Enco RF-30 Mill

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Hive13 Equipment
List of All Documented Equipment
Owner/Loaner: User:Paul
Hive13 Asset Tag: HV0039
Make/Model: Enco 105-1110 (google)
Arrival Date: 03/2012
Does it work?: Yes
Certification Needed?: Yes
Contact: CNC Warden
Floorplan: Machining
Manual: Manual


Paul purchased this mill from an auction for $625. It was owned and operated by a retired electrical engineer who worked at a machine shop, prior history is unknown.

It has a travel of 185mm forward and back, 430mm left to right, and 130mm on the spindle. (7.25" x 16.875" x 5.125")

The collet taper is R8.

User Certification

We do Mill and Lathe certification on an as needed basis. Email the warden to request certification. Only the following people are permitted to certify you on the mill:

  • Paul (Project Leader - mill owner)
  • Kevin McLeod
  • Brad
  • Dave Velzy

Certification Goals – Don’t hurt yourself. Don’t hurt the machine.

  • Mill safety and setup
  • Tool selection for milling operations
  • Holding parts using the machinist vice and parallels
  • Change tools and set spindle speeds
  • “Zero” the X, Y and Z axis using the DRO
  • Perform basic facing cuts on steel
  • Mount and secure work using parallels and hold downs
  • Demonstrate understanding of Backlash

In preparation for certification please; Read the manufacturers manual and study the excellent materials from Case Western


Take the milling quiz.

https://www.proprofs.com/quiz-school/story.php?title=mill-quiz When you have a score of 100% print out the certificate and contact the CNC warden for your certification check ride.

Current Status

The ENCO Mill works well. Take care to clean and lightly oil it each time you use it.

A defect was identified with the Pinion Assembly (enco part number 6116-6S) via borescope on 2/22/2015. Ian and Ryan identified the busticated part.

Ian emailed Jon on 2/22/15 asking if he wanted to get the part, or, if he wants me to buy the replacement part. Ian's going to give Jon until the 24th to reply before ordering the replacement part and getting it to the hive to be installed.

After further digging it looks like this is a hard to get part. MSCdirect can order it from overseas (MSC# 04872396) $134.03 with a 12-15 week lead-time. [1]

Jon found the complete spindle assembly from Enco (505-7373) for around $200 with a 12-15 week lead time. This includes new bearings, which probably would need replacement anyway.

Some forum digging found that if it is just the anti-rotation pin that is damaged, it can be removed/replaced. The pin is used for collet registration (presents the same face of the collet each time) and anti-rotation (for when you tighten the drawbar). Many people talk about having removed the pin for many years. The true anti-rotation for the collet in operation comes from the R8 taper being compressed by the drawbar.

Obtained a new drawbar from MSCdirect to replace the one that was destroyed.

I cleaned the unit up and tightened the gibs on the X and Y tables. It seems to be working much better now.

Mounted the DRO550 and one iGaging scale to the Z axis (spindle vertical travel). Checked the travel with a set of 1-2-3 blocks and the DRO is right on the money. Interestingly the manual "fine adjustment" on the mill is off. If I zero the spindle at almost fully retracted against the 3" and 2" blocks, then drop in 1" increments

123 blocks 0.000 1.000 2.000 3.000 4.000
DRO 0.000 1.000 2.000 3.000 4.000
Fine Adj 0.000 1.012 2.013 3.036 4.048

For short travel the fine adjustment is probably OK, but over longer travel it is off by up to 1.2%

Still need to mount the DRO display, maybe put it on an arm for a monitor?

Installed the new R8 spindle from Enco. The installation went well (now we have the internal keyway back) but unfortunately the return spring for the spindle broke when I tried to reinstall it. I have ordered a replacement from Enco. The mill is functional but the spindle tends to drift downward if you don't lock it, hence the need for the return spring :).

Received the new return spring from Enco and installed it. The mill is now functional!

Next steps are to install the X and Y scales that were loaned by Dave Lear.

Began fabrication of mounts for X scale. During the fabrication I noticed that the Z digital readout would "skip" to a different number (like off by .500"). Not sure if it is from noise or cables. Chased down the fault and it looks like it occurs randomly when the mill is shutdown. Probably due to a power spike from the motor/switch and the cheap power supply for the DRO. Some digging on the forums revealed that others have seen this jump. Some people just went to battery power to avoid any issue.

Installed the X and Y scales on the mill. Everything seems to be working but I would like to verify the X and Y axis with the 123 blocks. I should be able to do this during the holiday break.

I bought a 8 AA battery holder that could feed power to the DRO, totally isolating it.

The 8 AA battery holder plugged right into the DRO and everything seems to be working great. No more skipping as the mill is turned on or off. I'm pretty sure the batteries will last many months. The holder has an on-off switch so I left it "off".

Checked the X and Y calibration with the 123 blocks and everything is right on the money. I had to correct the CPI (Counts per Inch) setting on the DRO. For some reason they were incorrect.

I would also like to print out the DRO software manual and mount it by the DRO to help people use it.

Installed a simple sheet metal guard for the X axis scale. It should protect the scale from chips and damage. I might make a more sturdy version later.

The DRO is working but there is a peculiar jumping that happens when their is a drop in power to the DRO. The axis can skip up or down .200" semi-randomly. This appears to be due to the internal circuitry not handling the loss of power. Lorin suggested adding some capacitors to the power infeed to smooth out the system.

Did some testing of the z drift as the tables are traversed (basically I mounted an accurate indicator on the spindle and touched the table, zeroed out the indicator and then traversed the table).

Removed the top of the mill vise and indicated along the Y direction (away from the operator). All numbers are in inches.

0 .5 1 1.5 2 2.5 3 3.5 4 4.5
0.000 0.000 0.000 0.000 0.000 0.00025 0.00025 0.00025 0.00025 0.00025

The 0.00025" is a rough measurement on the indicator. You can just make out .00025" and the value slowly walks up to a solid 0.00025" at 4.5". So the Y table is pretty flat!

The X axis is much longer. I placed an accurate parallel in the vise and measured across it from the left side to the right.

0 .5 1.5 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6
0 0 0.00025- 0.00025 0.0005- 0.0005 0.00075 0.001 0.00125 0.0015 0.00175 0.002 0.00225

So the X axis is a bit worse than the Y. Looks like about 6 times worse than the Y (0.0015" vs 0.00025"). Still only about .002" over 6" is not that bad. Just have to take that into account if you make anything long in the X. We can work on shimming the vise to get the X plane perpendicular to the spindle axis.

Ran the test indicator just on the table (not on parallels in the vise). Got much better results.

0 .5 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5 10
0 0 0 0 0 0.00025 0.0005 0.0005 0.00075- 0.00075 0.00075+ 0.00075 0.001- 0.001- 0.001 0.001+ 0.001+ 0.00125- 0.00125 0.00125

So it looks like the vise needs to be shimmed to get the X plane more parallel to the table.

While trying to mill a small Aluminum part I was able to confirm that the vise will "lift" a part if the load on the vise is near the top of the vise jaws. Basically the load needs to be at least half way down the vise jaws (the lower the better). Otherwise the moveable jaw of the vise pivots back and lifts that side of the part. There are some discussions on the web about using a drill rod to roll up the part as the vise jaw shifts but I haven't found that to work very well. Just keep it in mind if you are trying to get parallel sides on a part.


  • Figure out the tool maintenance requirements to keep it running.
  • Do some cable routing for the scale readers. Especially the Y axis since on that one the reader moves with the table.
  • DRO still skips periodically, be nice to try adding the capacitors that Lorin suggested to see if that helps.

Historic Info

Switch Replacement

The power switch failed and was replaced with one that matched the rated motor amps. The new switch frame an contacts were much larger than the original. The internal switch wiring was also different.

The New Switch

File:Enco Mill Switch Replacement 2021.08.24.pdf This diagrams the switch wiring.

Rack Replacement

The rack is the linear gear that helps the operator easily raise and lower the head of the Mill. See the Wikipedia article for more information. Looks like some parts might be available for purchase directly from Enco if we contact their parts number or email them directly. More information on: http://www.use-enco.com/cgi/inpage?pmpage=machinery/manuals.htm

The important quote from that page:

NOTE: Machinery parts are NOT available online. Please contact our Technical and Parts Representatives at 1-800-USE-ENCO or email your inquiry to encotechandparts@use-enco.com. Our representatives are available Monday - Friday, 8am-8pm Eastern Time.
—Enco Repo, Enco Page

Update: Rack was indeed available from Enco, purchased for $72 (shipping included). Rack was installed by Paul & his father.


The endmills are the cutting tools for the milling machine. Wikipedia has a page for these as well.

Hive owns a variety of high speed steel end mills which were purchased used on eBay. They are under the mill labeled 'Good enough'

If you damage one, report it to broken (at) hive13 dot org

WTB (Want to Buy)

  • Toolbox // Tool Chest to hold machining parts
  • Rotary Table (8"+), one that can be used vertically & horizontally ($100 - $300+)
  • Boring head + Boring bar set
    • Boring head ~$75
    • Boring bar set ~($20 - $60)

Priority Purchase List

  • Way Oil (Vactra #2)-- [2]
  • 1"x2" 6061 Aluminum (Soft Jaw material) [3]

Sites to buy from for cheap


Milled Items

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iGaging scale on Z axis of mill


Manuals & Guides


Supplies & Parts

General Information