THKSR35W1SSRadial-Biased LM Guide Carriage Block, Size 35 for 34 mm Rail, 48 mm Height, 90° Contact Angle, C 60.4 kN, GK Interchangeable Series, Block Only

Product Description

What this part is

This is a THK LM Guide carriage block, model SR35W — a four-row linear bearing block running on a 34 mm wide SR size-35 LM rail. The SR series differs from THK’s HSR series in one respect: the raceway geometry is arranged for a 90° contact angle rather than 45°.

The 90° contact angle

In the SR series the ball contact lines are set at 90°, which biases the block’s capacity strongly toward radial load — downward load, in a normal horizontal installation.

The published moment figures for this block are MA 0.785 kN·m and MB 0.482 kN·m. In the HSR series those two are equal, because 45° geometry is symmetrical. The SR series is built for applications where the load is predominantly downward and radial capacity per millimetre of block height is the priority. At 60.4 kN dynamic from a 48 mm tall block, the SR35W is considerably stronger radially than an HSR of comparable height.

Suited loads are mostly vertical and downward: a heavy table, a vertical machining centre saddle, a press slide. Wall-mounted, inverted or multi-direction loading is served by the HSR series, whose upward and lateral capacity is higher.

Block only

This is the block alone, with no LM rail. THK serial-number-matches standard blocks to their rails and states that “an LM rail and LM blocks used in combination must have the same serial number,” because preload and running parallelism are set as a pair.

This part carries the (GK) designation. THK’s GK series exists precisely so blocks and rails can be bought separately — the GK line “features a lineup of interchangeable LM blocks and LM rails that can be combined freely as long as they have the same model number.” Any SR35W GK rail of matching accuracy and preload grade makes a correct assembly.

Decoding the designation

SR: THK’s radial-biased LM Guide series, 90° contact angle.

35: size, corresponding to a 34 mm wide rail.

W: block type, bolts mounted from above. THK does not describe SR-W as a “wide type” despite the letter; the companion type is SR35V.

1: THK’s coding field for the number of blocks used on the same rail, not a pack quantity.

SS: end seal plus side seal. DD is double seal, UU is end seals only.

GK: the interchangeable block-only / rail-only series.

Published dimensions and ratings

Assembly height M: 48 mm.

Block width W: 70 mm.

Block length L, with UU or SS seals: 111 mm. Block body L1: 79 mm.

Block mounting hole pattern B x C: 50 x 50 mm; taps 4 x M8 x 12 mm deep.

Mating rail width W1: 34 mm (0 / −0.05). Rail height M1: 27.5 mm.

Rail hole pitch F: 80 mm; hole d1 x d2 x h: 9 x 14 x 12 mm.

Basic dynamic load rating C: 60.4 kN (radial).

Basic static load rating C0: 81.8 kN.

Static permissible moment MA: 0.785 kN·m (one block) / 4.27 kN·m (two blocks).

Static permissible moment MB: 0.482 kN·m (one block) / 2.65 kN·m (two blocks).

Static permissible moment MC: 1.08 kN·m (one block).

Rolling elements: four rows of raceways, 90° contact angle, full complement with retainer plates.

Block mass: 1.2 kg. Rail mass: 6.4 kg/m. Maximum rail length: 3000 mm.

Accuracy grades: Normal, H, P, SP, UP. Preload grades: Normal, C1, C0.

SR35V figures

The SR35V shares a table line with the SR35W in THK’s catalogue and its figures are C 40.9 kN, C0 46.7 kN, block length 77.6 mm, mass 0.8 kg. Every figure published above is the W-type column.

Interchange guidance

Cross-references: SR35W1SS, SR35W1SS(GK), SR-35W1-SS, SR-35V/W, SR35W, SR 35 W, SR35W1UU, SR35W1SSGK. Companion block type in the same size: SR35V. Adjacent sizes: SR30W, SR35TB. The moment values are quoted for one block and two blocks, and the two-block figure is roughly five times the one-block figure rather than double, because two blocks react a moment as a couple across their spacing.