Beavermill conversion to CNC

Hey everyone,

I am a metalworker professionally and as my hobby. I always wanted to have a CNC milling machine.
Hearing the prices of repairs on our CNC machines at work , I gave up my ambition to buy one.
Then I met some people who build their CNC by themselves.Then the idea came to me to rebuild my old Beaver Mill .
A decade ago I bought a Beaver Mill VBRP.
After standing in a corner of my workshop all this time, I put him back in the spotlights. The idea is to convert him into a CNC Mill.
Last Saturday I started cleaning him.
I will let you know how the rebuilding goes along.

Here are a few foto's from before the clean up;

Welcome to the mad house,
I think JohnS has a beaver mill or is in favour of them.

peter

That's a nice thing to have standing in the corner of the workshop (Actually, It'd be quite nice to have a workshop with a spare corner!)

I suggest you look at ball-screws rather than using the existing lead-screws (for X and Y), with servo motors, rather than steppers, for a machine of that size.

Are you thinking of motorising the knee or just the quill?

Hello everyone,
On Sunday I managed to partially disassemble the Beaver and to clean the table so it is presentable again.
I already had a ball-screw for the Z axis from a CNC mill that was refurbished.
And I am planning to change the X and Y axes with ball-screws as well.
Does anybody know which are the best axial bearings with zero tolerance
and preloaded so that I don't need belleville washers.
I don't know what they use in real CNC mills as axial bearing.
Kind regards ,
Andre.

Good pics Andre! I think a lot of the blokes on here like Beavers especially John! I am sure he will chime in with some advice soon.
Will

On sunday I did some more work on it.
I removed the elecktricity so we can put some new on later.
Disassembled the turret and cleaned the coolant tank which was full off slurry . Dirty work it was.
We also discoverd a tag with an award from the Queen.
And as you can see the year is 1967 so I presume it is build in the same year.

On Wednesday I cleaned the body with prepaint and put some paint on it.
yesterday we cleaned some parts off the turret.
Today we did some milling on the ram so if at a later date I want to make a toolchange or something else than there is already a plane and holes to bolted it on.
also on the rear I made some holes to connect a high speed motor.
Later today we painted the turred and started some milling on the table console .

Hi Andre,

That is some serious equipment! Thankyou for sharing this project with us - I will be reading along with interest...

Hello Tom,
Serious jobs demands serious equipment.
It is not always easy when you only have small machines.
Yet many of you are also making beautiful pieces with small machines .

Last week I had a lot of work with scraping the verticale slider mounting surface. on the link below you can see real pro's at work.
http://www.moriseiki.com/dixi/englis.../scraping.html
I did some assembling from the turret.And I found a protection for the Z axis.

Hello everyone,
Today I did the scraping of the X axis.
I've needed the whole day for it and tomorrow I will also have a few hours
to do before it is ready.

I'm still not done scraping on the X axis it takes more time than I thought
anyway I continue until everything is straight.
This week I am planning to order the servo's This week from Zapp automation
I think the set servo motors from 1000 watt hopefully they are strong enough

It's looking good Andre,

I've never owned a machine with hand-scraped surfaces - will do soon though I hope. Just out of interest, the X axis bearing surfaces look quite long (it looks maybe 1500mm?). What are you using as a flatness reference to scrape this surface?

Hi Tom,
It is 1400 mm long and I have a special tool that I can use .
I will tomorrow make a picture and show you.

Tom ,
This is the tool that I talk about .
There are many shapes and designs available.
Or if you are in possession of a flat table, you can make one yourself.
Are you planning to scrape your own machine?
I can only say one thing "patience"

Hi Andre,

Thanks for the pics. Actually I was just curious about how to stabilise the flatness over such a long and thin shape. Of course a triangular section is obvious to me now! :)

My machines do not yet deserve scraping. In the UK we have a phrase "making a silk purse out of a sow's ear". It means that I could try for a long time with lots of sewing to turn a cow's ear into a silk purse. In the end, maybe it would look a bit like a silk purse. But actually it would always be a sow's ear!

It's the same with my cheap lathe! :) I'll save the scraping for another lathe...

I had thought about making a small flatness reference by scraping 3 plates into each other - but that would take a long time too!

I have spent the last days designing the axial bearings

and have done research for which

configuration I am going to use.
I had first thought of using a ZARN type of bearing .

But they were too expensive .
So I made my own a design with two axial needle bearings and one radial needle bearing.

Then I have the same result as the ZARN bearing.
I can preload them as I want.
Today I received the CNC handwheel.

Hello everyone,
We finally have finished scraping bearing surfaces on the X axis.
I decided to start from the basics because I had discovered that the table
was bend at the ends about 0.4mm on both sides.
I will show pictures of what I did to get it right.
Maybe something that someone can use it for his own project.
The first thing I did was to facemilling the carrier.
Then I milled the pigeons tail .
Then I finished it on the granite block with the scraper.
So this is straigth.
I will show you the tools aswell.
1 small scraper and 2 larger tools.

Then I focused my attention on the table and have them placed on the milling table with a hoist because it weigh about 150kg and that is a bit heavy to manually manipulate.But first I have them measured and marked points with the correct height and recorded them on the piece.
I then aligned them both height and direction .
Next I face milled both sides and the top because the top surface was not straight olso.
After aligning the table under the correct angle with a 3d measurment device I milled the pigion tail .
Later I scraped the surfaces again .
The end result is a maximum of 20 microns difference over the full distance 1420 mm
both the flat faces and the pigion taile.
For checking the flatness I used a clock and a triangle block for scraping and for the pigion taile a micrometer and 2 cilinders .
And I use for scraping the Prussian bleu oilpaint to see what I did
otherwise you will not know where to remove matarial.

this is the triangle schape

Thank you for great report and pictures.
I am enjoying it immensely even though I know that I will never be able to do the same for my Bridgeport :sad: (not enough skill and no access to the kit you have).
Look forward to CNC Beaver :clap:
Chris

I'm glad you find it useful chris .That is why we do it .
In the past I have often made use of forums for my projects and am happy to give something back now I am working on a project.
Thanks for the feedback chris.

I found a nice link about how to make a leadscrew cover yourself .
www.ixen-cnc.com
Only I do not know what to use as material.
Has anyone a Suggestion?
Readily available and inexpensive.

Quote:

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Originally Posted by Andre

I'm glad you find it useful chris .That is why we do it .
In the past I have often made use of forums for my projects and am happy to give something back now I am working on a project.
Thanks for the feedback chris.

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I definitely agree with this sentiment. :clap:

Quote:

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I found a nice link about how to make a leadscrew cover yourself .
www.ixen-cnc.com

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Andre, I made one of those covers for my mini-lathe once. In the end I didn't use it, but it was a very interesting excercise in origami! Definitely try with paper first! It was tricky!
I used some plastic from a craft shop (about the thickness of the thickest plastic wallets you can buy from the stationary shop). For your big machine you would need something thicker, but be careful that it will not crack while flexing.

I am just thinking out loud - you could also cut the flat areas from thin metal, and use thin neoprene, or canvas for the hinges.

Hi Tom
This is maybe a good idea but I think using denim and saturated with epoxy
and then in a mold as it is almost cured so the hinges can still be well formed
but in any case a good idea
Kind regards.
Andre

Hello Everyone,
Eureka finally done with scraping I was almost thinking this is the never ending storie
all that scraping.
In any case, it ended well and everything is within the predefined tolerance 20 micron for the X axis 10 micron for the Y axis and 15 micron for the Z axis
I think that meets my requirements.
Good advice for everyone who enters the challenge of schraping
are aware that it will take longer as you think!!!!
It is like the medieval monks and the scriptures that they have made.
Now I can finally begin on other components
Kind regards,
Andre

Looking forward to the new pics Andre !

Quote:

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Originally Posted by Tom

I am just thinking out loud - you could also cut the flat areas from thin metal, and use thin neoprene, or canvas for the hinges.

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I have looked into this as well Tom, liking the idea of thin metal for the flat areas, what about some sort of sticky tape or sticky cloth tape to make the hinges and join it all togther :cool: ?

hello andre
just a note to thank you for such a detailed build thread:clap::clap::clap:
as i am just an agricultural engineer, could you tell me more about "scraping" is it to take high spots of of surface if so how do you find them engineer blue?
i am facinated at the work you have put into your mill and i would love the knowledge you have.
I'll just keep repairing tractors with my big hammer:heehee:
:beer: Tom

Scraping is used to get any surface flat using engineers blue and an other flat surface, the one you scrape will end up as good as the flat you use.
Hand scraped surface plates are made in 3's, done in a round robin mode which is reputed to give the flattest plate available but at a very high cost!

Peter

This is explained corect by Peter.
The flat that I use is first checked on a granite measuring block as you can see on the previous picture 's.
Here is the latest series of photographs of the scraping.
As you can see the final scraping is for the oil .
I've scraped the sides of the Y axis but I forgot to take photographs.
I wish the best for the new year to everyone that you have a creative year.
Kind regards ,
Andre

Since everybody likes photos,here some pictures of the changes to the knee.
Important is a good arrangement of the workpiece and a proper alignment so the error margin is as small as possible.
It is important that you make a plan off attack .
A strategy of how to start your project which consists at first of making a list that says what all needs to be adjusted and which alterations you want.

In this case I want some adjustments related to central lubrication system because original grease was used instead of oil to lubricate so therefore
it is necessary to drill new channels.
Also to support the Y ballscrew it is necessary to make an opening where a custom bearinghousing can be mounted.
Also a balancing weight is needed to support the weight of the knee to compensate otherwise I think the servo motor will not long survive the abuse.http://www.google.be/images/cleardot.gifhttp://www.google.be/images/cleardot.gif

The last week was one of heavy lifting the maneuvering of the heavy component was not always easy if you are working alone two hands are not always enough
and you must improvise.
The next thing I do is start going to make the smaller components.
Do You want pictures of the parts alone, or also the making of the parts themselves ?
Kind regards ,
Andrehttp://www.google.be/images/cleardot.gif

Hello everyone,
Today I started machining the first part of three which the servo motor of the Z axis will hold.
The first part is the base plate which directly on the knee is assembled.
I prepared the pocket to fit the base plate previously.
containing 6 M8 holes and two 8H7 holes for clevis pins to keep everything in place.
I used a piece of aluminum quality 1.6082 T6 ( T6 is the treatment the aluminum received) so it is good for milling.
First I put my vise on the table and aligned it properly .
Than i machined it in the proper order in this case first the bigger side
than I turned it around and put a cylindrical piece between the part and the vise so it will be square and did one small side.
Then I did the facemilling on the second small face also with the cylindrical piece.
and after that the second bigger plane and OK.
After that i took an endmill and did the milling off one side .

I want the edges to be round so i am going to mill some rounds on the corners.
The first thing i will do is make two small center drill holes on the positions off the center off the radius.
But first i have to choose a workpiece zero point.
There are several ways to find an edge you can use a piece of paper ,a cylindrical piece off metal which is painted with a color marker ,, or a wiggler center finder is a tool used in the spindle of a machine such as a mill. The device is used to accurately determine edges or markings and therefore the center of a workpiece or a previously machined feature during the set-up phase of a machining operation.There are also several 3d edge finders mechanical and elektronic.Here are a few .

Now I will locate the center off my milling table and make it zero X and Y on the DRO because I can use my table as a rotary table (so if you have a rotary table the result is the same) if it is done I put my workpiece on top of it and use pointed pin to find the previous drilled center holes.
If done so see that the vise is fixed .
I use a roughmill first and later an enmill for finish the rounds.

After the rounds I rough out the slab and finished whit an end mill later I made two chamfers by rotating the table 45 degrees.
After that I drilled the holes and OK
Thats all for today.

Hi Andre
great pictures,i greatly admire the job you are doing to your mill:clap:
you must have put in a lot of man hours!!
just a quick question when scraping the slides how did you get both sides to match as you would not have been able to sit your straight edge directly onto them because of the dove tail?
might seem like a silly question but i was just curious as i am no enginner:redface:
:beer:Tom

Hello Tom,
first of all there are no stupid questions.
We started with the support for the table .
As you can see on the pictures first I have the upper surface with a facemill straightened and next the dove tail .
I started scraping this section and than after the milling on the table I checked how far off straight she was on my granite measurement block (1,5m*1m)
as you can see with a dialtester and after scraping and measuring I used the support it self to check for flatness until within the tolerance.
Is that what you wanted to know?http://www.google.be/images/cleardot.gif
Kind regards ,
Andre