I just wanted to say that this is one of the best builds I have seen on here...mostly because you made the patterns for the castings. Talk about a custom build. Any chance I could get you to design, draft & make some patterns for some projects I have in mind?
Scott,
By incorporating sufficient draft, using multiple coats of sanding sealer
and block sanding the pattern to a fine finish, a smooth & finely detailed
casting will be produced.
Wyld,
With the information I’ll include in this thread,you should be able to
construct your own patterns. It is very rewarding to see the results of your
effort cast in gray iron, brass or aluminum. Give it a try.
Kuhncw,
The travel of the bridgemill is 18” x 12” x 9”. The Thompson rails are 1” dia,
and I selected 5/8” Ball screws with double nuts on X & Y.
The assembly drawings are posted for reference. The mill was originally designed as a 5 axis machine, but only 3 axis’ were included in the
prototype. I’m currently installing the new square steppers (425 oz”) & adding an additional axis.to rotate the spindle from side to side. To date, I have only machined wood,plastic ,brass & aluminum on this mill.
Thanks for the additional information. Nice machine. The drawings specify a 23 X 36 surface plate for the foundation. How do you drill holes and attach your rails, uprights, etc to the plate?
What do you feel are the pros and cons for the bridgemill design vs the knee mill design you are building?
Several details changed between completion the layout drawings posted and finishing the prototype of the Bridgemill.
The idea of using a surface plate as a machine base was discarded.
The “X” axis was mounted on a separate plate allowing changes in travel as required. Enclosed is a revised design using a 12” x 48” plate with .75” dia.Thomson rails mounted. The lead screws, motors & table are added to make up a complete single axis assembly which can then be secured under the bridge.
Exploring the pro’s & cons of the Bridgemill vs. Knee/Fixture mill designs and selecting the best configuration will depend on personal preference and your comfort level in using computer controls.
They are different animals...I like them all.
The Fixture & Knee Mills are manually operated machines until the CNC retrofit’s are installed, then they can be operated either using the handwheels or the Keyboard. The Bridge mill as presently configured, is strictly keyboard input.
I normally use MasterCam to compose the “G” code...unless it's a real simple task!
Was able to make some progress on the Knee & Fixture Mills this week.
The front & rear surfaces of the column on the fixture mill were blanchard
ground which made it easier to orient it for machining.
I chose to clean up the surfaces before cutting the dovetails.I cut the dovetails and the column base in the same setup insuring perpendicularity in the related asis'. Next i'll start machining the knee. I'm debating using the 6” x 24” table casting I have on hand or buying another ENCO cross-slide.
The next step in the Fixture Mill construction was to drill & tap 16 holes in
the Enco table and install the linear Rails. That worked out better than I
expected.
Hopefully, next week I'll be able to detail the saddle mod's & install
the linear rails on the baseplate.
The 4th Seal:
The linear's are THK, the Table that came with the ENCO Cross Slide is of excellent Quality.......What a Buy!!!
In order to determine the dimensions for the saddle I thought it wise to
assemble the table & leadscrew. I received the plastic 5/8-10 nut from Techno-Isel and wanted to check clearances between the nut mounting ring & top of the trucks when mounted on the rails. The LS nut mounting ring will have to be trimmed to lower the profile.
The X axis lead screw is of excellent quality and the ends are precision ground & threaded. However; the ends are secured in holes drilled in the cast iron mounting brackets. Since the Axis’ will be stepper driven, bearings are a must! Luckily the Brackets are 1 “ thick & when bored 26mm dia. x 16mm deep they will allow 2 bearings to be located on each end of the screw. Modifying the existing brackets worked out great because they are extremely sturdy.
Now on to the saddle design and selecting the method for mounting the motors.
Before the saddle could be designed, it was necessary to fabricate the lead Screw (LS) mounting bracket. A brass cylinder was turned to slip over the LS nut body. The end was tapped in 3 places to match the holes in the integral mounting ring of the nut. Two holes were drilled & tapped in the top of the bracket to attach it to the saddle.
The drawing of the saddle was carefully dimensioned because location of the trucks & LS nut mount is critical. The ball leadscrews on my BPT 2J are new with no noticeable backlash, so I was able to hold the dimensions I calculated.
The saddle was made from .625 thk CR steel. All holes were drilled & c’bored for m4 Screws.
The “X” axis was assembled and I cranked the saddle back & forth a few times
just to make sure I wasn’t dreaming…..Smooth as glass!!!
The hand wheel was installed on the right side of the table for manual operation.
The left LS mounting bracket was drilled & tapped in 3 places to attach the 23 size stepper motor mounting bracket. (direct drive)
Next time I'll have the "X" motor installed & get back to the Knee Mill Castings!
The two “X” axis motor mounting brackets were fabricated and one was mounted on the LS (Lead Screw) mounting bracket. I haven’t selected the flex couplings yet so won’t be able to design the spacers which connect the motor mounting brackets.
I decided to use the existing Enco cross slide base for the new “Y” axis. The base is very sturdy and originally supported the “Y” axis lead screw. Bearings on the lead screws are required for CNC applications so three bearings will be added.
The first operation is to reduce the footprint of the base with the Metal Cutting Bandsaw. 20 minutes and 3 cuts later the job is done. Then a bearing pocket was machined in the LS mounting bracket & the LS was turned down to add the
third bearing. The dovetails will be milled down to provide clearance for the linear rails. This machining operation will require the removal of my 6” Vise so
I can install the 2 Piece Vise. (the base is 12” long) At that time I’ll also
do all the machining on the Knee for that Mill.
There has been no progress on the Knee Mill because I’ve concentrated on finishing the Fixture Mill Cross Slide. I’m looking forward to connecting it to
one of my existing control modules and exercising the “X” & “Y” Axis”.
“Y” Axis debacle
Only after assembling the “Y” axis lead screw in the base did I realize that
It was damaged beyond repair. I should have examined it more carefully
because the “Y” nut was broken into 2 pieces in shipping. After berating
myself for my ignorance, I called Enco to obtain a replacement….they informed me it would take 6 month for a replacement to arrive here from Taiwan.However; if I sent the Cross Slide back they could replace the unit immediately.
After extensively modifying the Table & ancillary parts, that course of action was out of the question! I have already ordered a new LS & nut from another source.
“X” Axis progress
The “X” axis motor mounts were fabricated and installed along with the motor.
The whole assembly will be covered with a 6” x 6” aluminum plate.
Knee Mill Progress
The 2 piece vise was installed and the machining on 2 of the four sides of the KNEE was completed. Holes were drilled & tapped to provide attachment points for holding fixtures. The vise alone is not satisfactory and clamps were also required to bolt the knee to the Mill Table.
Now that the Holidays have come and gone, it’s time to get busy on the Mill Projects!
Not much progress to report since my last post.although I did buy several items which will move things along. Received another ENCO Cross Slide yesterday and have been busy tearing it down. So far no shipping damage noted. The table & base will be used to finish the X & Y axis for the knee mill.
I’ve used Ball Screws on all of my earlier projects, so it is with some reluctance that I chose to use acme screws & delrin nuts on these two projects. They will receive a vigorous workout on brass & aluminum and the results will be reported here.
I found some 12” ( ½-10) Acme leadscrews on eBay. They are machined on both ends & come with a sturdy Delrin nut,all for $18.
I’m also going to buy 2 Bearing Blocks for $12. Ea & 2 Motor Mounting Blocks for $23.ea.
These might be nice components for a home shop wood router.
Take a look & make your own assessment . They can be found on the eBay sellers list as: Premachine 2004.
Yeah I used that table for my mill, its fine for manual milling but it is sloppy. But the table surface is nice and flat and good for what your doing. I was hoping to see ya have a table casted, that would have been neat. Keep up the progress.
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.
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.
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)
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.