I’m trying to cut some patterns out of 23/32 ply. I always add a bit of extra depth to the cut to make sure I get through the material. But I can’t seem to get through it. My last attempt has the last pass set at nearly 28/32 and it still won’t go through.
I’m using the rigid router and the z pitch is set at default 3.17. Zero the z-axis at precisely the ‘stock top’. The connector on the z axis is tight and I can’t find any mechanical problems. If I change the pitch or keeping adding depth just to get through, I’m afraid I’m going to bottom out the axis and break something.
At this point I have a lot of ‘almost cut shapes’ that I can’t do anything with.
Any ideas on how to proceed with fixing the axis? Reinstall the axis and measure it myself?
Any thoughts on how to recover the work? I’ve only been moderately successful with this method. Usually things are just enough off, the pattern is sloppy:
a) home the machine
b) generate new gcode with single pass at additional depth
c) run new gcode
Two days and two sheets with nothing to show for it but sawdust and frustration.
Not sure what you mean by “stock top”. But if you are using the stock router and z axis and you have 3.17 as the default pitch. I’m thinking you need to zero the z axis.
Zero the z again, lift the router off the stock, move the z a fixed amount with the GUI. Measure how far the z actually moves, as accurately as you can (if you have a standards lab then just get it within a reasonable small distance (somebody on a 3D printer forun actually did work for one…). That should give you an idea where to look.
Wearing out the Z button on the router might cause this, likely to move the commanded distance when unloaded
By stock top, I assume you mean the surface of the stock that the sled rides on.
When you try to cut deeper, does it remove more material? It could be that the pitch setting for your z-axis is wrong, so it’s only plunging a fraction of what you are commanding.
That’s why measuring the actual movement would help, calibration error (likely non standard motor) vs mechanical problem. Stripped buttons are not uncommon.
However, nobody asked about a motor substition. Is this the stock Z axis motor connected directly to the router where the knob was?
At 28/32 (depth of the final pass) I am very very close to the maximum z travel. So, what I should have said is, I can’t set the depth of the last pass any deeper without a very real risk of reaching the travel extents (and busting something). The stock is only 23/32 so I should have cut through easily with a zero at the top of the stock and the final pass set at 25/32. This is what I typically have used. I kept increasing the final pass depth (zeroing before each attempt) until I reached 28/32 and still had not cut through. Don’t want to risk any deeper.
What’s odd (to me at least) is that it worked fine at 25/32 early yesterday. So I know the pitch was right. By my second batch, the problems began to occur. Checked the motor mount and connector. Everything is tight. I didn’t think about the button… maybe it cracked or broke… it wouldn’t wear out between one run and the next.
Measuring will confirm that it’s not traveling as far as commanded…I’ll do that tomorrow. It won’t answer why though… I don’t want to just recalibrate without knowing if it will happen again.
I guess to try and salvage the work I can see how much shank is left to extend, but I think I’m pretty short there too.
I didn’t think about the button… maybe it cracked or broke… it wouldn’t
wear out between one run and the next.
it’s incredibly easy to strip.
Measuring will confirm that it’s not traveling as far as commanded…I’ll do that tomorrow. It won’t answer why though… I don’t want to just recalibrate without knowing if it will happen again.
do you havea bungee over the top to take up backlash?
I guess to try and salvage the work I can see how much shank is left to extend, but I think I’m pretty short there too.
drill a hole though the slot that wasn’t cut deep enough and then use a small
flush cut bit on a trim router to go around the parts and cut them all the way
through flush with the part.
I would double check that your bit is long enough to cut all the way through. I have had a few times where I put my bit in the router and didn’t leave enough of it sticking out to be able to get all the way through.
I also sanded the groove in the housing and the housing down to 600 grit and removed all imperfections. You will also need to put some bungees or find another method to create some down pressure on the router.
I have been using the bungie since inception, but had not seen all the discussion on Z-axis fixes. I took a look at these just now… then went out and looked at my setup and the piece that the lead screw goes through is askew. I’ll take it apart tomorrow and see what gives. Hopefully the fixes mentioned will add enough life to the current axis setup that I can finish this little project and then maybe I’ll take a run at the “meticulous” Z-axis project… looks a lot more robust.
There is an art to getting the bungee tension right, and just the right tightness on the body clamp so the router moves good but is stable. I also use dry graphite lubricant on the router body some use silicone dry lube as well. I really can’t complain about my Z axis now it works well but is slower than I would like. I have been contemplating upgrading my Z axis but, in some ways it is trading one set of problems for another set. I think I may go for the 12’ top bar before I tackle the z axis. Glad to be of help if I can.
I took it all apart tonight and found that (I think) the spindle was binding in the base at the lowest extents causing the backlash to be applied. I sanded both the spindle and the inside of the base up through 2000 grit until it was a mirror finish. Coated both surfaces with T-9. This made the motion smoother, but it still took another half hour to tinker with the base clamp tightness and bungie strength to minimize x and y slop while still allowing the z axis to move. In the end, I was able to mill my parts, though there is much improvement to made. Where the bit raises and lowers to make holding tabs, there is enough slop that I get impressions of the bit in the workpiece. For this job I can live with that.
After I was done I came inside and ordered a Z-axis with leadscrew, anti-backlash and gantry on extruded aluminum. While I love DIY and budget projects, I want to spend my time creating and cutting and not fine-tuning a bungie cord every time.
Thanks very much to all who helped me find the issues.
@seware If you ordered the “standard” parts for the meticulous Z axis disregard. If not, would you mind sharing the details of what you ordered?
Also, here is the method I use for tension on the router, I don’t know if it would be useful for you but I am very pleased with the performance. I designed a router hat and use three small bungies.
My plan is drive the leadscrew via belt (like the MM build) using the standard z-axis motor with the ability to swap between pulleys while I experiment with Z speeds while using the same belt.
Plan A is to spring-load the idler pulley connected to a tee-nut in a Tee slot so that it tensions the belt regardless of the main pulley sizes.
Plan B - Put the the idler on an eccentric mount so that I can adjust the tension via the eccentric position.
Plan C - Hang the motor off an eccentric mount so that I can adjust the tension via the motor\pulley position (and eliminate the idler altogether.)
I’ll try to get a drawing together when I have settled on a plan.
Tried to look at the wish store page and got a popup that prevented viewing, and that apparently required me to give either social media credentials or sign up, in either case giving away my email address, before it would go away. No thanks