How to adjust spindle height for non-cylindrical spindle?

Trying to upgrade this 3040 router with a higher torque BLDC spindle for cutting steel. Besides having a higher 1.3 Nm torque vs 0.3 Nm for the stock spindle, more importantly, the full torque is available at 0 speed unlike induction motors. I made a plate with a bunch of screw holes to allow height adjustment, but even so, it's now a lot harder to adjust the height because I have to (un)screw 4 bolts, instead of just (un)tightening 2 bolts and sliding a cylindrical spindle in its collar. Also, it will cause the aluminum threads to wear out quicker.

What can I do? I was thinking something like a plate that slides on rails. Or would it be better to adjust the gantry height https://www.cnczone.com/forums/comme...ry-height.html or just raise the work?

I am not sure what the issue is, I never adjust the height of my spindle on my cnc router, that is what the z-axis is for. Could you explain why you are wanting to adjust the height?

I need to adjust it because the Z travel is only 80mm. The Z clearance from the T slots to the bottom of the Z axis is 125mm, so I can only use a portion of it. Some times I want the spindle to reach all the way to the T slots but this would be used rarely like for wood relief carvings since that will make the Z easy to flex. For cutting metal, I will have to raise the work.

You could mount a dovetail to the back of the spindle that slides into a dovetail mount on the Z axis that locks when it's in the right position.

I just don't think that machine has anywhere near the required build to attempt to cut steel. I wish you all the luck in the world if you make it work, please share your progress and post some photos of your results. Wood and maybe aluminum but you need a mill for steel

...just use a Sub plate riser

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Originally Posted by machinehop5

...just use a Sub plate riser

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He is already using one

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You could mount a dovetail to the back of the spindle that slides into a dovetail mount

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Very clever, but I don't think I'll be able to cut a deep enough dovetail channel without severe runout, unless I go very slowly. How would the locking/clamping work? I was thinking you would add 1 or more extra slots parallel to the dovetails. A screw would slide in that slot that could be tightened to clamp the 2 plates.

This was the design I was thinking before dovetailing. I would use wing nuts to easily tighten. Also, it won't wear out the aluminum threads.
https://www.cnczone.com/forums/attac...d=448116&stc=1

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just use a Sub plate riser

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You mean like this? Is the height adjustable? I don't want to get it for several heights.
https://www.cnczone.com/forums/attac...d=448118&stc=1

Wait, I can get most of the benefits of dovetailing with just 2 rectangular rails. Much easier to cut ! I'm going to do that. Thanks for the dovetailing suggestion. I guess that's the ideal solution

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Originally Posted by spacesaver

Wait, I can get most of the benefits of dovetailing with just 2 rectangular rails. Much easier to cut ! I'm going to do that. Thanks for the dovetailing suggestion. I guess that's the ideal solution

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Yes that is the way to do it, your motor plate would have the male dovetail on it and just a rail each side one fixed the other to clamp this does not have to be a dovetail, it can be just be a step which is easier to make in your case like sketch

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Originally Posted by coherent

I just don't think that machine has anywhere near the required build to attempt to cut steel. I wish you all the luck in the world if you make it work, please share your progress and post some photos of your results. Wood and maybe aluminum but you need a mill for steel

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x2 coherent ..good advice

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Originally Posted by machinehop5

x2 coherent ..good advice

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You can cut steel with a dremel, and very well, anything can cut steel, it's just how well and how efficient, most routers like this can cut steel but very poorly due to lack of rigidity and clearance in the slide bearing, backlash and a spindle not suitable to cut steel, correct those things and you can cut steel without any problems

On large fab work all steel, I use a Bosch hand trim router to cut corner radius and chamfer the edges, so anything is posable if you have an imagination and a want and need

I made the sliding rail. Much easier to adjust now. I haven't done any test cut yet.
https://www.cnczone.com/forums/attac...d=448406&stc=1https://www.cnczone.com/forums/attac...d=448408&stc=1
https://www.cnczone.com/forums/attac...d=448398&stc=1https://www.cnczone.com/forums/attac...d=448402&stc=1https://www.cnczone.com/forums/attac...d=448404&stc=1

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I just don't think that machine has anywhere near the required build to attempt to cut steel.

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I'm very aware and did succeed in cutting steel https://www.cnczone.com/forums/chine...el-router.html. You just have to go very slowly and cut near the XY corners where the rigidity is strongest. The biggest weakness is the twist about the x axis due to the 2 unsupported X rails. Replacing them with supported rails would be the next improvement. The spindle getting stuck was the biggest problem and snapped lots of end mills.

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Originally Posted by spacesaver

I made the sliding rail. Much easier to adjust now. I haven't done any test cut yet.

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The wing nuts are not going to do a very good job, you need a plate washer to cover the slot, stud to stud, at least 5mm or 6mm thick, then a regular washer and Nut, you need a solid mounting what you have only has 4 small contact points for clamping it, which will be able to flex when cutting

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Originally Posted by mactec54

The wing nuts are not going to do a very good job, you need a plate washer to cover the slot, stud to stud, at least 5mm or 6mm thick, then a regular washer and Nut, you need a solid mounting what you have only has 4 small contact points for clamping it, which will be able to flex when cutting

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And your tramming might be off a bit every time you adjust the plate.

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you need a plate washer to cover the slot

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That makes sense, but I don't recall in simplified physics, friction depending on the area. If the total clamping force is the same, then so should friction. Unless the ground is mud. This isn't a car stuck in mud is it? I tried finding square washers on McMaster, but almost all the sizes are way too big and not rectangular. I guess I'll have to make my own.

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And your tramming might be off a bit every time you adjust the plate.

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True, but that should only matter if you're cutting a very deep pocket right? I don't think I will do that.

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Originally Posted by spacesaver

That makes sense, but I don't recall in simplified physics, friction depending on the area. If the total clamping force is the same, then so should friction. Unless the ground is mud. This isn't a car stuck in mud is it? I tried finding square washers on McMaster, but almost all the sizes are way too big and not rectangular. I guess I'll have to make my own.


True, but that should only matter if you're cutting a very deep pocket right? I don't think I will do that.

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If you think this has anything to do with physics or friction you are mistaken, you don't want a square washer, just a piece of flat bar with 2 holes in it would be the correct way to do it

And yes traming is important if you want to mill a flat surface, not for how deep you go it's more about the surface flatness, pockets will be correct if you have it right for milling a flat surface :)