Replacement thread-mount idler rotary shafts for chain and belt tensioning.
These thread into a tapped hole on a machine, wall, or bracket and give an idler sprocket or pulley a stub to rotate on. Pick a size below to load it into the configurator, the threaded mount, seat shoulder, idler-riding body, and (on the retaining-ring style) the ring groove are pre-dimensioned. Two end styles are offered: a retaining-ring end (machined ring groove; ring and spacers included) and a shaft-collar end (adjustable collar and grease fitting included), both machined in 1215 carbon steel. You stay in control of material, surface finish, tolerance class, and any added features. The drawing's title block stamps the source SKU, and we confirm full geometry against the catalog drawing or a sample before cutting.
Flange-mount idler shafts (with an integral bolt-circle flange) and the metric thread-mount sizes aren't on these cards yet, they're on our roadmap. Need one now? Send us a print or the old shaft and we'll quote it directly.
Thread-mount idler shaft sizes
Replacement thread-mount idler rotary shafts. They thread into a tapped hole to support idler sprockets and pulleys in chain and belt tensioning. Two end styles: a retaining-ring end (machined ring groove, ring + spacers included) and a shaft-collar end (adjustable collar + grease fitting included), both machined in 1215 carbon steel. Shaft and seat diameters, thread size and length, and groove dimensions are published per size; click a card to load a configurable starting point. Crosses the McMaster 2435K / 1816K thread-mount idler series.
It threads into a tapped hole on a machine, wall, or bracket and gives an idler sprocket or pulley a stub to rotate on, used to take up slack and tension chain or belt drives. The threaded end drives into the hole; a seat shoulder sets the standoff; the idler rides on the body. Two end styles are offered: a retaining-ring end (a ring and spacers position the component) and a shaft-collar end (an adjustable collar with a grease fitting).
Match the shaft (body) diameter to your idler's bore and the thread size to your tapped mounting hole, then check the overall length and standoff. If you're replacing a catalog part, the cards cross-reference the McMaster 2435K / 1816K series. Pick the card whose cross number matches.
The difference is how the component is held at the end of the body. The retaining-ring end has a machined ring groove; a retaining ring and spacers (included) position the component. The shaft-collar end ships with an adjustable shaft collar and a grease fitting so you can set the component width and lubricate it. Both are machined in 1215 free-machining carbon steel and load into the configurator with the threaded stud and body pre-dimensioned.
Both end styles default to 1215 free-machining carbon steel at a 63 Ra turned finish, and both are configurable: switch material, finish, or tolerance class in the configurator. The McMaster parts these cross are zinc-plated (and the shaft-collar style is hardened); we machine the shaft geometry in 1215 and ship it as bare machined steel, so plating and hardening are downstream steps you would arrange separately. Material certs (MTRs) are available on request.
The shaft and seat diameters, thread size and length, overall length, and (ring-end) groove dimensions are taken from the published catalog data. The axial split, where the seat shoulder sits and the groove location, is reconstructed from the dimension table and confirmed against the catalog 2-D drawing or a sample before we cut. The drawing title block stamps the source SKU so any deviation is visible.
Not yet from these cards. Flange-mount idler shafts (with an integral bolt-circle flange) and the metric thread-mount sizes are on our roadmap. For one of those today, send us a print or the old shaft and we'll quote it directly.