The following may help you navigate the most common mechanical parts we use from the lab supply.
Note: the McMaster-Carr purchasing links frequently include downloadable CAD models to import into SolidWorks.
Clevis Pins, 1/4 Inch
Clevis pins may be used as pivots, shafts, and locking pins. They feature a flanged head at one end and at the other a cross-hole through which a cotter pin may be inserted for retention. These are commonly found in low-speed joints which don’t require speed or precision.
Description: clevis pin, 1/4” diameter, 1/2” nominal length, 5/16” usable length
Location: Hardware Drawer 13
Part Number: 2442
Description: clevis pin, 1/4” diameter, 1” nominal length, 13/16” usable length
Location: Hardware Drawer 13
Part Number: 2444
Description: clevis pin, 1/4” diameter, 2” nominal length, 1-13/16” usable length
Location: Hardware Drawer 13
Part Number: 2446
Description: clevis pin, 1/4” diameter, 3” nominal length, 2-13/16” usable length
Location: Hardware Drawer 13
Part Number: 2448
Description: cotter pin, hairpin shape, to secure 1/4” clevis pin, 3/64” wire diameter
Location: Hardware Drawer 13
Part Number: 2450
Shoulder Screws, 1/4 Inch
Shoulders screws have a smooth precision-ground section and a threaded end with a smaller diameter. These are intended as rotational shafts to use with either either the bushing bearings or ball bearings. The shoulder is 0.250 inch diameter, the thread is 10-24, and the head is a 1/8 inch hex socket. They will rust if wet.
Description: shoulder screw, 1/4” diameter x 1” length shoulder, 10-24 threaded end, alloy steel, used as axle
Location: SHELF-B-5 : Shoulder screws, bearings, & bushings kit
Part Number: 1554
Description: shoulder screw, 1/4” diameter x 1-1/2” length shoulder, 10-24 threaded end, alloy steel, used as axle
Location: SHELF-B-5 : Shoulder screws, bearings, & bushings kit
Part Number: 1548
Description: hex nut, #10-24, zinc plated, for shoulder screws
Location: SHELF-B-5 : Shoulder screws, bearings, & bushings kit
Part Number: 1588
These #10-24 hex nuts fit the threaded end of the shoulder screws. The nominal width is 3/8 inch.
Description: washer, for #10 hardware, zinc yellow chromate plated steel, 1/2” outer diameter x 0.220” inner diameter
Location: SHELF-B-5 : Washers Kit
Part Number: 1610
These washers fit over the threaded end of the shoulder screw but not the shoulder.
Description: spacer, nylon, unthreaded, 1/2” outer diameter, 1/4” length, for 1/4” screw size, off-white
Part Number: 6047
These spacers are especially suitable to adjust the effective length of shoulder screws, but may also be used as thick washers.
Description: washer, for 1/4” hardware, zinc chromate plated steel, 0.734” outer diameter x 0.312” inner diameter
Location: SHELF-B-5 : Washers Kit
Part Number: 1608
These washers fit over the shoulder section of shoulder screw.
Description: shaft collar, for 1/4” shaft, one-piece clamp-on
Location: SHELF-B-5 : Shafts, collars, & couplers kit
Part Number: 1542
Clamp-on collars can be used as high-load axial constraints on shoulder screws or plain shafts.
Description: shaft collar, for 1/4” shaft, set screw type
Location: SHELF-B-5 : Shafts, collars, & couplers kit
Part Number: 1552
Set-screw collar can be used as light-duty axial constraints on shoulder screws or plain shafts.
Bushing Bearings
Bushings are robust bearings with reasonable precision and low friction. They are made of a low-friction material on which steel shafts can easily rotate or slide. Bushings can be directly pressed into laser-cut holes.
Description: bushing bearing, for 1/4” shaft, SAE 863 Bronze, 5/16” OD, 1/4” Length
Location: SHELF-B-5 : Shoulder screws, bearings, & bushings kit
Part Number: 1570
The bushing has a nominal outside diameter of 8.0 mm; a hole drawn as 7.8 mm in laser-cut 6 mm plywood will yield a snug press-fit.
Description: bushing, for 1/4” shaft, flanged, SAE 863 Bronze, 3/8” outer diameter x 1/4” length x 1/2” flange outer diameter
Location: SHELF-B-5 : Shoulder screws, bearings, & bushings kit
Part Number: 1562
Ball Bearings
Ball bearings are more precise than bushings and can handle higher loads and speeds. They are generally used in pairs, spaced as widely as possible, typically with a shoulder screw used as a shaft.
Description: ball bearing, for 1/4” shaft, 3/8” outer diameter, shielded, flanged
Location: SHELF-B-5 : Shoulder screws, bearings, & bushings kit
Part Number: 1584
These are made small and thin by using small light-duty bearing balls.
Description: ball bearing, for 1/4” shaft diameter, 5/8” outside diameter, shielded
Location: SHELF-B-5 : Shoulder screws, bearings, & bushings kit
Part Number: 1534
Description: ball bearing, for 1/4” shaft, 3/4” outside diameter, shielded
Location: SHELF-B-5 : Shoulder screws, bearings, & bushings kit
Part Number: 1550
Note that these have both a larger diameter and thickness.
Dowel Pins
Dowel pins come in wood, plastic, or metal. Wood pins are typically used to connect wooden parts. Plastic and metal are typically used as pivots or to precisely locate parts.
Description: wooden dowel, 1/4” outer diameter, 1-1/2” length, fluted, chamfered ends
Location: Hardware Drawer 13
Part Number: 1573
The pin has a nominal outside diameter of 6.4 mm; a hole drawn as 6.0 mm in laser-cut 6 mm plywood will yield a tight hammer-in press-fit.
Description: wooden dowel, 5/16” outer diameter, 1-1/2” length, fluted, chamfered ends
Location: Hardware Drawer 13
Part Number: 1575
Description: wooden dowel, 3/8” outer diameter, 1-1/2” length, fluted, chamfered ends
Location: Hardware Drawer 13
Part Number: 1577
M3 Metric Fasteners
Description: screw, M3 x 6mm length, socket cap, button head, 18-8 stainless
Location: SHELF-B-6 : M3 Kit
Part Number: 1832
Description: bolt, M3 x 10mm length, button head, stainless steel
Location: Hardware Drawer 8
Part Number: 1829
These are a good length for mounting a NEMA17 stepper motor onto a 6mm panel.
Description: bolt, M3 x 20mm length, button head, stainless steel
Location: Hardware Drawer 8
Part Number: 1828
Description: bolt, M3 x 30mm length, button head, stainless steel
Location: Hardware Drawer 8
Part Number: 1826
Description: screw, M3 x 40mm length, socket cap, button head, 18-8 stainless
Location: SHELF-B-6 : M3 Kit
Part Number: 1822
Description: bolt, M3 x 50mm length, button head, black-oxide alloy steel
Location: SHELF-B-6 : M3 Kit
Part Number: 1820
Description: M3 x 16 screw, plastic, slotted cheese-head
Part Number: 6051
Plastic screws are frequently used to mount electronics. These fit through the Arduino mounting holes.
Description: washer, M3, 18-8 stainless steel, 7mm outer diameter x 3.2mm inner diameter
Location: SHELF-B-6 : M3 Kit
Part Number: 1836
Description: nut, M3 x 0.5mm pitch, 5.5mm width, 2.4mm height, zinc plated steel
Location: Hardware Drawer 8
Part Number: 1838
Description: threaded insert, M3, screw-to-expand, uses 5/32” drill hole
Location: M3 Kit
Part Number: 1825
These inserts can be pressed into a 4.0 mm wood or plastic hole to provide a precision M3 threaded hole.
Description: spacer, nylon, for M3 screws, 3.3mm inner diameter x 4mm length
Part Number: 6053
Motors and Actuators
Description: small hobby servo, 4.8–6V, no-load speed 60º in 0.12 seconds, stall torque 1.2–1.4kg×cm, 9g mass, clear blue, SG90
Location: Motor and Mechanism 4
Part Number: 1896
Description: hobby servo motor, large, metal output spline, LKY62
Location: Motor and Mechanism 4
Part Number: 1899
Description: gearmotor, brushed DC motor, 6V, 4mm diameter x 25mm length shaft, no load 130rpm drawing 100mA, 1kg*cm load 100pm drawing 0.45A, stall at 3.6kg*cm drawing 1.8A
Location: Motor and Mechanism 4
Part Number: 1931
We have purchased slightly different variations of this motor. Some have a pair of M3 threaded mounting holes spaced 17 mm apart, some spaced 15 mm apart. The boss is 7 mm diameter.
Description: hub, for 4mm shaft, with M3 tapped holes, 2-pack
Part Number: 6049
These hubs are the only practical way to mount a load on the small gearmotors with 4 mm shafts. More details: Pololu 1997 Motor Hub Drawing, SolidWorks model.
Misc. Components
Description: spring kit, assorted compression and extension springs, 200 pieces
Location: Craft 2
Part Number: 1518
They may be useful as countersprings to provide return motion, as energy storage, or as shock mountings.
Description: marbles, ~5/8” diameter
Location: Craft 4
Part Number: 2391
Traditional glass play marbles.
Description: steel ball, 3/8” diameter
Part Number: 6055
Intended to be used as freely rolling marbles or as three-axis pivots.
Description: O-ring, oil resistant, hardness durometer 70A, Buna-N material, fractional width 1/8”, size 223
Part Number: 6059
O-rings are commonly used for creating pressure-tight seals, but are included here as high-quality elastic bands for making ball bumpers, tires, or round belts.
Page generated on 2021-11-04.
