Will build a Benchtop mill including Castings! Comments appreciated.

[blades]

Very impressive project, fun & games! I like the home-brew castings. Especially interesting, since my dad was a pattern maker for Buick & Pontiac back in the day.

I think the delrin nuts will serve you well. As long as the nut is physically strong enough, the wear characteristics of it are phenominal.

I saw those same leadscrews & nuts on ebay myself... was thinking about them, but opted to try and use the existing leadscrews on my Harbor Freight mini-mill to see how that works out with my lower power motors.

[Oldboy]

CNCfun&games
Where did you get your ENCO X&Y table?
I have ben dealing with a seller on Ebay. Long story short TWO tables recieved to Date;both damaged at the same location.
So now im waiting for UPS to pick up this second one. To get shipper to send me another replacement.
Its slowing me down in my CNC MILL MOD.
And Pissing me off.

[stevehuckss396]

I am using the same table only KBC brand. This is my first attempt at a cnc machine so i wing it as i go. Ordered the ball screws yesterday and hope to have it moving under computer power 2-3 weeks. Then the Z axis (ugh)

[CNCfun&games]

Blades,
The 1st Photo in post #30 shows the method used to reinforce the Delrin Nut.
Guess I could draw it up in Solidworks & run a FEA but haven't done it yet!

Oldboy,
Try: use-enco.com

Model #AC201-2536 $121.95

stevehuckss396,
I've got a KBC catalog somewhere, I'll look it up.
The critical question: is it made in Taiwan.
Keep up the good work.....sounds like your' going first class.

W. Smith

[ViperTX]

*chuckle*...should I call you Mr. Smith?

FEA....oh, you are hurting me. So, be you a mechanical engineer?

This is one of the finest builds since 5bears.com's mill and Widget's CNC....don't know how I missed the beginning....guess I thought "who's crazy enough to build their own mill from castings and why would they do that...?"

Impressive, to say the least!!

You mentioned that you had a minimum of 5 castings made at a time.....have you thought of offerring those to the rest of us....

Just for grins.....what do people charge to make the castings that you've done?

[CNCfun&games]

Zipsnipe:
Be of good cheer! I did cast a table, see photo enclosed.
The thought of cutting “T” slots right now made my hair hurt.

ViperTX:
Thanks for your generous comments about the thread, my
purpose is to take the mystery out of this stuff & encourage more
hobbyists to give it a try. It’s great fun to make a pattern & see it
replicated in gray iron or aluminum.

Re: castings: I order 5 because there is normally no setup charge
buying that quantity. No problem disposing of any extra’s!

Cost: The last order averaged about $1.20/lb.

Now....back to work on the "Y" axis!!!

[davo727]

Hey nice work, Have you had any of the castings have big voids that made them not usable? If so does the foundry take them back and credit you? Thanks, Dave

[CNCfun&games]

Davo727
I've experienced surface imperfections caused by sand falling into the mold cavity. Never heard of a foundry not replacing a casting for this type problem.

Y AXIS PROGRESS

After saw cutting the cross slide base casting down to manageable size,
the saw cut surfaces were finish machined.

The next step was to bore the bearing pockets in the front & rear surfaces to
mount the lead screw.

Initially I decided to mount the linear rails on top of the dovetail, but decided to
move them down closer to the centerline of the leadscrew. This required the
removal of the dovetail to obtain the needed clearance for the trucks.

Picture 5 shows the extensive modification to the casting, the approximate location of the linear rail & truck, and the clearance and placement of the step motor. The aluminum piece is the beginnings of a motor mounting bracket.

A word on the castings:
All the castings on this cross slide were excellent in design & execution.
Generous radii on all intersecting planes and lots of draft. The interior
surfaces were as smooth as the exterior.
The castings were very machinable because of their fine grain.

BUT : I still hate to machine gray iron………..W. Smith

[georgebarr]

I plan on building a mill using castings someday. Can somebody recommend a book or DVD on metal castings?

I also read that there are metal casting services who will do the castings for you, correct? I am not to happy about building my own foundry and rather pay someone else to pure the metal into the castings I provide.

Thanks,

[CNCfun&games]

Georgebarr,
See my pattern making brochure on page 1, post #5 on this thread. The first 3 photos at the bottom are the 6 pages of the brochure and can be downloaded and printed out.
I have been using the same foundry for 25 years and I have never considered doing their job.

Fixture Mill
This week I concentrated on completing the “Y” axis.
Positioning the Y axis motor gave me some heartburn because I had to make sure the motor didn’t intrude into space occupied by the X axis assembly.
After looking at it for a couple of days, I proceeded to design the motor mounting bracket and the rear bearing block.
Enclosed are some construction details of the two parts.
The next task will be to mount the linear rails, motor, pulleys & belt.

Knee Mill
After cleaning & painting the Knee, I decided how the lead screw & bearing blocks for the “Y” axis should be attached. Luckily, the actual parts arrived this week and I had them to work with.

The knee will require a lot of effort to put it into an acceptable cosmetic appearance.
It was a loose piece (LPP) pattern, and not one of my best works. Lots of erosion on the parting lines because I didn’t radius the inside corners.

I made an LPP of a hefty angle plate (7” x 7.5” x11”) and cast it some time ago. It was a simple pattern with 5 degrees of draft, .125” radii in all the inside corners and several coats of sanding sealer with block sanding between coats to remove wood grain. The raw casting turned out well and was Blanchard ground on 6 sides to produce a reasonably good plate.

[AirHog]

How are those enco tables out of the box? I was thinking of using one for my X2 (manual) Are they pretty sturdy. I can pick one up over here at the shars warehouse for $99, add about another $100 for materials to build up the base and I'll have what i need in terms of size.

Otherwise I'll have to bite the bullet and throw in another $250 sell the X2 and get an X3.

Nice job on the castings by the way. What did make the prototypes out of? I've been trying to get my own castings going but other projects keep taking precedent. Never thought of just taking to someone else, guess i'm pretty stubborn. Seems that it costs roughly about the same either way when you consider fuel for the furnace, steel, time, not to mention i cleaning up sand

[CNCfun&games]

Airhog

The Enco Cross Slide is well made but has some serious shortcomings “out of the box”
Zipsnipe said his is “sloppy”, and I understand why!
See the Illustrated Parts List enclosed.

1. The leadscrews are of excellent quality, but are not riding in bearings.
This oversight can be corrected by boring bearing pockets in
the Longitudinal Screw Brackets (item 24) and the Transverse Screw Bracket (item 4)
The Base (item 1) can be modified to support the rear end of the leadscrew which
must be turned down to match the bearing (or bushing) you select. The NSK Bearing
I used is 6000ZZCE.
Dims: 26mm x 10mm x 8mm.

2. The acme nuts (5/8-10) are inferior and should be replaced with
Delrin nuts. The Y axis nut (item 3 ) is a press fit into the Base and is easily removed.
3. The X axis nut is cast into the Saddle (item 16) and will have to be
machined out and replaced.

Making these modifications will convert your Cross Slide into a valuable asset for manual operation or a future CNC retrofit!

The foundry I use casts gray iron & ductile Iron, my castings are Gray Iron.