Bridgeport Knee Mill
- 1 Description
- 2 Personal Tooling and Learning Resources
- 3 Available Equipment
- 4 Repair and Maintenance
- 5 Authorization
A recent model Knee Mill made by the Bridgeport company. This is the gold-standard small shop manual milling machine in the US. Most other mills of the same size are direct copies of the bridgeport design. This particular machine is a Series I, J-head with a mechanical variable speed drive. The machine has a power quill feed built into the head, in addition to the additional equipment listed below. This machine is capable of facing, surfacing, drilling and slotting in materials ranging from plastics to mild steel. Harder metals may be cut if special cutters and coolant are available. This machine is not equipped with CNC controls, consequently curved paths are limited to circular arcs. These can be cut on pieces that can be mounted on the 8" rotary table or approximated to a desired precision using the simple or smooth arc functions of the DRO.
Personal Tooling and Learning Resources
|Cutting bits||A set of sharp cutters you don't have to share||can be purchased from McMaster, Enco or Shars||~$50 and up|
- Tubal Cain Bridgeport mill parts, part A and part B.
- MIT milling machine videos: Machine Shop 4, Machine Shop 5, Machine Shop 6, and Machine Shop 7.
- Machine Shop Practice, Volume 2. This book is available in the lounge library and in the cabinet next to the mill.
- Machinery's Handbook. Three copies of this are available in the cabinet next to the mill.
- Milling Machine Operations. This is published by the United States Army, and is therefore in the public domain and freely available online.
- Power feed Model 8F (need to verify) (x axis)
- Digital Read Out (DRO)
- Kurt 6" vise
- Hold down set
- 5C collet set
- Palmgren 8" Rotary Table
- Boring heads
- Fly cutters
- Two flute end mills
- Tapping heads
- Tilting table
- Spindle square
- Horizontal Attachment
Repair and Maintenance
Please see the service manual.
Above the high/low/neutral speed selector, there is a plate listing how frequently oiling should occur.
The tram and nod of the head, as well as the squaring of the vice, should be checked by anyone who desires high precision. Because hackerspace, there is no guarantee when they were last adjusted.
The X-axis handle (opposite the power feed) is missing the spring.
The handle for the Z-axis front lock has snapped off. The rabbit hole is deeper than expected, or may just be a handle that can be removed.
The screw to prevent collets from rotating in the spindle is frequently removed, as some collets won't fit with it in there and it can cause bigger problems if it shears off. This won't be repaired.
The power feed appears to be leaking oil. Parts that we should consider replacing:
- 61 11636413 Seal, Shaft quantity 1
- 72 11630134 Gasket, Cover quantity 1
- 33 11630261 Bearing, Single Row, Loose Fit, quantity 2; these should be available from a bearing distributor
Good sources for Bridgeport parts: High Quality Tools, H&W Machinery Repair, Mataco
Authorization on this tool requires previous Tier 1 Cold Metals Authorization. Because of the inherent danger of using a large milling machine, authorizations on the Bridgeport Mill will only be given by members with significant experience with mills of this type. A list of members who can authorize on the Bridgeport mill may be found below.
Currently Authorized Users
|Qualified Member||Trained By||Proctored By|
|Tucker Tomlinson||Danger Committee|
|Mike Warot||Danger Committee|
|Ed Bennett||Danger Committee|
|John-Paul(JP) Debauge||Danger Committee|
|Ryan Pierce||JP Debauge||Ed Bennett|
|Everett Wilson||JP Debauge||Ryan Pierce|
|Derek Bever||JP Debauge||Everett Wilson|
|Elizabeth Koprucki||JP Debauge||Ryan Pierce, Everett Wilson|
|Anna Yu||Ed Bennett||Ed Bennett|
|Dean Anderson||Ed Bennett||Ed Bennett|
|Bart Dring||Ed Bennett||Ed Bennett|
|Greg "Nerobro" Teiber||JP Debauge||JP Debauge|
|Ray Doeksen||JP Debauge||JP Debauge|
|"Colorado" Rob Riggs||JP Debauge||Everett Wilson|
|Todd Allen||JP Debauge||Everett Wilson|
|Ron Olson||Derek Bever and Everett Wilson||Everett Wilson|
|Michael Skilton||Derek Bever and Everett Wilson||Todd Allen|
|Alan Baker||Tucker Tomlinson|
|Tom Judge||Everett Wilson||Everett Wilson|
|Ron Bean||Todd Allen||Todd Allen|
|George Shaw||Todd Allen||Todd Allen|
|Arturo Duarte||JP Debauge||Todd Allen|
|Joao Santos||Todd Allen||Dean Anderson|
|Chris Agocs||Everett Wilson||Todd / Everett|
|Lucas Goossen||Todd Allen||Todd Allen|
|Ben Bogler||Everett Wilson||Todd Allen|
|Michael Patton||Todd Allen||Todd Allen|
|David Srebro||Todd Allen||Todd Allen|
|Daniel Sojka||Todd Allen||Todd Allen & Michael Patton|
|Allen Zalsman||Todd Allen||Todd Allen|
|Justin T. Conroy||Todd Allen||Everett Wilson|
|Raj (Joseph Perera)||Everett Wilson||Everett Wilson|
|Scott Drane||JP DeBauge and Todd Allen|
|Aaron Carlock||JP Debauge||JP Debauge|
|Brandon Love||JP Debauge||JP Debauge|
List of Provisionally Authorized Users
These persons have completed the classroom portion of the authorization and have started their authorization project. They are provisionally authorized to complete their authorization project under supervision of a proctor who may be any of the authorized persons, listed above.
|Provisionally Qualified Member||Trained By|
|David Fell||Ryan Pierce and Ed Bennett|
|Michael Leinartas||Ryan Pierce and Ed Bennett|
|Sergey Nekrasov||Ryan Pierce and Ed Bennett|
|Mark Cabael||Todd Allen|