13 August 2019
13 August 2019,

R8 tool holder or Morse taper? The debate into which is better has been going on for years. If you know this blog, you know we think the R8 is better than the Morse taper.  When Bridgeport created the R8 tool holder method, they changed machining forever and paved the way for modern CNC machining. And in the scheme of things, it wasn’t that long ago.

In the Beginning

To get to the start of the R8 tool holder, you must get to the start of the Bridgeport Machine Company. That starts with Rudolph Bannow. Rudolph was a Swedish immigrant. He started his career as a pattern maker and eventually worked his way up to foreman at the Bridgeport Pattern and Model Works in Bridgeport Connecticut. In 1927, he bought the company. Under his leadership, the focus shifted to production of a versatile milling attachment. This head mounted on a number of different machines.

Bannow brought in Magnus Wahlstrom as a partner in 1929. They went to work on an idea for a hedge clipper powered by an electric motor. While it was a great idea, it was a bit ahead of its time. The 20’s saw the invention of the electric hair clipper, but the world wasn’t ready for an electric hedge clipper.

So, they shifted focus to a vertical milling attachment that could be added to many horizontal milling machines. Their “Master Milling Attachment” had a 1/4 hp motor and could run at 6 set speeds from 465 to 4250 rpm. The first unit was delivered to the Atlas Tool Company right in Bridgeport.

Bridgeport with R8 tool holderFrom Attachment to Mill – the R8 Tool Holder is Born

Legend has it that one day Rudolph Bannow was delivering one of their Master Milling Attachments to a customer and had a bit of a wait. By this time, they had vastly improved on their original design and were selling about 500 units per year. The year is 1938.  Bannow had some time to kill and he passed it sketching on a paper bag. The idea? Their very own milling machine that incorporated all the features of their Master Milling Attachment and more.

The company name changed to Bridgeport Machine, Inc. and the first unit was delivered in August of 1938. The Precision Die Casting Company in Syracuse paid the princely sum of $995 for the first unit. It’s on display today at The Precision Museum in Windsor, Vermont.

The entire upper turret pivoted. The horizontal ram moved up to a foot forwards and backwards. The head assembly swung right or left and tilted. The design captured the hearts of machinists worldwide.

By moving the motor to the side, they made plenty of room for a drawbar to tighten the tool holder in place. Machinists now insert tools directly in the spindle. Furthermore, the collets are keyed and tightened with a collet wrench.

r8 tool holder protects colletsMaking Tool Holders for the R8 Tool Holder

Sierra American Multi-Systems hopes you enjoyed this bit of history on the R8 tool holder. We love the R8 tool holder so much we created trays to keep your R8 collets safe.

If you love the R8 as much as we do, protect your collets with an R8 tool holder from Sierra American. Find it where CNC supplies are sold.

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