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Granite Gantry Rail Drilling Part 5

Granite Gantry Rail Drilling Part 5

Posted by Jonathan Gee on Mar 01, 2022

I SENSE A FUTURE THERAPY BILL WILL NEED PAYING SOONER OR LATER

Drilling Granite for Mounting Rails
[Part 5]

Posted by Jonathan Gee, 1st March 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...

Granite Hole Drilling Part 5

Here we go again. In this part I will be drilling the holes on the top and bottom of the granite block as you look at it mounted on the machine. These fixings will be used for the integrated structure that connects to the Y Carriage plates.

Image showing the first mehtod used for clamping the drill for cutting granite

I switched it up a little for these holes and broke out the 'The Little drill that could'. Again I took it off its normal base and came up with a clamping arrangement that worked sufficiently.Eventually i change this setup a little so i could get the full 95mm travel in just two positions that I could repeat clamp easily.

Image of jig with all bolts attached ready to check hole depths and binding.

I must not have taken a picture of this jig before I drilled the holes. Again i made a simple jig for scoring the hole locations with core drill. This just stops the drill from moving around when making that first mark, and I can use it in the future for transfering these hole locations. UPDATE: I found one below...

Photograph of the jig used to score the hole locations with the core drill.
Drill the granite with a 16mm diameter diamond tipped core drill.

This was the setup I ended up completing most of the holes with. I found that i didn't have to clamp it up that tight. Just sufficient enough to prevent the drill from tilting when I applied pressure. Some of these holes I managed to get down to 25 minutes per hole before the first core drill about had its day.The second core drill broke prematurely, but it was my fault. I was trying to hammer out a stuck piece of core and i fractured one of the teeth trying to get it out.

It was a hell of a messy job this part. I am not sure why really, but it seemed much messier than when i drilled the vertical holes in the gantry face. Maybe the cut i was getting with 'The Little Drill That Could' meant i needed to feed in more water. Because the frame of the small drill was much closer supported that the big drill leaning over, it was easier to apply a firmer touch.

Picture of the granite CNC gantry with all the top holes drilled.

Boom! Thats another 20 holes done! Sounds easy typing it like that but it was a solid two days job.

M8 bolts is all the top face of the granite.

I had got pretty handy by this time with setting the inserts and I could seat about 8 of them on a single cycle. But that was cutting it tight before the cement cured.

Close up of an internally threaded socket cemented into solid natural granite.
Linear image of the granite gantry with all the M8 bolts tightened up.

Basically i did nothing different on the bottom ecept for the fact that i taped up all the holes to prevent the threads getting block up with sludge and grit. After a couple days left to dry out and cure 100% I applied a large amount of torque to each of the bolts to check adhesion. I did have one come out. It must have been one that I completely forgot to blow out and dry because it was soaked in water inside and the cemented had not bonded. Or maybe it was some cement that had not mixed properly with the hardener. I am not sure, but applying a torque test certainly showed up the problem child. I just dried and cleaned this hole out and reset it.

After a cleanup looking quite tidy. You may wonder why I chose not to use more bolts in this end, but when it comes round to sharing the design for the gantry assembly you will understand how the support of this gantry is spread across all the faces of this granite block.

Progress does feel good though. Especially having not done anything like this before. I've said it before and I will say it again, you need quite a succinct plan for what you are going to do. I fyou tried to make this up as you went along I think you would trip over a lot of hurdles. I had created designs that included space and fitment for all the limit switches, for the glass scales and even made provision on the gantry for making fine adjustments to squareness etc. Oh, and don't forget cable and pipe routing. If you can model in 3D in CAD, do it and tweak your design until it sings to you.

Please feel free to leave any questions, comments or feedback on this build diary blog.



Originally Uploaded On: 01/03/2022

Last Updated On: 01/03/2022

Estimated Date Period: : 01/11/2020

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...

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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.