{"id":180,"date":"2010-02-13T11:52:11","date_gmt":"2010-02-13T16:52:11","guid":{"rendered":"http:\/\/freemansgarage.com\/blog\/?p=180"},"modified":"2021-05-05T07:02:03","modified_gmt":"2021-05-05T11:02:03","slug":"my-homemade-cnc-mill","status":"publish","type":"post","link":"https:\/\/www.freemansgarage.com\/index.php\/2010\/02\/13\/my-homemade-cnc-mill\/","title":{"rendered":"My Benchmaster CNC Mill"},"content":{"rendered":"

I currently have many tools in my shop.\u00a0 My favorite one is the CNC mill I built from an old 1954 Benchmaster mill.\u00a0 It’s heavy duty and very rigid.\u00a0 It works excellent and I run it with Mach3.<\/p>\n

\"\"<\/a>
Original mill before CNC conversion<\/figcaption><\/figure>\n

The mill is old and uses worn out ACME lead screws.\u00a0 This is not ideal for a CNC machine so I had to upgrade the lead screws to ball screws.\u00a0 I bought a length of 5\/8 ball screw rod and two Thomson ball screws from Mcmaster Carr<\/a>.<\/p>\n

\"\"<\/a>
Thomson Ball Screws<\/figcaption><\/figure>\n

I had to make an aluminum adapter to attach the ball nut to the table.\u00a0 So far it works fine and aluminum seems to hold up well.\u00a0 The nuts did not fit well in this mill.\u00a0 I had to modify the mill table by machining off about 0.250 inch from the underside to allow for clearance for the nut.<\/p>\n

\"\"<\/a>
Ball Screw Adapter<\/figcaption><\/figure>\n

Connecting the ball screws to my existing handles and using my existing table bushing was important so I machined an adapter that is identical to the fitting on the end of my ACME lead screw.\u00a0 I used two set screws and clamped down on the ball screw.\u00a0 This was my cheap alternative to buying the very expensive ball nut mounts.\u00a0 So far I have had no problems with this setup and it has minimal backlash.\u00a0 Some day if I ever wear out the bushings I will just CNC a bearing block.
\n\"Ball<\/a><\/p>\n

\"\"<\/a>
Steppers with a 2:1 gear reduction<\/figcaption><\/figure>\n

Now that the ball screws are all installed I had to buy some stepper motors.\u00a0 I bought 3 Keling stepper motors from Dan Mauch who owns\u00a0 Camtronics<\/a>.\u00a0 He helped me pick the correct size steppers for my machine.\u00a0 Dan was a great help and gave me a lot of advise on my setup.\u00a0 The X & Y axis ended up with two 385 oz-in steppers with a 2:1 gear reduction and the Z axis has a 495 oz-in with a 2:1 gear reduction.\u00a0 They are plenty strong enough and I can get 50in\/min rapids with ease on the x-y and about 20in\/min on the Z.\u00a0 That’s fast enough for me.\u00a0 I also extended the shaft so I could attach my original handles.\u00a0 Now I can still use it as a manual mill just like before.
\nI had to make all the mounts and I bought the timing belt and pulleys from McMaster Carr.\u00a0 I decided to go with belts and not direct drive because belts are very forgiving on the install.\u00a0 Belts still work very well even if you make crooked mounts and your holes are not perfect.\u00a0 It also allowed me to use smaller (hence cheaper) stepper motors.\u00a0\u00a0 There are lots of places online that sell motors.
\nHere are a couple pictures of the Z-Axis mount. There was no real place to drill hols so I made a clamp to clamp onto the Z-Axis shaft support. It works great.<\/p>\n

\"Z<\/a>
Z Axis Mount<\/figcaption><\/figure>\n
\"Z<\/a>
Z Axis mount<\/figcaption><\/figure>\n
\"\"<\/a>
Making the stepper standoff mounts<\/figcaption><\/figure>\n
\"\"<\/a>
Mill Fully Converted to CNC<\/figcaption><\/figure>\n

Now that the mill is fully converted.\u00a0 I needed a way to control it.\u00a0 I ended up buying a Gecko G540 controller complete with box & 36v power supply.<\/p>\n

\"\"<\/a>
Back of Controller<\/figcaption><\/figure>\n
\"\"<\/a>
Front of Controller (I added the labels)<\/figcaption><\/figure>\n

The controller was complete with power supply, cooling fan, power switch, & motor disengage switch.\u00a0 It works perfect and was worth every penny.<\/p>\n

\"\"<\/a>
CNC Mill complete with Controller & PC running Mach3<\/figcaption><\/figure>\n

I currently run a demo version of Mach3 to control the CNC.\u00a0 It is a really nice piece of software.\u00a0 I also tried EMC2 which runs on Linux and can be downloaded free at www.linuxcnc.org<\/a>.\u00a0 EMC2\u00a0 also is nice and does not have the 500 line limit that demo version of Mach3 has.\u00a0\u00a0 I have not played with it too much but you can run it off a CD-ROM without installing Linux permanently.\u00a0 I plan on using it more this year.<\/p>\n

<\/object>
\nHere is a video of it engraving.<\/p>\n
\"\"<\/a>
Finished tool with engraving.<\/figcaption><\/figure>\n

Here is the finished engraving.<\/p>\n

Here is the complete McMaster Carr\u00a0 parts list:
\n14 Tooth Acetal Pulley\u00a0 (3) \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 57105K14
\n28 Tooth Acetal Pulley\u00a0 (3) \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 57105K24
\nUrethane Timing belt (3)\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 1679K21
\n5\/8 Ball Nut\u00a0 (2) \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 obsolete – 5966K16\u00a0\u00a0\u00a0 (New number – 3405N079)
\n5\/8 Ball Screw\u00a0 (2 feet)\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 obsolete – 5966K261\u00a0 (New number – 3405N007)<\/p>\n

The motor mounts are all homemade out of 1\/4″ Aluminum Plate.\u00a0 I also did not use the expensive ball nut mounts.\u00a0 I used the standard bushings that were in the mill table and the standard anti backlash nut.<\/p>\n

\"Added<\/a>
Added pulley covers and a light.<\/figcaption><\/figure>\n

Here is an updated picture of my mill. I added a light and I covered the belts since I was getting chips in between the belt and pulley.
\nI have been asked what my travel is so I measured it. I have 4.1 inches “Y” travel, 12 inches “X” travel and about 6″ “Z” travel. I could get another 1\/2 inch on the “Y” if I removed my rubber cover that keeps chips out of the ways. So far I have not needed it.<\/p>\n

Update 02-14-14:
\nI added thrust washers between the lash nuts and the table which was an awesome upgrade recommended from someone reading my page.\u00a0\u00a0 Thanks Blaine!\u00a0 My backlash on the X & Y is now 0.001 inch max.\u00a0\u00a0\u00a0 Make sure and pack them with some lithium grease or equivalent bearing grease.
\nMcMaster part numbers:
\n5909K31
\n5909K44
\n5909K46
\n5909K33
\nThese cover the X, Y, and Z axis.\u00a0 I did not install them on my Z axis since I have a very tight Z and did not need them.<\/p>\n

\"Thrust<\/a>
Thrust Washer<\/figcaption><\/figure>\n
\"Installed<\/a>
Installed Thrust Washer<\/figcaption><\/figure>\n","protected":false},"excerpt":{"rendered":"

I currently have many tools in my shop.\u00a0 My favorite one is the CNC mill I built from an old 1954 Benchmaster mill.\u00a0 It’s heavy […]<\/a><\/p>\n<\/div>","protected":false},"author":1,"featured_media":185,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[3],"tags":[],"class_list":["post-180","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-cnc-metal-shop"],"_links":{"self":[{"href":"https:\/\/www.freemansgarage.com\/index.php\/wp-json\/wp\/v2\/posts\/180","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.freemansgarage.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.freemansgarage.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.freemansgarage.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.freemansgarage.com\/index.php\/wp-json\/wp\/v2\/comments?post=180"}],"version-history":[{"count":4,"href":"https:\/\/www.freemansgarage.com\/index.php\/wp-json\/wp\/v2\/posts\/180\/revisions"}],"predecessor-version":[{"id":1495,"href":"https:\/\/www.freemansgarage.com\/index.php\/wp-json\/wp\/v2\/posts\/180\/revisions\/1495"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.freemansgarage.com\/index.php\/wp-json\/wp\/v2\/media\/185"}],"wp:attachment":[{"href":"https:\/\/www.freemansgarage.com\/index.php\/wp-json\/wp\/v2\/media?parent=180"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.freemansgarage.com\/index.php\/wp-json\/wp\/v2\/categories?post=180"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.freemansgarage.com\/index.php\/wp-json\/wp\/v2\/tags?post=180"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}