Printable View
Today I reworked the tapered Gibb strip fixings.
The original adjusters are totally naff allowing the the Gibbs to move, so they went from tight to loose as you reversed direction on the slide :nope:
To fix it I fitted 35tpi x 3/8" studs, screwed the adjusters on to them, (still sloppy) then bolted on end caps to pinch it all together... TIGHT :beer:
That's a good idea Robin, consider it stolen ;)
I have a small snippet of steel wedged between the adjuster and gib ATM doing the same job.
Next, tramming it 'cause it ain't square :thumbdown:
I chucked up a dti on a 9cm radius and measured to the bed at 4 points of the compass. Plus is a dip, minus is a bulge.
North 0.0"
East -0.004"
South +0.0035"
West -0.0087"
As I measured each point I drew a circle around the DTI tip so I could measure all four points moving the bed rather than the dti...
North 0.0"
East +0.002"
South +0.001"
West +.0025"
Yes, my column is out of square and the bed is a ski jump :nope:
RS do pre-cut shims with a MOQ of 10, so I ordered the 0.05mm (0.002")
Never tried this before, think I need 8 of them and a bed skim :whistling:
Did you use a parallel or similar between the bed and the DTI? It helps to smooth out bed irregularities.
My base was shimmed from new. The shims are brass coloured and less than 1 thou" (fitted near the bolts).
BTW Don't get too carried away - the head on these things can be flexed a few thou" with not too much trouble.
Quote:
Originally Posted by Robin Hewitt
I measured it two ways to compensate for the lumpy bed, but seem to have cocked up :nope:Quote:
Originally Posted by BillTodd
I reckon my -4 mils East measurement was actually a +4 mils, giving a +-6 mil East West tilt. I mean the tilt has to show even either side, doesn't it? :whistling:
6 mils over a 9cm radius translates to nigh on 0.3mm of packing at the column base, it's around 0.1 degrees out. I could see it was a bit bent when facing with larger endmills but didn't think it was that far out.
New plan. I have some 0.47mm brass sheet, I'll put a strip of that down the West side of the column base then shim the East side until it comes true(ish).
Not much of a plan, but hey, it's a plan. Now where did I put my piercing saw? :naughty:
Seems a long way out even for a Chinese tool. Have you checked the column and base for paint or rust intrusion? Is it bolted down onto something level and flat?Quote:
6 mils over a 9cm radius translates to nigh on 0.3mm of packing at the column base, it's around 0.1 degrees out. I could see it was a bit bent when facing with larger endmills but didn't think it was that far out.
You think I might have done a Hubble? :naughty:
It's a cheap mill bolted down to a cheap stand, I don't think level and flat were ever really part of the equasion.
Don't know about paint and rust either, I've never separated it. I will certainly have a look see before I put the shims in. Engine hoist job, wasn't actually planning to remove any of the bolts beyond loose. Don't want to risk it getting away from me :whistling:
How anal is too anal? :naughty:Quote:
Originally Posted by BillTodd
It is now 0.005 degrees out east/west and 0.002 degrees out north/south. Trying to resist going for better but whaddya do.
Started on attempt #2 at a faster spindle because the bearings are unhappy if I try to run the main spindle up to credible small tool speeds.
The fast spindle is an ER11 chuck fitted to the honking plate and driven using a 1:3 timing belt off the main spindle.
Same axial bearings and Belleville washers that have served me well so far, but less than the 1/4 ton preload this time.
I've been looking at those splendid tool location doo-dads based on an electrical contact between tool and workpiece. As featured on this very site :beer:
To that end I have added Tufnol insulators to the shaft housing. No electrical contact between tool and machine body until it hits the workpiece.
Spindle housing now bolted together and impossible to assemble :nope:
Have to add a bit of internal clearance so the pulley can get past the belt :whistling:
Measured the resistance top to bottom, slightly worried when I found 8 million Ohms then realised I was in the circuit. Moved fingers and it went away :rolleyes:
Stuck waiting for bits :rolleyes:
Did add an air driven spindle lock, now working on the suds nozzles.
Bill says it's a z axis lock and he's right :beer: