Z-axis Plumb

[Simops]

Brady....wilco Roger. BTW if you look at my last pic on my initial post here I did in fact chuck in a 1/2" rod and placed a square to that.....that showed square but I still got the ridges. I think I will lay a 1" board across the table along 'my' X (which is the Y for most botters) and cut a series of squares out. Put my square to the sides and if square all round....leave it at that. If not I'll take off the spindle, re-seat it square to its backer and re-mount and adjust as you suggested. As you said if it is not causing issue than don't fret over it but its just that I like the idea of being as close as possible because once done I don't have to worry about it again

Daryl...I do have a Wixey digital angle gauge (I gather that is what you are referring to). I'll try it out as well to see what it gives me.

Thanks guys....

[Simops]

Thought I'd give an update on plumbing the z -axis on my Buddy 48 standard. ...especially for those new to the Shopbot like me (I think you stay 'new' to CNC for many years) I was finding that I would get ridges after surfacing that would hook your nails as you run it along the X- axis (Y-axis for you guys as I swaped them around for my setup). In the Y-axis (your x-axis) it was ridge less and smooth. See first post beginning of this thread.

So that meant that the spindle was not vertically plumbed to the deck parallel to your Y-axis gantry. The ridges indicated that the spindle had to tilt further to the right but I had already gone as far as the bolt holes would allow!

So yesterday had time to do some maintenance. I removed the deck so that I could get the spindle low enough to gain access to the top 2 bolts ( there are 6 holding the spindle). You have to remove the rack stop bolt first to allow the spindle to move down low enough. I then removed the spindle and had to then enlarge the 6 bolt holes to allow more movement for adjustment. Seems that they should have picked this up in the factory but obviously they do not fine tune it before shipping out. Also took this time to do a re-grease and oil the felt.

Now replaced the spindle, tightened only the top 2 bolts (because you won't get access to them again) and replaced the deck. I then used my 'Align-it Dial Indicator' (see pic below) to act as a trammel.

The nuisance factor was having to remove the dial indicator every time an adjustment had to be done because you have to lower the spindle almost to the deck to gain access to the 4 bolts ( forget the top two). There is a Forum member who has made an attachment so that the spindle can be easily loosened, adjusted and the tightened from the front....excellent...Shopbot should have done this.

Anyhow after a bit of to and froing I got it within 3 thou. Could have gone better but was getting tired of the tedious process. I then surfaced the deck by .05" and this time no ridges to hook your nail. Great....now to replace with new spoilboard and re-surface. The resurface went well, again no ridges. Not perfect mind you but how pedantic can you get....! I was happy that at least I'm not getting nail hooking ridges! Using the dial indicator I get, over 48", a max of 5 thou difference. Should I try to reduce that....maybe? But then I would need to get a better way to adjust the spindle like what the other forum member did. It should stay right for a while now but I don't think it would take much to knock it out slightly with use over time.


Cheers

[Brady Watson]

Sometimes the spindle plate is not 100% parallel to the spindle body, so keep that in mind. I've unbolted, mic'd and carefully retightened a number of them over the years to get spindles dead on.

You can get to the top 2 bolts if you remove the top stop from the gear rack (all the way @ the top of the Z rack - 3/16" hex key) and then pull the Z down. Then wedge something soft between the Z and the Z pinion to hold it in place so you can attach the spindle like a gentleman...

-B

[Simops]

You can get to the top 2 bolts if you remove the top stop from the gear rack (all the way @ the top of the Z rack - 3/16" hex key) and then pull the Z down.
-B

Yep did that Brady, but you have to remove the deck still to get it low enough.....that is a nuisance and unfortunate.

Cheers

[Ajcoholic]

if you are having a 5 thou high ridge, you are actually cutting a 2.5 thou high ridge which is amplified x2 - correct? Say I use my 1.5" diameter surfacer cutter, and I get 5 thou ridges... the high side is 2.5 up, the low side 2.5 down to give the measured 5 thou (assuming my overlap is zero).

so, over .75" the difference in height is 2.5 thou. Over the whole 48" width of the machine, it would be .16", or 5/32" out. That is less than a degree out of plumb from my calculations.

Now say you are cutting out material from sheet stock - is that going to matter? Probably not.

I had run my spindle hard and stalled out the cutter a number of times experimenting with deep, hard cuts in 8/4 hardwood. I could see my spindle recently cutting a little "out" when surfacing my spoilboard. WHat did I do? Loosen slightly the mounting screws, and tap the spindle with a soft deadblow mallet and re tighten the screws. re test cut. Repeated a few times until the re surfacing left no ridges.

SOmetimes I find trying to measure such things (with a square or pointer, etc) is an expercise in frustration, where as a littlew time spent "trial and error" gets you there fast.

What is important? Not measuring square. WHat is important is no ridges. So adjust in small increments until you get no ridges - then its as good as it will get!

[Simops]

Hey AJ that's what I ended up doing........my frustration though was that with the Buddy you can't get to the top bolts of the spindle mounting plate without having to remove the deck so as to lower the spindle down enough......
So to do trial error as you say means that I cannot tighten hard the top bolts because I ain't removing the deck each time I want to make an adjustment (especially 4 x 4 one).
Anyhow did the adjustment tightened the bottom 4 bolts and now no ridges I can hook my nails.
Oh the only other nuisance was that I had to oversize the bolt holes to get enough adjustment.....you think SB would have picked that up in the factory....obviously they don't plumb the Z accurately in the factory.

Hope you are enjoying better weather with Summer coming......it's **** here.....first snow in the mountains already!

[Ajcoholic]

but if you take off the powerstick, and put it back on it doesnt change anything settings wise.. so it is still relatively easy. I put a shop cart in front of my machine to take the weight of the table, when I pull it off but it still is a two person job with my 5' by 6' x 1 1/2" table top.

I found there was just enough slack in the bolts and homes to perfectly plumb my spindle. It is possible that the spindle mouting holes themselves vary by a wee bit, and also the shopbot holes in the plate vary a wee bit and if you are unlucky enough to get two at the either end of the tolerances - you might have to open the holes a bit to plumb it up.

I wont blame shopbot as they dont mount the spindle.

[Simops]

Hey I don't blame Shopbot as the final adjustment for the Z is from the end user. But as a manufacturer they respond to feedback, as I do (manufacturing flight training devices) always looking at improving our products, tweaking things to maintain customer satisfaction and therefore sales.

I feel that the adjustment of the spindle could be made easier without having to remove the deck. You are lucky if you have someone available to help....I don't really and my space is confined so it is a hassle getting the heavy deck off and on when setting up. Thankfully it is not a regular event. Although with basically 4 bolts holding the spindle I think one good knock and it would be out again. I also note from other users that I'm not 'Robinson Crusoe' with the 'running out of adjustment' bolt hole issue.

I grant you that machining wood it may not need as high precision but I machine mostly aluminium parts and so looking at best setup I can get. I'll admit that in hindsight the shopbot was not the best choice for what I'm doing but I wanted the best of both worlds on the cheap so working hard to maintain the highest setup precision I can get.

Cheers