Why do the drains clog?

Plotting my drain strategy, realized I’m missing one key piece of information:

For those with the stock drains:

  • In your estimation - why do they clog?
  • Do you notice the flow stopping because the screen gets saturated with chips?
  • With the screens clean - can the drains keep up with full coolant flow rate?
  • Do chips get clogged in the tubes beneath the drain?

All of the above. The center rear drain strategy works for me. Increasing the tube size on the factory drains to 1/2 would be my choice.


I suppose what I’m getting at is: is there a) insufficient screen filter area AND b) flow restriction from the small tubing?

Because if both of these things an and b are a problem, then just using larger tubes on the stock drain won’t fix anything, the filter screens getting clogged will be the bottleneck still.

If it’s only a, then more filter screen area is needed, and a single drain solution like in my other thread won’t work.

If it’s only b, then just larger tubing is needed and my solution will work.

Folks that are doing the long rectangular shower drains have some opportunity to protect against a and b.

It’s all that you listed above. Small tubes with tight bends. Screens that are too tight of a mesh to flow correctly.
Increasing the drain tube size fixes that problem.
Adding center rear drain with 3/4 bulkhead
Fixes the problems. All coolant goes down the drain.
That’s my answer.


It has to also do with distance of travel to the drains. Has more chips build up from cutting it gets harder for the coolant to get to the drains. This fills up the pan and float more chips to the drains and increase the damming of chips around the drain. Adding a drain close to the build plate and coolant will take the short path to a drain. Especially has chips build. It also less like to create a lake effect to float chips toward the drain because the coolant has and easy path to the drain. This was a big part of my thought process and why I did the two linear shower drains along the Y. This is also the direction that most chips and coolant get sent during mill operation. I took this a step further with my build and flush the coolant and chips down the drain into a larger contain that collects chips and filter the coolant back into the main tank.

Did you do a coarser mesh for that center drain? Why doesn’t its screen clog?

I use the #40 mesh ss screen. It catches the big stuff. I will send you a picture when I get to the shop in the morning.

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Looks nicely built. Thanks. Hope you don’t mind more questions- Did you put it towards the rear of the machine to keep it close to the coolant tank? Any additional filters in line?

My machine is #2. No one had any idea at the time that the drains did not flow correctly. I used a 4-inch coring bit to drill down through the epoxy and concrete. I fabricated a 4" of sch 80 aluminum pipe. I welded a bottom onto it and then welded a 3/4 bunghole on the bottom. I got a brass bulkhead from McMaster Carr. Glued the assembly in with liquid concrete and filled up the gaps on the sides. I then remixed epoxy to smooth out the surface.
I have zero problems anymore. Almost all the coolant goes right down the center drain.


I think you should get mentioned in the footnotes of the setup manual for your efforts. WOW!

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I just recieved my machine a couple of weeks ago and going thru all of the boxes I noticed that LS is still sending out the same drain systems. you would think with all of the problems with the drains listed in these forums, that would be one of the changes they would have made by now or even to include the 5th drain that is installed on the pre assembled machine.

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Have they given any detail on what the 5th drain looks like?

This is their version. I am not sure why they stopped including it in the newer MR1.

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That takes all the fun of making your machine your own. Most guys that buy Langmuir stuff cant leave things alone anyways, and we love making things better.

That’s all part of the fun and it makes you smarter in the end!
I’m sure at some point they will make the change!


That’s a thing of beauty!

The drains suck. Theoretically they are more than big enough but in practical use… nope. Feels like someone did some napkin calculations for raw flow but never actually created a feature qualification plan or verified it while using the machine for an extended period. The stock installation strategy doesn’t place the drains level so I find that two of the drains take all the flow while the other two go entirely unused until the basin starts flooding.

For me, I still get chips past the screen (likely during the process of cleaning the machine) and lodged down into the pipes. Eventually, the flow is so low that the basin starts to fills up and I’ve got coolant pooling up around my vise. Drainage at this point takes about 4 hours.

A 90psi blast of air into each drain outlet shoots the chips back into the working area (and onto the ceiling). If you fill the drain cup with coolant (I have a hose attachment) and it takes more than five seconds to drain, it’s time to blow them out.

If I were to design this from scratch, I would be using a coarser and better seated/sealed mesh over the drain with a large pipe (1.5"+ ID) and add a second device that sits on the coolant reservoir that contains a tall and fine mesh basket to be cleaned out daily. I’d even consider a disposable nylon mesh since the chips often entangle into the mesh and are difficult to remove.

I haven’t had too much trouble with the drains once I printed those TPU gaskets. I get a good 1/4” deep puddle over the whole surface if I’m running it full bore for any length of time, but as long as the tub is full it keeps flowing. Haven’t had a clog since I started using the gaskets. Before that I had to blow the lines out almost every time.

Can you point me to where the TPU gasket file is, I can’t find them on the forum. I see everyone mentioning them but can’t find the actual attachment. Thanks!