Sunday, January 2, 2011

A2ZCNC Leadscrews Upgrade - Fabricating the Z-Axis Antibacklash Nut Mount Part 2

Happy 2011!!!  I'm happy indeed as I get to spend around 4 to 5 hours in the shop, not mentioning the 2 to 3 hours yesterday night!  In fact, I just cleaned up the shop and decided to work on this post before I retire for the day.

Some update on this mod.  Finally managed to complete the Antibacklash Nut Mount and will be starting on the Motor Mount.

Starting the slot with a 1/2" endmill. 0.25mm per pass at 60mm/min.

Done finally.  Took a long time to open up the 38.5mm. I started milling down to the required depth of 13mm and move right at 0.25mm per pass.  Spindle speed set around 2000 rpm with feed of 60mm/min.

No radius on mine as I don't know how to create them yet.

Flipping the part on its side to mill out the shoulder.  Quite some vibration milling this side with same feed and speed. The part was standing too tall.  Should have use 2 taller plates to hold the parts between the vise to dampen vibration.

Major work out of the way.  Next with be the clearance and tapped holes.

After the mounting holes were drilled and tapped, the nut was inserted and fastened to check if the hole positions are correct.  Looking good.

Laying out the holes for alignment grub screws.  The center hole is for fastening the nut mount to the saddle.

Drilling from the bottom.  I just had my mill trammed and so decided to drill from the bottom to 1) test if my mill was properly trammed and 2) easier to clamp in the vise.

The 2 grub screw holes (or set screws as they are known here) were tapped 10-32.  Center hole drilled 5.5mm by mistake.  wanted 5mm...  On the far side, the hole was drilled and tapped for M5 per the plan.

Test fitting with the nut and the A2Z leadscrew. 6" caliper as reference.

From another angle.

As I still have some time left, I started preparing the stock for the motor mount.  The motor mount given to me free of charge by Tim of A2Z cannot be used as it didn't offset the stepper motor enough to use the nut mount with the bigger leadscrew.

2 options were available to me at this stage; I can either follow what Graham shown  on his pics by working on a piece of round stock in the lathe or to use CNC to profile out the part.  I went for the latter as I do not have aluminium round stock of 65mm diameter.  What I have on hand is a piece of 100mm x 160mm x 13mm aluminium rectangular stock.  Once the decison was made, I took out the hacksaw and started cutting out the stock.  Would have used my bandsaw if not for the blown motor (or controller).  Mike of SG Tooling is kind enough to volunteer to see if he can fix it.  I'm counting on him for that but, on the other hand, was hoping he can't fix it... why? because I saw a Taiwan bandsaw (Waytrain UE100S) which I like.  This little machine (in fact, it is bigger than all the stuff I have in my shop) can be used vertically and horizontally.  It comes with auto-feed and auto power off, features that make cutting up stocks to required size easier.  But it is going to cost me SGD837 including tax to bring it home.  Maybe I should just postpone this purchase and pray that Mike can fix the Proxxon bandsaw.

Lots of elbow grease was used, only to realize that the blade was blunt.  Changed it and the managed to cut through the 100mm stock.

Preparing for fly cutting.

It looks so much better now.  I'll be bringing this piece of stock down from the current thickness of 13mm to 12mm before drilling holes to hold the stock down for the CNC work.  The drawings were done in BobCad 2 nights' ago.

This is how the Stepper Motor Mount will look like:

48 passes for each feature... I'll standby my coffee and ebooks.
I'll find some time to finish up the conversion as soon as I can.  Got to shift my focus back to my day job since holiday is over.

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