Lately some letters have been looking way off. Mainly As and Ts. They used to cut straight across the top and now they curve. I have already checked belt tensions, v wheels and pulleys. Any ideas?
(I’ll assume the T is straight in the design file 
)
If you grab the Vbit by the tip and wiggle it around lightly, do you feel any slop ?
If you do, does it also happen if you hold the router body itself?
When you say you checked V-wheels, did you check the wheels themselves (i.e. whether they might be damaged/cracked), or the eccentric nuts, or both ?
The design letter T is straight. The bit is not loose anyway I try to wiggle it. I cleaned the wheels and checked the nuts and all is good there. I used this same font before and the T was fine. I used another font and the T is straighter but they look similar as far as tool path goes.
See here the same font. The T is straighter so I’m confused on the amount of change between the two.
Did you check if you get he same curvy Ts if you cut them in different places of the work area ?
Just so as to provide a hint whether this could be a very local mechanical issue.
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I did cut a series of A’s T’s and I’s across a work piece 21” across. Same results. Even A’s became curved on the right sides and were always straight. Some letters in this I didn’t let finish so they look bad already and some are finished but they all cut weird. Zoom in to see what I mean.
It seems like Y moves (e.g. I’s) are mostly fine, while letters that involve an X movement have the problem. It could be interesting to try and cut the same letters rotated by 90degrees see if the defect appears on the I’s then.
Have you checked ALL v-wheels/eccentrics, including the Z axis ones ? (assuming you have a stock/belt Z axis)
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I will give that a try. I did cut a straight line along X with the Vbit just to see what would happen and it cut straight. I did check the Z wheels and eccentric nuts as well and they all seem fine. I do have the belt driven as well.
Mmmh.
It’s as if upon plunging, the Vbit moved up slightly, and therefore cut not as wide as it should.
It also seems like when the V-bit is plunging from left to right (when it cuts to left part of the top of the T) it bends towards the bottom, while when it plunges from right to left (right part of the top of the T), it bends in the other direction / towards the top. To me this means some kind of play somewhere.
What feeds and speeds are you using and what depth per pass? Sorry for the many questions, this is all with the intent to create an “aha” moment. Since the problem appeared suddently, with a font you had used successfully previously, I guess we should keep on looking for something mechanical…
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I have been doing 50 ipm 25 plunge and .1 cut depth. I also slowed it down 20ipm to see if anything changed. Same results. The bit I’m using has 3 flutes that manually entered but it’s the one I’ve been using. I also also tested this as tool #302 to see if it changed and it didn’t. I have a slo-mo video of it cutting if that will help but I can’t upload it here. The cut path it takes is from the center of the T and cuts right then goes to the bottom of the T moves up and then cuts the left side of the T.
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you could put it up on youtube or something if you have an account there ? or just compress it into a zip file if it’s just a matter of file format accepted by the forum (but then there is the size limit also). But I doubt we would see anything leading to the root cause…
I’m all out of ideas, I still suspect the Z axis/plate might have slop somewhere, but hard to tell from here. Usually when I reach this point, someone else comes in and drops a one liner with the solution, so there’s hope 
I would look closer at the fonts…the error seems to be pretty consistent. Take a look at the font at like size 52 and inspect it for any weird lines. I can’t remember the font I used but the N look fine but upon closer inspection it was wonky. Can you show the rendering vs the actual cut.
Also climb cut or conventional?
I’ve seen that before. It’s a cracked or chunk-missing v-wheel.
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Folks should always check the machine per:
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