Bridgeport 101

Drilling is vertical cutting only

Milling is vertical and side cutting, at least three axis action

The Bridgeport knee mill is one of the most famous and widely distributed of all machine tools in the era of modern machining

Safety

• Don't wear gloves
• Don't wear long sleeves or 'dangly' clothing
• Retire bracelets, rings and watches to your pocket
• Restrain long hair and bad ass beards
• Wear eye protection
• Wear closed shoes (no sandals, crocs, etc) Steel toe isn't a bad idea.
• Don't operate while impaired by drugs, alcohol, sleepiness, hunger, or need to relieve yourself
• Be sure the work piece is securely fixtured

What to do WHEN�something breaks

• Shut everything down as soon as possible
• Leave a sign on the machine that it is out of order
• Report the breakage
• Use Talk Forum of the DallasMakerSpace Website, machine shop to report breakage, missing essentials, or even that the machine vibrates or sounds unusual.
• If the machine is out of order or its utility is notably degraded, report the situation by updating the tool status page on WIKI so that a long range commuter doesn't get surprised.

What to do WHEN�something breaks

• Shut everything down as soon as possible
• Place a sign on the mill that says what the issue is
• Report the breakage on talk forum
• https://dallasmakerspace.org/wiki/Machine_Shop_Tasks
• Supplies/Replacement tooling
• Maintenance
• Email:machineshop@dallasmakerspace.org

Reporting Problems by the Talk Forum

Report breakage and

problems using the

DMS Talk Forum

accessed by the

DMS homepage

Noise

• Metalworking when done properly is MUCH quieter then woodworking.
• If it doesn't sound right, then STOP
• The most common cause of noise, excessive vibration is that the work piece is not adequately supported and is subject deflection. Uncorrected, this will usually result in poor finish quality and dimensional errors.

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Basic Rules

• Clean up your mess!
• Use vacuum, not compressed air to clean up chips (blowing is an eye hazard)
• Put the tools back where they belong!
• Put the vice back on the bed, if you don't have time to square it, leave obviously un squared, at an angle!
• Don't put broken tools back
• Report breakage that would impede the next member's usage
• If you don't know, ask!

For more information

• User manual from //Files/committees/machineshop/Training/bridgeport
• Wiki Page
• For now slide show is at Committees(N:)//machineshop/training/BKBridgeport101class
• If you’re going to use the mill, take the time to review this document!
• Watch MIT Machine Shop Videos on YouTube for really good,basic instruction using the Bridgeport mill.
• For cutting speed and feeds, refer to the space's copy of the machinery handbook.
• Provides current speeds as surface feet per minute (SFM). To get RPM

RPM = SFM * 4 / Diameter of cutting tool (inches)

• Tables provide maximum, start at about 2/3 of provided value

For more information

• https://dallasmakerspace.org/wiki/Machine_Shop_Committee#External_Sites
• machineshop@dallasmakerspace.org
• Spend the time to watch the MIT manual lathe videos (4, 5, 6, 7 at right) if you don't have much experience with a machining
• Ask around.
• Talk Forum
• See somebody working in the machine shop

machineshop@dallasmakerspace.org

Cutting Fluids

• Use cutting fluid, liberally, when cutting anything other than brass, plastics or cast iron.
• WD 40 is widely available in the shop; some folks prefer other fluids
• Note: heat shortens the life of cutters.

Controls

• Oil the ways

Controls

Controls

• X motion control and locks

X Axis Lock

X Axis Lock

Controls

• Y motion control and locks

Y Axis Lock

Controls

• Z motion control and locks

Controls

• Quill Controls
• Motor Control
• Gearing (High / Low)�Only when off
• Brake
• Speed Control�Only when on

DRO

• Avoids backlash
• On X, Y and Z coordinates
• Shut off when not using
• Always use when the work is dimensionally exacting

Power feed

• Make sure x-axis IS NOT LOCKED
• Make sure vise and Z-axis handle will not conflict
• If you hear a grinding noise, STOP

Getting Started

• Give the oiler chamber handle one pull
• Check if Vice is square, using dial gauge if accuracy is needed.
• Consider how the piece is to be fixtured; if it moves during the cutting, it will likely be ruined
• Assemble the measuring tools and fixturing hardware needed. And the cutting fluid.
• Check that the quill is all the way up and locked before loading any tool in the spindle. Also, necessary for unloading.
• Check that the X,Y and Z are unlocked, especially the X before using the power feed!

Milling Vice and Dial indicator

• Run indicator across vice jaw (or back) to ensure vice is square

TRAM

• Tram concerns - How square is the Mill Spindle to the bed of the mill?
• Don't mess with the tram. It is difficult to restore and you don't want to be responsible for restoring it unless you have the expertise and time.
• Use the tilt table instead to perform angle milling
• Tram out of true will result in compromised milling especially when using the Face Mill

Measurement Tools

• Scales (rulers)
• Combination Square
• Calipers
• Micrometers
• Dial Indicators

Scales

Combination Square

Calipers

• Measures to 6”/150mm
• Accurate to a few 0.001”/01mm

Micrometers

• Small range
• Accurate to a few 0.0001”
• Takes�practice�to achieve�accuracy

Dial Indicators

• Can be used�to measure�Z-axis travel
• Typically 1”�range, with�0.001” precision

R8 Collet

Only load milling cutters in a collet. While drill bits can be loaded in a collet, don't ever load milling cutters in a drill chuck, they can not support lateral loading.

End mills

• Know if your end mill is center cutting and why. End mills not configured for center cutting can only be used to plunge if a center hole has already been drilled.
• Come in a wide variety of styles such as: flat ends, ball ends, corner cutters, V cutters, T cutters
• 2/3 flute for aluminum, 4 flute for steel or cast iron

Face Mill

• Used for surfacing the top of a workpiece
• Can't get into corners typically

Holding Parts

• Vice is most versatile, especially with parallels
• Thin parts require special treatment
• Can use clamping set on bed

Locating Parts

• Need to determine origin point
• Center finder for holes
• Edge finder for parts

• Use edge finder to find origin per plan, Note: edge finding cylinder has 200 mill diameter.
• No plans, you still have to decide on an origin point

Post Operations

• Deburring
• Cleaning

Cleaning The Part

• Torrent Parts Washer
• Parts can change size after initial milling

Mill Side

Proceed to mill