Hello, many times the question on what kind of maintenance is needed for the Crossfire (Pro) has been asked on this forum, and it typically boils down to wipe it, clean it, lubricate it etc.
However, I am asking something different: after years of use, I am not exactly sure how to determine if the lead nuts are still good enough. Should I just replace them at a fixed interval? Few days ago I made a mistake and fed the X axis too much and the motor to lead screw coupler became loose. I fixed it but how do I evaluate if it’s better to replace it?? I noticed that on some of the carriages not all bearings touch the rails. So far no side effect (my cuts are accurate) but I should fix that - how?
I remember that when I first assembled the Crossfire PRO there was an “exercise program” to run, that was basically doing a diagonal. Is that something of value? I should probably check the squareness of a large cut, but how?
If I were to test, you would want a pointer device for your torch such as a laser or a mechanical pointer (similar to what @ds690 or @TinWhisperer or @Richarddbeck83 have shown).
Zero your torch on a mark somewhere near the center of the table. Now move your torch to each each of the 4 corners and tell the torch to “Go to work zero.” If the torch ends in acceptably close to this initial ‘zeroed’ spot then I don’t think you have anything to worry about.
I tried to lookup the laser indexing systems also using the names you recommended but today my search skills are apparently not great. Do you have a link?
So far I just three-dee printed a mechanical pointer that is better than nothing. This test is surely interesting but I still need to fix my carriages (not all bearings touching). I wish there was a checklist to perform every 6 months or so instead of waiting for a problem
Edit: I just got to thinking, since you are not indexing anything and only looking for a quick test of repeatability you could tape a tooth pick on the side of your torch and just use the toothpick for this simple testing.
It’s normal for some bearings to not be touching the rails at all times. The rails are not precision surfaces, so there is no way to have all the bearings touching the rails without causing tight spots that can stall the stepper motors. The assembly instructions cover this.
Simple test to ensure proper movement is to attach a sharp tip marker to your torch/holder.
Run equal distances in all directions on a flat sheet of steel.
Measure the distance traveled, and if the shape is true or not.
If you feel you need (or simply want to) replace parts like those plastic threaded couplers, just reach out to Langmuir to sell you a few. I have extras myself just in case.
I mean even as much as I clean my Z axis (and even making a video on its disassembly), the plastic threaded coupler showed lots of wear -
I’ll make a car analogy. Every so many miles or months, there are a number of checkpoints, each with a procedure to measure wear and an acceptable range for that part. It seems that such list does not exist for the Crossfire PRO and people just wipe it after use. I find this a bit surprising to be honest.
I do understand your point, and want to agree but can’t for this reason.
I would look at our stepper motors, couplers, and all other items as things we shouldn’t have to replace at any sort of interval, but should be prepared to do so if/when the time comes.
There are plenty of members still running original motors on tables they purchased when Langmuir first came out. All the motors on my current table are still originals, along with mostly everything else.
Using the car analogy it’s like trying to decide if you should replace your alternator or starter every 100k miles or so. They’re not listed as any sort of maintenance item, but they are susceptible to wear and tear and many times we won’t know when to replace it until it shows it’s ugly side and it dies.
Great example of this is one of my cars. I just replaced the original starter a few days ago and it was absolutely hell to do so (if you’re curious, it’s a 2UZ engine so feel free to look it up).
I have 367k miles on the car, and it’s all original and never pulled for a rebuild or anything. I maintain the hell out of it and everything works perfect (even the air suspension).
But I bring this up because, like our table, you just can’t predict when something will need to be replaced even if we’re meticulous about maintenance.
Here’s that video by the way of the Z axis assembly -
My table was down for an altogether different reason, so I took advantage of that and went through an entire tear down and reassembly going as far as replacing bearings in certain assemblies and more. It gave me a good idea of what wears quicker than other items (in my experience) but not enough to say if I should replace said items again in 6 months, 1 year, or 2 years. I just keep extras on hand now just in case.
Yes of course, I understand sometimes stuff breaks without warning or lasts for a surprisingly long time, but it does not mean that a checklist cannot help in minimizing issues for the larger population of users. During the Christmas time I will probably perform maintenance to the table and see how it goes
Most those users just call/email Langmuir directly (if they’re not panicking in the FB group).
Not everyone has a set of calipers to measure the 3 measurements found on a set of bearings. Outside of that and motor couplers (as far as generic parts go), everything else like those plastic threaded couplers are Langmuir-specific.
You could add a driver to your parts pile, they’re only $10 on Amazon. Motors too but I haven’t seen any with the same termination that Langmuir uses so you’d just have to chop it off and solder it onto a new motor.
What parts would your list consist of? I can’t think of many parts in general failing on these tables.
Drivers, motors, plastic threaded coupler, and bearings.
The bearings on the bottom of the Z axis assembly (the aluminum plate attaching to the gantry shown here on the left) are the only ones that really seemed to stick and could benefit from replacement. They receive all the crud that splashes up from air.
But since I have an extra Z axis assembly, I installed that instead. I’ll replace the bearings on the spare later.
I just change my company name to Beck Tools so my website is not ranked very high and can be a bit hard to find at the moment. Here is a direct link to the new site. Machine Torch Holder - Beck Tools
