Here we go again . . . MK4

**Nickhofen** · 10-09-2017

Top notch build!!! Thanks for taking the time to make all those videos also!

**Nr1madman** · 14-11-2017

You are just awesome:D

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**Nickhofen** · 14-11-2017

Awesome,I love the comments on the video also !

**Nr1madman** · 06-01-2018

You have solutions I would never think of.. thanks for sharing!

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**Nickhofen** · 06-01-2018

Very informative videos indeed!

**routercnc** · 06-01-2018

Thanks Nr1madman. Most of the ideas have been borrowed from looking at too many other machines!

Thanks Nickhofen glad you are enjoying it.

**Edward** · 06-01-2018

Hi routercnc,
Greatly enjoying your videos! One question, on your latest one, after cutting all the extrusion uprights, how did you machine them to be exactly the right length and exactly square?
Did you clamp them in the vice to be perfectly perpendicular and then machined the top, then turned over and machined the opposite end? Thanks.

**routercnc** · 06-01-2018

Originally Posted by Edward

Hi routercnc,
Greatly enjoying your videos! One question, on your latest one, after cutting all the extrusion uprights, how did you machine them to be exactly the right length and exactly square?
Did you clamp them in the vice to be perfectly perpendicular and then machined the top, then turned over and machined the opposite end? Thanks.

I actually cut them several months ago before I started making videos so what you see in ep10 is staged for continuity. But when I did cut them out I remember spending time setting up a stop and cutting a few practice ones to get them dialled in for length. The saw cuts pretty square and I did not need to machine them afterwards. Also the steel section which sits on top is not flat so there is no point in chasing tenths on the uprights. When it goes together I may need some shims and when bolted tight the top steel section may get pulled down unevenly. But this is fine as it will have epoxy levelling to get it all aligned for the rails.

EDIT !
Sorry Edward - went out to the workshop this morning and had a closer look and they do actual having machining marks on the ends, plus they have numbers on them (e.g. -3, 7, 4 . . . ) which are the errors in hundredths of mm at various places across the end on the total length. Sorry - so many parts I lost track there. Yes, I did machine them to final length.
I would have clamped them against the side of the vice and made sure they were flat onto the bed (as the sides are not straight/flat).

**Electroconducive** · 06-05-2018

Beautiful work as always.

What did you learn about the bubbles?

I saw in the video you used a heat gun to try and get rid of them.

Were you successful?

**routercnc** · 06-05-2018

Originally Posted by Electroconducive

Beautiful work as always.

What did you learn about the bubbles?

I saw in the video you used a heat gun to try and get rid of them.

Were you successful?

Answer is quite a lot! Although I had read lots about epoxy levelling on this site it is not until you do it yourself that you get a feel for it all. In short I made some mistakes.
It will all be in the next video but that will be some time away.

I checked the flatness and it was all over the place because of the bubbles. Where I had used the heat gun the most started to cure quicker which probably didn't help.
I tried to lap the surface back but it was taking forever and it was going to be tricky to ensure I kept both sides parallel to each other.
I think the epoxy should have been mixed slowly to avoid too many bubbles and then left in the warm bath to help some of them escape. Then pour slowly and use a stick to pop any remaining bubbles. The heat gun should be used sparingly if at all.
I had a long think about it all then took a chisel to it and took it all off. New epoxy on order plus some redesign of the channeling. I may even lay in multiple stages just waiting for it to skin over between coats. Not sure yet . . .

In short I'm back to square one but this needs to be right!