Hitch Pins, R Pins & Hair Pin Clips

Hitch pins, R pins and hair pin clips

Hobson publishes no load rating, working load or capacity for any pin or clip on this page. That is why we do not offer them for tow hitches, towbar receivers, trailer couplings or anything holding a load over people: those need a pin rated for the job by the vehicle, trailer or equipment maker, or an engineer's specification.

• •Hitch pin with linch pin: a pin with a handle and collar at one end and a cross hole at the other. The linch pin goes through the cross hole and, per Hobson, stops the hitch pin accidentally sliding out. Hobson's drawing shows the linch pin tethered to the handle by a chain. Hobson publishes no rating for them, so they are not for tow hitches, drawbars, trailer or implement couplings, three-point linkages or any pin that joins a towed or towing machine; use the pin the machine or trailer maker specifies.
• •Double coil R pin (R clip): a spring wire clip. Its straight leg goes through a cross hole in a clevis pin, bolt or axle and its curved leg clips over the shaft. Hobson lists them for securing clevis pins, bolts and axles; the double coil lets you attach a tether cable so the clip is not lost, and it can be reused.
• •Hair pin retainer clip: a spring clip that retains grooved pins. Hobson lists it as reusable and easy to fit, with each size suiting a range of pin diameters.

Hitch pin sizes

Hitch pins are sold in inches as pin diameter x length. The pin has to slide through the holes it joins, and its length (C on Hobson's drawing, from under the collar to the linch pin hole) has to clear everything it passes through. Select a row to open that pin in the selector.

R pin sizes: hole and shaft

Pick an R pin by two numbers: the cross hole it goes through (its size, 2 to 8mm) and the diameter of the shaft it clips over. A 4mm R pin suits a 4mm hole in a shaft of 16 to 25mm. Single coil R clips (humpback pins) from 1.2 to 7.9mm are on the split pin page.

Hair pin clip sizes

Hobson lists the hair pin clip sizes as 3, 5, 8 and 11 and gives the clip dimensions below, but no pin diameter range for each size. Check the clip against the pin and its groove, or ask us.

Zinc yellow and zinc plated: where they last

Hobson's coatings chart puts both at about 5μm of zinc. Zinc plated (the R pins and hair pin clips) is for indoor and non-corrosive environments. Zinc yellow passivate (the hitch pins) has more corrosion resistance than plain zinc but is still recommended for low-corrosion environments or temporary fixing.

Hobson's corrosion guide for metal connectors calls for stainless steel or hot dip galvanising for anything exposed to weather and rain. On gear that lives outside, check pins and clips for rust and replace them; for stainless, see the 316 stainless linch pins and 304 stainless locking pins on the locking pin page.

Fitting hitch pins and R pins

1. Line up the holes and push the hitch pin through until the collar sits against the part.
2. Fit the linch pin through the cross hole in the end of the hitch pin.
3. For an R pin, push the straight leg through the cross hole in the clevis pin or shaft until the curved leg clips over the shaft.
4. Tether the R pin through its double coil where losing it would let a pin fall out.
5. Check pins and clips before use and replace any that are bent, cracked, rusted or no longer spring tight.

Hitch pins and clips in Adelaide

Allmat supplies hitch pins, R pins, hair pin clips, split pins and linch pins to farmers, contractors, mechanics and trade across Adelaide and South Australia. Add them to a quote with the rest of your list, and we will price the lot.

Questions