Knowledge · Linear Motion
Linear rail to length: planning the cut, edge distance T1 and hole pattern
Bringing a profiled rail to the right length is not a saw job for your own workshop. The runways are hardened, the hole pattern has to line up, the edge distance decides the mounting. A cut with an angle grinder or band saw warps the hardened profile and damages the runway; the cooled in-house cut, by contrast, delivers a dimensionally accurate, mounting-ready rail.
On this page
Hardened profiled rails do not belong in your own workshop
The runways of a profiled rail are hardened. A parting cut with an angle grinder or a band saw introduces heat, warps the profile and damages the runway in the cut zone. Even if the length ends up correct, a warped or heat-tinted profile binds and runs unevenly, and the block wears prematurely. That is not a material fault, it is a fabrication fault at the cut.
The second critical point is the hole pattern. The mounting bores sit at a fixed pitch, with a defined edge distance to both ends. Cutting it yourself shifts the edge distance, misses the bore grid or breaks the squareness of the cut face. The rail can then no longer be cleanly bolted down or aligned against the reference edge.
- A cooled, low-stress parting cut that does not temper back the hardened runway.
- A square, deburred cut face as a clean butt and reference surface.
- Edge distances T1 and T2 kept within the allowed limits of the size.
- An intact hole pattern with the correct pitch right to the rail end.
- A documented length and, where needed, a matching cover strip of the same length.
The length formula: pitch, edge distance, number of holes
Rail length follows from the number of bores, the pitch and the two edge distances.
L = (nB - 1) · T + T1 + T2
- L
- rail length in mm
- nB
- number of mounting bores
- T
- pitch (hole spacing) in mm
- T1
- edge distance at the rail start in mm
- T2
- edge distance at the rail end in mm
Size 25, pitch 60 mm, 7 bores
- Symmetric cut (edge distances evenly distributed): T1 = T2 = (T - 4) / 2 = (60 - 4) / 2 = 28 mm.
- Length: L = (7 - 1) · 60 + 28 + 28 = 416 mm, in short L = 7 · 60 - 4.
- These 416 mm are the most ordered length for size 25 at PTS.
Source: Rexroth catalog series R1605 (pitch T = 60 mm, size 25) and PTS invoice data (order length), as of 2026-07.
If you need a fixed overall length, work the bore count backward: nB = floor((L - T1 - T1min) / T) + 1. The edge distance T1 must stay between T1min and T1max of the size. If the edge falls below T1min, the first bore does not seat safely, if it exceeds T1max, the profile end overhangs too far.
| Size | Pitch T | T1min | T1min cover strip | T1max | Lmin | Lmax online |
|---|---|---|---|---|---|---|
| 15 | 60 mm | 10 mm | 12 mm | 50 mm | 80 mm | 4000 mm |
| 20 | 60 mm | 10 mm | 13 mm | 50 mm | 80 mm | 4000 mm |
| 25 | 60 mm | 10 mm | 13 mm | 50 mm | 80 mm | 4000 mm |
| 30 | 80 mm | 12 mm | 16 mm | 68 mm | 104 mm | 4000 mm |
| 35 | 80 mm | 12 mm | 16 mm | 68 mm | 104 mm | 4000 mm |
| 45 | 105 mm | 16 mm | 18 mm | 89 mm | 137 mm | 4000 mm |
| 55 | 120 mm | 18 mm | 20 mm | 102 mm | 156 mm | 4000 mm |
| 65 | 150 mm | 20 mm | 21 mm | 130 mm | 190 mm | 4000 mm |
Edge distance T1 and T2: symmetric or asymmetric
The edge distance is the gap between the rail end and the first mounting bore. T1 sits at the start, T2 at the end. Both must lie within the limits T1min and T1max of the size. The symmetric cut with T1 = T2 is the default: it distributes the support evenly and is the right choice when no mounting position forces a particular edge.
An asymmetric cut (T1 not equal to T2) makes sense when the rail must line up with a defined hole pattern, for example an existing base plate or a butt joint of several rails in a row. Then you fix T1 and let T2 follow from the length and the pitch. Note: in the cover-strip version the minimum edge distance is larger, because the strip has to be fixed cleanly at the end. So check whether you order with or without a cover strip before you set the edge.
Pitch is a series property
The pitch, that is the hole spacing T, is not a free value but is tied to the series. Because the same size can carry a different pitch depending on the R-number series, a replacement cut ordered by size alone misses the existing hole pattern; so always check the part number, not just the size.
Configure your length: price and lead time instantly
Enter size, accuracy, length and edge distance, with or without a cover strip. The configurator checks the pitch limits, computes the hole pattern and shows price and lead time per line, with no login.
Prices and stock are visible in the catalog without signing in.
From stock: cut in-house
The maximum one-piece length is 4000 mm, the stocked bar length. If you need more, the axis is butted from several rails. That is not just a length question but a matter of joint accuracy and the reference edge over the full length. PTS engineers such multi-piece axes so that hole pattern and joint line up across all segments. How to determine size and number of blocks is shown in sizing a linear guide.