Grinding Stone tick marks

[J-man]

I work with an old Grindrite ST 1800 XL machine and cannot seem to stop the tick marks from happening on the base.
They are few and far between on each ski but happens on every ski.

I've re-set or smoothed out the stone at least 8 times and it still happens.

Some notable mentions are that the diamond seems to have some give up and down due to the machine's age, so i've been pressing my hand down on the knob to get more consistent pressure from the diamond to the stone.
Also I've made sure to wipe the base of each ski before sending it through and even sprayed down the whole machine after cutting the stone to ensure no straggling bits are floating around and getting caught between the ski and stone.

And yes, I detune the stone with a block and even make sure to get any tough bits with a metal scraper.

ANY IDEAS?? please help, i'm going insane.

[evlskis]

I feel your pain. I wish I had a guaranteed solution for you. I happen to have a bunch of sacrificial skis - failed prototypes - that I run through to make sure I've removed all the grit trapped in the pores of my Grindrite stone. I end up doing this so often that I've considered making edgeless, ski-like objects to run through, just to put less wear on the stone between dressing it and actually grinding skis.

I don't know how much play you're seeing when you make passes with the diamond, but it may be that you're trying to remove too much material in one pass. Anything that causes visible deflection is going to risk shattering the diamond. Same with manually applying pressure. Let's just say I'm not on my first diamond. It took me way too long to realize that I needed to replace the screw drive the diamond runs along and I did some stupid things to try to force it to work. Not recommended.