Will build a Benchtop mill including Castings! Comments appreciated.

[CNCfun&games]

ZIPSNIPE: Thanks for the wake up Call!!

The rails & trucks were attached to the base casting.
The Y axis Truck mounting plate was sized and the holes were drilled
to retain the blocks.

Was unable to mount the lead screw nut. The nuts received from SDP – SI on the first order were easily installed . The nuts received on the second order were No Good.

Was able to find a NEW Brubaker 5/8 – 10 tap on Ebay, expect to receive it this week.
If I can’t correct the existing nuts, I can machine some DELRIN rod I have here to keep the project moving!

[CNCfun&games]

The 5/8-10 Acme tap was delivered & I was able to re-thread the Delrin nuts received from SDP-SI.

After running the tap through the two remaining nuts, the amount of chaff indicates to me that something was terribly wrong…..MFG & QC.

The support block was machined and the Y axis re-assembled. I installed a hand wheel and discovered the contribution that the linear rails & delrin nut makes in the smooth & effortless performance of the Axis. I then placed the X axis with motor installed (38 lbs) on the y axis
and repeated the movement with negligible difference…..Smooth!! Now I
can join the X & Y axis and see how things fit!!

Next comes some additional brackets & switches & the ENCO ULTRA Retrofit will be Ready to run!

[ZipSnipe]

Love it, Top Notch !!!

[foam27]

Yes, I agree, coming along very nicely....

[BMG]

Did you ever consider writing up a brief tutorial on obtaining castings from a local foundry?

Living within earshot of 2 foundrys and not knowing how to approach them has been a limiting factor for me.

I would certainly appreciate your comments and suggestions on hints, tips and tricks related to getting castings made locally.


Brian

[CNCfun&games]

Zipsnipe & Foam27: Your comments are appreciated …Thanks!!

BMG: I’m working on a new design which will require 3 or 4 castings
And I’ll discuss the pattern designs in detail to give enough information
to approach the foundrymen with confidence. I'll also critique my own
work, so my errors will be exposed!! Every pattern is a learning experience.


I will finish assembly of the cross slide this week & then resume the Pattern making effort including patterns for the new design.

Enclosed are concepts for the new Bridgemill Configuration.

[SSfab]

Do you give them a pattern of an acutal part? My local foundry needs a mold of the part so they can pour it with wax. Once the wax solidifies they de-mold it. From here they coat it with ceramic. They then melt the postive wax out to leave the ceramic mold. After all of this they fill it with liquid metal (whatever it may be) and then break the ceramic off.

Does you foundry do it differently?

[gotis]

Your work envelope is restricted

[jalessi]

SSfab,

Sand casting is very popular for big parts.

A wood form is used over and over verses lost wax.

This may interest you>

http://www.backyardmetalcasting.com/

http://backyardmetalcasting.com/forums/

Jeff...

[ZipSnipe]

Your work envelope is restricted

Looks fine to me Gotis, I fail to see the restriction?

[SSfab]

SSfab,

Sand casting is very popular for big parts.

A wood form is used over and over verses lost wax.

This may interest you>

http://www.backyardmetalcasting.com/

http://backyardmetalcasting.com/forums/

Jeff...

Thats cool, although I'm not looking to do this my self. That is another hobby i don't need.

[ihavenofish]

Looks fine to me Gotis, I fail to see the restriction?

he means clearance below the z rails. if the mounting was reversed - putting the rails on the moving Z part and bearings on the saddle you get alot more clearance which means the side gantry supports could be made lower and and therefore lighter and more rigid.

[BMG]

If you consider a tool in the collet, then the its tip should be approximately near the lowest point of the z carraige - perhaps that is why he considers no restriction?

[CNCfun&games]

Ssfab: See post 76 for a photo of a typical match plate pattern
used for “Sand Casting” gray iron.
What you described sounds more like an “Investment Casting”.

Gotis: the fixed element you noted is in the full down position.
It can be moved up with a series of holes in three 1 ½ “ increments.
The moving element of the Z axis will move the spindle down
6 + inches from any of four positions on the saddle.

Jalessi: Thanks for your contribution!
Have never seen those sites before.

Ihavenofish: the Z axis on my last bridge mill design was made in the
configuration you describe, however; the adjustability aspect of the new design allows for more part height under the Bridge.

Hi Guys,
The design is presently undergoing a lot of tweaking so keep the suggestions
and observations coming!

[ZipSnipe]

Hey the CNC machine looks great but what happened to your knee mill your building?

[CNCfun&games]

ZipSnipe take note:

Knee Mill Progress:

The knee was clamped to the mill table after allignment with the Vise half.
The “as cast” vertical surfaces of the knee were positioned on the table and
trued with an endmill before the dovetails were cut.
Then the column was installed onto the knee and Gib spacing was checked.
SO FAR! SO GOOD!

Ultra Cross Slide:

The X and Y axis’ were assembled and the results are shown below.
The Y axis belt and cover will be installed and then ….back to the Column Patterns.

Stay Tuned!!

[CNCfun&games]

HI All!

The Knee was clamped to the Mill Table and Half Vise.
Then the nose of the knee was drilled & bored to form the LS bearing pocket.

The 4 holes for the bearing retainer plate were also drilled & tapped.
The lead screw was installed & dimensions confirmed to
modify the standard “Precision Tech Machining” leadscrew.
The screw was shortened .5 “ and a 5/16-24 thread was added to the front
bearing journal to retain the bearing on the shaft. “Fixed-Simple config”.

The Cast Iron Saddle was placed on the knee to assess the machining
required to convert it from dovetails to linear rails for the X & Y Axis’.

The interior photo shows 2 threaded bosses and a triangular protrusion
which will mount the 2 bevel gears and the bearing pocket to angle the
height adjustment mechanism.
This is going to be a cut & try experiment.


Best Regards....W. Smith

[ZipSnipe]

Great lookin cast ya got there. Don't slow down keep 'em comin!!!!

[ViperTX]

Mr. Smith...kinda sounds like the Matrix.

Are these castings aged by the caster and what exactly does aging do to the casting?

Thanks,
Paul

[CNCfun&games]

Zipsnipe: still cutting material off the saddle, then I'll install the Trucks on the top & Bottom! will post Photo's then!

ViperTX: I haven't had any stress related problems on the castings.The subject has never come up with the Foundry.

The book says:

Stress Relief

Complex Castings of varying sectional sectional dimensions always contain
some casting strain. Where full strength properties are mandatory,
stress relief is recommended. Sometimes castings are “aged” or “weathered”
for long periods of time for this purpose, but a straight anneal treatment
assures complete removal of all pent- up stresses, where as aging &
weathering do not.

Stress Relief Heat Treatment

Stress relief anneal is important with complex castings, especially where
there is much variation in casting section thickness.

Slow uniform heating and cooling, approximately 50 to 100 degrees F per hour,
Is recommended. The former militates against cracking or warping of cast parts with high internal casting stresses; the latter avoids the reintroduction of casting strains from non-uniform contraction during cooling.

All stress relief must be distinguished from normalizing, since the maximum temperature is below the critical and ranges from 1000 Degrees F to 1150 degrees F.

Castings should be retained at this temperature for one hour per inch of casting section
and allowed to cool in the furnace.

CASTING DESIGN as influenced by FOUNDRY PRACTICE, Meehanite Metal Corp.