Milling Machines

  1. Cincinnati Cinova 80
  2. Grizzly G3617
  3. Cincinnati 12 inch B. G. Plain

King Ghidora
Cincinnati Cinova 80 205-12

In December 2011 I found a milling machine that appeared to be exactly what I had been looking for: A Cincinnati universal milling machine (swiveling table) with independent overarm spindle and a lead attachment for a dividing head. The DRO was a bonus. I drove to Industrial Surplus in Connecticut to see it in person. I liked the machine and I liked the staff, so I bought it. During the inspection, we noticed a minor problem with the table feed, but they fixed that sent me a video to show that it was working before we completed the sale.

Once I received the machine (on a cold January morning), I discovered that a previous owner had rewired it for 480V. My shop has 240V 3Ø power, so I had to rewire the motors and change the heaters in the main motor starter (the overarm motor heaters were still the original ones for 240V current). I also discovered that the lead attachment did not align with the drive on my 10" Cincinnati Dividing head. I solved that problem by making a new housing for the drive gear from a cast iron disc.

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Horizontal Milling a Slot
 

I have a variety of accessories for this machine. The lead attachment only had one set of change gears, but I found a full set on eBay. The 10" Cincinnati dividing head mentioned earlier was missing a number of pieces; however, in December 2013 I was visiting Hamilton Tools in Beaver Falls PA (one of my favorite stores) and found another Cincinnati with all the pieces - including a 10-inch chuck - still packed in cosmoline, at a very fair price. I bought it. I bought a 4-jaw chuck and machined a backing plate to fit the chuck to the threaded spindle. At some time, I plan to make an ER-40 collet adapter for the fit the B&S spindle taper. Other accessories for the mill include various plain, swivel, and tilting vises; 10" plain, 16" plain, and 8" tilting rotary tables; an 8" super spacer; and a Troyke DMT-12 rotary cross slide table. I also have an assortment of tooling including end mills, face mills, shell mills, various Morse taper adapters, two Chandler Duplex boring heads, a Criterion boring head (and a clone), and a drill chuck.

 

The last project that I had before moving out of Illinois was to drill some holes in stainless steel kettles for a friend who was making a beer brewing setup. The the flexibility of the universal head on the overarm made setup easy, and the rigidity of the mill eliminated the problem of the drill bit grabbing and tearing the kettle. Just to be careful, I drilled the holes undersize and used a tapered end mill to enlarge them to finished diameter (alas, no photo!). Note the board to keep the kettle from shifting..

Setup Close-up
 

What I like

  • The universal table coupled with the lead attachment for driving a dividing head allows helical milling.
  • The independent overarm spindle with universal head provides considerable flexibility.
  • The mill is rigid and powerful enough for my needs.

What I dislike

  • I did not like the electrical interlocks, so I reprogrammed them to suit my needs. In particular, the table feed clutch solenoid could not engage unless one of the spindles was running. I changed this so that I could use the rapid feed during work setup.

Problems (this was a used machine)

  • A previous owner rewired this mill for 480V, so I had to convert it back to 240V.
  • The stop button for the independent overarm spindle was lost in the original machine shipment to my house, so I had to make a new one.
  • The arbor support oil fill plug was missing.

Other comments

  • I have not filled and operated the coolant system

King Ghidora is a three-headed monster. This mill has the horizontal spindle, the independent overarm spindle, and the dividing head spindle.


Megalon
Grizzly G3617

 
 

My first large machine was a Grizzly G3617 horizontal/vertical milling machine. Having both a horizontal spindle and a vertical spindle in one machine gives me a lot of capability in a small package that weighs little more than a ton. Yes, I would like to have a large Bridgeport vertical mill, but that lies in the future.

I modified my G3617 by adding a three-axis DRO with four scales, using an A-B box to select whether the z-axis reads knee or quill movement.

A dividing head, rotary table, and rotary cross slide table are essential accessories. I use the rotary and rotary cross slide tables for making caving equipment. I've used the dividing head for model work and for gear cutting.

What I like

  • Having both vertical and horizontal spindles on my first mill.
  • I machine a lot of aluminum, and flood coolant greatly reduces aluminum buildup on the cutting tool.
  • The DRO is almost an essential accessory for a milling machine.

What I dislike

  • The vertical spindle to table distance is only 17 inches, and I often find the need for more (especially when using long drills or the Troyke rotary cross-slide table).
  • Changing vertical spindle speeds requires manipulating belts in a confined area, so the task is neither convenient nor particularly rapid. At least I was able to mill slots in the cover so that I could remove them without having to completely remove the retaining screws.
  • The horizontal arbor is not keyed. This protects the small R8 spindle, but limits one to light cuts.

Problems (this was a new machine)

  • The starting capacitor on the horizontal spindle motor was defective. Grizzly provided a free replacement under warranty.
  • The vertical spindle drawbar stripped its threads after about two years. I replaced it with an Enco drawbar.
  • After years of use, a loose connection on the vertical spindle motor terminal box overheated and destroyed the terminal block, so I needed to buy a replacement.

Other comments

  • I modified the coolant system and replaced the factory nozzle with a manifold block of my own design, and added appropriate nozzles

Megalon has two rotating arms that superficially resemble milling cutters (or rock drills). This mill has two spindles.


Anguiras
Cincinnati 18 inch B. G. Plain

In the fall of 2008, I saw an older Cincinnati Mill for sale, and I opened the bidding at $100, not seriously expecting to win. No one else bid, so I ended up driving to Hartford and brought this machine back in my Brother-in-law's pickup. A week later, I found a Brown & Sharpe #24 vise on eBay. It was only a few miles from home, and I was able to retrieve it the next day. Finally, I added a flood coolant system. I mill a lot of aluminum, and flooding the work with soluble cutting oil keeps aluminum from building up on the cutters.

The 5-horse motor makes this machine look rather top-heavy, but closer inspection shows that the motor replaced the original line-shaft drive. The mill is old, and still uses the old B&S #10 taper that the NMTB superceded in 1927.I could not find a model number or date of manufacture on the machine, but I found a picture and description of a remarkably similar yet smaller (12") mill in A Treatise on Milling and Milling Machines, The Cincinnati Milling Machine Company, 1916:

On the slower slow speeds, the cutter can place huge loads (several tons) on the work, so clamping the work in place is just as important when using this mill as it is when using the large shaper. I haven't had any problems with aluminum, but I've made a few mistakes when milling steel, and ruined a few jobs in the process.

Form Cutter Milling: D-8 Camlock Studs Straddle Milling: Feet for Godzilla
 

What I like

  • The table feed and stop dog arrangement works well for repetitive work.
  • The front supports lock the overarm and table together, giving good rigidity.

What I dislike

  • Because of the front support, adjusting the table height takes a long time.
  • The B&S spindle taper is no longer a standard, having been replaced in 1927 by the NMTB standard, so replacement arbor are not available.
  • Changing speeds and feeds requires changing the gearing. This is slow.

Problems

  • There was considerable backlash in the gearing that caused the hand wheel to jump on heavy cuts. I removed the hand wheel and installed a 0.018" shim between the wheel and the gear housing to address this issue.

Other comments

  • The cutting forces are huge. When clamping work directly to the table, it is easy to underestimate how many claps are needed. I have not had problems with the vise slipping.

Anguiras is an old monster that appeared in the second Godzilla film.


Done