Z-axis Plumb

[Simops]

Ok at first I was not going to post this because felt, as this has been thrashed before (yes have read all the posts I could find), that I should be able to sort this out myself, but damn I'm going to ask for your advice anyway!

Its to do with my Z-axis. When I surface my spoiboard (use a 2.5" Amana RC2257) I get a slight ridge along the Y-axis. Pleae note that my Y axis is factory default X-axis (see pic attached). Brady says that if you can hook your nail it means the spindle is not square. I have measured my nail hook at 5 thou.

If I do as Brady says in one of his posts and use a square against the Spindle I find that this is not accurate for me as my Spindle does not have parallel sides, that is, placed against the left side (which is the side I used to initially square the spindle) shows dead square but then if I use the square on the rght side it is not. It should be the same if the Spindle has straight parallel sides, see pics bellow.

Ok so I decided to chuck in a 1/2" rod (that is a perfect straight rod) into the collet. And place a square up to that. It shows square all round. But then this may not be accurate enough reference as only over a small distance. So I can't rely on the use of a square to 'square' the spindle it seems so will use the surfacing as the guide. No ridges = perfect square.

Indications of having ridges along my Y axis says that I have to adjust the Spindle by unscrewing the 6 bolts holding the Spindle carriage and turn it right as I look at it to square it up. But of course there is no further adjustment available. Before I go to doing something radical as suggested by Gary to make the holes larger or Daniel's Tramel adjustment device....is 5 thou acceptable or am I being to pendantic by trying to get it less than 5 thou??

Thanks

Mike

[bleeth]

Hey Mike:

Bending a piece of rod to use it as a trammel chucked into your spindle is pretty much the best way to check accuracy of z alignment. Personally, if I was getting a ridge that I could catch my fingernail on I would be adjusting too.

[bob_reda]

It could also mean one of your squares are out. My guess would be the larger one, which is alot more common then one may think.

Bob

[damesqua]

Michael,
I'm new to forum, so I learning and may ask basic questions. But, did you level the table surface before checking for square?

[cowboy1296]

This really may not be addressing your problem. But when i had ridges in the past i found out that my rollers were out of alighment. Every time the edge of the table hit a high roller it would cause the table to rise creating the ridge. The rollers are adjustable and really a simple fix. Still working on my second cup so hopefully this made sense.

[Brady Watson]

Mike,
You want to first make sure that your spindle mounting plate is parallel to the extruded body of the spindle. If you measure from the body to the mounting plate, towards the top of the plate using the 'tail' of your digital calipers, and then towards the bottom of the plate to the spindle extrusion, that will tell you how it is running. Be sure the 'heel' of the caliper is square against the body of the spindle when you take your measurement. If you are within .003" of each other, then leave it alone.

If there is any gross deviation, you can adjust it by loosening the plate from the spindle, and carefully assembling it back together again (plate to spindle) while checking for parallel (use only one side of spindle/plate) as you tighten it down. Unfortunately that means pulling the spindle off...but it isn't too bad if you remove the stop bolt at the top of the Z gear rack. Then press all the way down and stick a strip of wood etc between the pinion & rack to hold into place while you pull the spindle off.

Then, when you remount the spindle to the 2x3 Z extrusion, drive the bolts in until they are just barely loose. Then get your (known good!) square and align your spindle to the table. This should get you really close to perfectly perpendicular. Surface the table and see how it looks. If you are still getting lines, 'read them' and adjust as necessary. When you've got it tip top, you shouldn't have to mess with it unless you abuse the tool enough to knock it out.

-B

[curtiss]

Michael,
I'm new to forum, so I learning and may ask basic questions. But, did you level the table surface before checking for square?

Your first table leveling effort is bound to have some ridges of some kind.

After your first leveling, you can lay a flat piece of something on the ridges, and then check the router for plumb with a stiff piece of wire taped to a 1/4" bit.

The tip of the wire should be the same distance above the table in all rotated directions.

[Simops]

Hey guys thanks for the advice......

To answer some of the queries ......yes I checked my squares and they are exact. I have a master engineers square that I know is 100% square and reference my other squares from it. I f I have a square that is not square I bin it! Yes the rollers are checked aligned.....I did this a few months ago when I put a new base on. Yes the table was re-surfaced before taking measurements and after any adjustment (although I have no more adjustment available).

The nuisance factor is the spindle body is not square so cannot reference from it.

One thing is clear from your answers is that the 5 thou ridges are not acceptable. I guess I was in denial because I set up my other machines to 3 thou or less so the CNC should be no different.....just looking at an excuse to get out of doing extra set-up work by hoping someone would say 5 thou is OK

Brady I'm going to follow what you said.....but I need to re-read it a few times to get my head around the process....

Cheers

[Brady Watson]

.005" out depends on how far away from the spindle nose you are measuring! Shorter bits with show less deviation than longer bits. My advice would be to get a 5" piece of 1/2" or 13mm drill rod (whatever your largest collet will accommodate), chuck it up tight and use that as your 'square reference'.

It is strange that your spindle body would be square on one side, but not on the other. Is it possible that your square was touching the cooling fan housing? That typically sticks out over one of the sides.

Don't drive yourself nuts with this. Get it close, and you'll be just fine on most jobs. You can be out several thousanths before you'll see any ill effects in wood. Only when you start doing large pockets (with large dia tools) will you see any deviation. It is also possible in denser materials like hard plastic & aluminum, but these materials can fool you into thinking you are out of whack if you encounter any kind of cutter deflection, so keep that in mind.

-B

[kubotaman]

An easy way to get the spindle dead on is with a Wixey Gauge. I put a .5 straight bit, as long as possible, into the chuck. I then clean the table off of sawdust and debris. Zero the gauge on the table then put it on the straight bit by way of the magnatized base. I have the bolts slightly loose from the backing plate allowing me to slightly move the spindle to get it to zero. When I have it correct, I then turn the spindle 90 degrees and take another reading. I have even used thin paper as a shim. This way it is quick and believe me is dead on if done correctly. It also allows you to run the spindle anywhere on the table and see if the rails are running correctly. When I surface my table it has absolutely no riges what so ever!!! Hope this helps you!