pulled in tight the nut won't fall out. (This is how the Prusa printers are put together). But if you are worried add some glue to the nut as you pull it in with the screw  (before final assemble).

RE: Makign holes for M4 Heat Set Inserts

My concern is that the part with the nuts on it is inside the building wall, so if a nut falls out, it's gone. Losing a nut, by itself, is not a major loss, but if you're working on a project, trying to hold a plate in place on the wall side of the drywall, and another plate in place on the room side of the drywall, as well as trying to screw something in - including making sure it goes through the hole easily and mates with the nut, it's a 3 handed job being done with 2 hands - so it would be quite easy to push that screw in a bit harder than planned and knock the nut out.

I was thinking of glue, but that's also a bit hard, in such a small space, to make sure it doesn't block the hole for the screw or seep into the hole in the nut. A t-nut would also be easier to glue in place, since it'll be a lot easier to put glue on it on surfaces where it won't end up accidentally sliding into the hole.

I'm thinking it through carefully because I'm going to be making multiple copies of this and if I screw up, I'll have to deal with that screw-up a number of times.

RE: Makign holes for M4 Heat Set Inserts

The problem with those t-nuts with the 'spikes' is that as they are tightened the spikes dig into the pla like you want, however that has a tendency to break up the part along the layer lines and cause fracturing and part failure.

One of my reasons for switching over to using square nuts is that you can design the pocket for them so they slip into place sideways, if the pocket is long enough then you can cut and insert a thin piece of high density foam (like the type used in camping mats) into the pocket after inserting the nut.  That stops it from sliding out/moving when not engaged with the screw so there is no danger of it falling out.  The foam can be picked out with a needle if you do ever want to remove the nut at a later date.

RE: Makign holes for M4 Heat Set Inserts

The problem with those t-nuts with the 'spikes' is that as they are tightened the spikes dig into the pla like you want, however that has a tendency to break up the part along the layer lines and cause fracturing and part failure.

Thanks for the warning!

One of my reasons for switching over to using square nuts is that you can design the pocket for them so they slip into place sideways, if the pocket is long enough then you can cut and insert a thin piece of high density foam (like the type used in camping mats) into the pocket after inserting the nut.

I was going to do this with square nuts, but then ran into issues with the placement of the nuts and the length of the pocket. The foam would help a lot, but am I going to run into problems with the orientation of the object on the print bed? For example, if the pocket I need is 7mm wide and 30mm long, do I need to make sure the part is oriented so the printer won't be trying to lay down filament in the longer dimension? I realize PrusaSlicer tends to use diagonal runs, but I'm thinking that still might be something to be aware of.

RE: Makign holes for M4 Heat Set Inserts

Here is a pic of the base model I use as a negative to cut out the holes for a M3 screw with square nut (Boolean subtraction).  Side view in X and Y.  I can stretch the pocket to meet the outside of the thing I am cutting into as well as adjust the length of the screw sections to get the pocket where ever I need it to be and for the screw to reach.  In practice I has premade ones for the common screw lengths I use as well as variants for both countersunk (pictured) as well as cap head hex screws etc.

Note the gaps above and below the square nut pocket.  Those gaps are #~0.25mm thick.  S0 using a 0.2mm layer height it leaves a 1 layer thick patch over the holes automatically when cut out.  This means the pocket bridges if the part is oriented such that the screw is vertical.  So supports inside the pocket for the nut are not needed.  The distance is easily bridgeable.  If the screw is horizontal then with classic perimeters the hole is printed open and with arachne it might just do a very thin wall.  In either orientation you can just poke through with the screw once the part is printed and the nut has been inserted.  

Of course adjust the gap to suit your normal/desired printing layer height.

You just have to do a few sample prints in simple blocks with the cutter to get the tolerance right for your printer/material combo.  Once you do then you can just save and reuse the cutter as needed.  It doesn't need to be tight, as the foam when inserted pushes the nut into the end of the pocket and keeps it there.  

I've built up a library of 'cutters' for stuff I use a lot of, from screw, heat set inserts, electronics parts like speakers, OLED displays, leds, switches etc.  Theoretically I could export my cutters and use them as negative volumes in the slicer itself but its easier to position them properly in CAD.

RE:

When I suggested pulling the nut in with the screw I mean do it before you try to assemble the system on the wall. Put the nut on the tip of the bolt, tap the bolt with a lightweight hammer to temporarily hold the nut into the recess. The nut recess should be sized so that it is very difficult to press in by hand, hence tapping it in. Remove the bolt and screw in from the front until the nut pulls deep into the recess. There will be no alignment issues which can happen with the square nut slot (which is a good solution and maybe you need to use both techniques) . Reiterating if done correctly the nut won’t fall out upon assembly.

Posted by: @tango

My concern is that the part with the nuts on it is inside the building wall, so if a nut falls out, it's gone. Losing a nut, by itself, is not a major loss, but if you're working on a project, trying to hold a plate in place on the wall side of the drywall, and another plate in place on the room side of the drywall, as well as trying to screw something in - including making sure it goes through the hole easily and mates with the nut, it's a 3 handed job being done with 2 hands - so it would be quite easy to push that screw in a bit harder than planned and knock the nut out.

RE: Makign holes for M4 Heat Set Inserts

@Neophyl:

I have to go out for a class now, which includes over an hour of travel time, so when I get back, I'm sure I'll have thought of more questions, but here's the overriding one for me, now: You talk about orienting the cut out horizontally and vertically. I'm thinking more about whether it's north-south or east-west. In other words, say the screw is vertical, will it matter in any way whether the pocket stretches north-south (or front-back) or east-west (side-to-side)? Will the slicer and the printer still be able to handle it if it runs in either direction? In other words, it won't end up trying to drag the head across it the long way if I orient it in one of those directions and either one should work okay?

RE:

If you are bridging, you need to check the sliced model to ensure the travel is ideally across the short distance. 
Also whether you use pockets or recesses depends on the orientation of you print. 

RE:

Also without seeing your model isn’t there another way where the unit is inserted into the wall from the front only, that is one piece (even is manufactured in multiple parts and screwed together).

currently if you even need to take the front panel off you may have an issue where the inner unit falls inside the wall

RE: Makign holes for M4 Heat Set Inserts

If you are bridging, you need to check the sliced model to ensure the travel is ideally across the short distance. 

Okay - no problem. Just was wondering if it was something to watch or if slicers figured out issues like that on their own.

Also without seeing your model isn’t there another way where the unit is inserted into the wall from the front only, that is one piece (even is manufactured in multiple parts and screwed together).

I'm not quite sure what you're describing, but to hold the unit to the wall, there have to be parts behind the drywall and in front that are bigger than the hole made for the unit. So a one piece unit will be a problem - I need one piece I can put through the hole, which I'm thinking will be as wide as the hole, but taller than the hole, so it the back plate will back against the wall above and below the hole. I don't see how I can get that piece through the hole if it's connected to the part that goes on the front.

currently if you even need to take the front panel off you may have an issue where the inner unit falls inside the wall

I'm taking that into account. This is to hold a 3" (±76mm) flexible duct in place on both sides of the wall. While there are vents that do that, I need to easily detach the part inside the room for cleaning and other purposes and I haven't seen a wallplate for vents that does that. But I have taken that issue into account to make sure if it has to be dismantled, it can be, without anything being lost in the wall.