Lathe Bed Way Grinder

My Chipmaster Bed shows some serious wear on ways, approximately 0,5mm, 200mm from the headstock side. The tailstock slides are slightly better, but not good enough to use as reference. between the inverted V and flats of each slide there is an unused area, i.e. non bearing surface, I used this for baseline measurements, and could use it as reference surfaces for a grinder to run on.

The lathe bed grinder, is this possible? I do not know, judging by the comments on most forums, definitely not advisable. So what do you do when the cost of transport is just not worth it, and you still want a lathe bed to original tolerance?

Scrape the Bed? the bed is hardened and although I tried it with a tungsten blade on my BIAX, it will take forever.

One youtube contributor shows a method similar to scraping, but removing small buits at atime with a small dremel tool with a cutoff disk mounted. I will keep this as my second last resort.

The Plan

My plan is to use my straight edge, mount a carriage and possibly linear slides to it, fix a adjustable grinding spindle, then traverse the carriage over the bed in sweeps with tiny increments of the spindle in 0,05 – 0,09 mm.

Grinding Theory

Next questions which come to mind are surface speeds of grinding wheel, feed rate, dept of cut, wheel geometry and hardness, to name a few.

I found this short yet informative write up.

Wheel Geometry

I have been investigating on what wheel geometry to use, flat wheel, side wheel at 45 deg, cup wheel etc, the concerns are more forces exerted on the spindle and saddle which might cause vibration. Don bailey on youtube has some good advice on side wheeling. In the end I think the geometry of the spindle fixture on the saddle will determine the wheel type. The example above shows a flat wheel used in two modes.

Saddle design

I will base the saddle design on the classic lathe layout. In addition the spindle needs to be mounted rigid and straight yet be adjustable. I have a few layouts in mind and will have to consider each carefully in context of constraints, such as geometry, and benefits such as stiffness.

 

 

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