Contact Us    |    About Us   |   EMG Blog

EMG Precision Green Logo

Shop By Category

Shop By Price

Fine Tuning the Y Rail Granite Sides

Fine Tuning the Y Rail Granite Sides

Posted by Jonathan Gee on Mar 11, 2022

TIME TO GET A BIT MORE ACCURATE....

Granite 1st Stage Fine Tuning

Posted by Jonathan Gee,

11 Mar 2022


This is a privately funded project that frequently sees shortage of funds delaying progress, If you are enjoying this build diary and would like to contribute to the completion of this project and all the future guides and video journeys it would be gratefully received and spent directly on this project. Donate through PayPalMe Here...

Fine Tuning GraniteY Sides

So at this stage the rail inserts had been cemented in and I was ready to measure the comparable heights with something more accurate than the 600mm Digital Height Gauge that has a resolution of 0.01mm. The plan was to use a plunger style Test Indicator with a resolution on 1 micron or 0.001mm ( or 0.00003937" if you use that prehistoric yard stick of a system) in order to take a baseline of both the left and right rails, identify the lowest point, and then formulate my approach from levelling these puppies up.

If the need came to it, I could use the diamond tipped grinding discs in the pillar drill to lower the highest peaks. Then I I would use a couple grades of carborundum stones to fine grind and lap the granite down to as level and equal as possible. At this stage I had decided to target single digit microns plus or minus, and at a later stage I would revisit this process to get it closer.

Its important to note here that if you had not sunk your internally threaded sockets beneath the surface, this process would prove much more dificult to judge because you have to grind or lap the steel aswell. I had a couple inserts that were slightly proud but I used a 12mm drill bit to cut them below the surface. This seemed to work OK. Just remember to try and clear the threads out first before running a bolt down them.

I tried a few methods of mounting the Test Indicator. Above you can see the magnetic stand attached to my 600mm Digital Height Gauge. This setup didn't work particularly well so i change my approach as you can see in pictures below.

Remember to clean up after each grind and before each re-measure otherwise your results will be skewed.

Remember to clean up after each grind and before each re-measure otherwise your results will be skewed.

This is the kind of setup I used which proved much more stable. I experimented briefly with taking the measurements off the top of a mounted carriage, but it was fiddly to move both elements. I ended up taking measurements directly off the top of the rail.

These are the type of Carborundum Stones I used. Carborundum is the Trademark name for Silicon Carbide. It is an inorganic compund of silcon and carbon that has a  crystal structure similar to diamond and is almost as hard. It is often used as an abrasive for cutting, grinding and polishing.

These are the type of Carborundum Stones I used. Carborundum is the Trademark name for Silicon Carbide. It is an inorganic compund of silcon and carbon that has a crystal structure similar to diamond and is almost as hard. It is often used as an abrasive for cutting, grinding and polishing.


Its not really rocket science to be honest. I literally used the abrasive stones as sanding blocks. I took it steady at first making frequent clean ups and re-measures, I actually started to get a feel for how much pressure and how many strokes would take off. Prepare to do this process a lot of times. Again I used electricians tape stuck to the side to write on the variances in microns from my reference area, I took measurements approxiamtely every 100mm and wrote down the results, wiping them off and replacing after each measurment. I worked by working on the high spots gradually to balance them out. I did not really have to concern myself much with the squareness of the granite as it was pretty damn accurate after the grind, and the tiny amounts of material you remove with a flat stone laid across the 110mm width, there is little chance with a careful and even pressure stroke to alter this squareness with any significance. For Lapping I just used water that mixed with the silicon carbide to form an abrasive paste. For lighter cuts, I used a light stone dry.

Y Axis Granite Measurement off the Carriage

Upload 11/03/2022

Not the best of videos as i was trying to hold the camera and move the components at the same time, but you can clearly see that the results...

Y Axis Granite Measurement off the Carriage

The video was uploaded on 11/03/2022.

You can view the video here.

The video lasts for 34 seconds.

Granite Y Axis Measurement Video to 0 to 2 Microns

Upload 11/03/2022 .This video shows the level of accuracy achieved on the first stage grinding and lapping process the make the Y rails level with each othe...
Granite Y Axis Measurement Video to 0 to 2 Microns

The video was uploaded on 11/03/2022.

You can view the video here.

The video lasts for 19 seconds.

Continue to Electrical Bits & Bobs (Coming Soon)! >

Follow the Build on Instagram

Follow the Build on Facebook

Follow Us on LinkedIn



Originally Uploaded On: 11/03/2022

Last Updated On: 11/03/2022

Estimated Date Period: : 23/11/2020

This is a privately funded project that frequently sees shortage of funds delaying progress, If you are enjoying this build diary and would like to contribute to the completion of this project and all the future guides and video journeys it would be gratefully received and spent directly on this project. Donate through PayPalMe Here...

SUBSCRIBE TO OUR BUILD BLOG

Recieve our latest blog posts, build diary updates, weekly releases, offers, guides and more.

Thank you!

THIS BUILD DIARY IS ONLY HOSTED ONLINE BY EMG PRECISION LTD. IT IS A PRIVATE HOBBY PROJECT BY MYSELF, JONATHAN GEE. THIS PROJECT BLOG IS ONLY A DIARY OF EVENTS WITH SOME IDEAS FOR HOW I FELT THE PROCESS WENT WITH SOME TECHNIQUES I FOUND USEFUL. THIS IS NOT AT ALL AN OFFICIAL GUIDE OF HOW TO DO THINGS AND YOU SHOULD SEEK PROFESSIONAL ADVICE FROM COMPETENT PERSONS AND CONDUCT RISK ASSESSMENTS BEFORE UNDERTAKING ANY OF THE TASKS SHOWN IN THIS PROJECT BLOG DIARY.