Die Spring, Brown (OD 6-70mm)
Springs · Bore 3–40mm · Length 20–300mm · Outer diameter 6–70mm · 342 options in stock
Compression, extension and die springs for printers and machine builds. The parameters are listed in order of importance: the one at the top decides the most, and no amount of care further down makes up for getting it wrong.
This page lists 342 options: Bore 3–40mm (17 options), Length 20–300mm (30 options), Outer diameter 6–70mm (17 options). From ¥0.56.
The parts of this item
Figure 1 — A spring needs five numbers: wire diameter, OD, free length, coils, end type — miss one and it will not match
What each parameter decides
Every parameter below shows the real range available on this page, and what goes wrong if you pick it wrong. Work through them in this order and you will not go far wrong.
| Parameter | Available here | What it decides | If you get it wrong |
|---|---|---|---|
| Outer diameter | 6–70mm (17 options) | whether it fits into the mounting bore | too big will not go in, too small rattles |
| Bore | 3–40mm (17 options) | whether it slips over your shaft or rod | it will not go on, or it sits loose and slips |
| Length | 20–300mm (30 options) | axial size | too long or too short and it will not go in |
How to choose, step by step
- The three sizes — Outside diameter has to fit the bore, inside diameter has to clear the rod, free length sets the travel. All three, not two.
How the options on this page are distributed
Figure 2 — how the 342 options on this page are spread across each parameter: the bars on the left show how many options sit in each band, the panel on the right shows the real range of every parameter and how many steps it has.
Variant quick reference
| Bore | Outer diameter | Length | Options |
|---|---|---|---|
| 3 | 6mm | 20–300mm (12 options) | 12 |
| 4 | 8mm | 20–300mm (18 options) | 18 |
| 5 | 10mm | 20–300mm (21 options) | 21 |
| 6 | 12mm | 20–300mm (17 options) | 17 |
| 7 | 14mm | 20–300mm (19 options) | 19 |
| 8 | 16mm | 20–300mm (21 options) | 21 |
| 9 | 18mm | 20–300mm (20 options) | 20 |
| 10 | 20mm | 20–300mm (24 options) | 24 |
| 11 | 22mm | 25–300mm (23 options) | 23 |
| 12.5 | 25mm | 25–300mm (22 options) | 22 |
| 13.5 | 27mm | 25–300mm (22 options) | 22 |
| 15 | 30mm | 25–300mm (23 options) | 23 |
| 17.5 | 35mm | 35–300mm (22 options) | 22 |
| 20 | 40mm | 40–300mm (25 options) | 25 |
| 25 | 50mm | 50–300mm (23 options) | 23 |
| 30 | 60mm | 60–300mm (20 options) | 20 |
| 40 | 70mm | 70–300mm (10 options) | 10 |
This table is a summary: one row per Bore, with the other parameters available in that group. For an exact combination, use the selector at the top of the page — it shows the single part number and price.
Reading the part numbers
| Part no. | Configuration |
|---|---|
SPR-BN-10-5-100 | Outer diameter 10 · Bore 5 · Length 100 |
SPR-BN-10-5-110 | Outer diameter 10 · Bore 5 · Length 110 |
SPR-BN-10-5-120 | Outer diameter 10 · Bore 5 · Length 120 |
You can order by part number or by selecting the parameters. The part number is fastest, but it does not always encode every parameter — the selector on this page is the authority.
7 common mistakes
- Compress past solid height and it stays short. A spring taken to coil bind never comes back. Work out the travel before you fit it.
- OD and ID have to both work. It has to drop into the bore and still clear the rod.
- Do not mix rates in one set. In a die with four pockets the stiffest spring takes almost all the load and the others do nothing.
- The seat has to be flat. A spring sitting on an uneven face bends sideways and breaks at a few tens of thousands of cycles.
- Extension springs need initial tension checked. Two springs that look identical can differ by 20% in preload.
- Measure before you order. Take the old part off and measure it, or send us a photo with the caliper reading — that beats guessing from a model number every time.
- Everything here is in millimetres. Where a size is imperial, convert it: 1" = 25.4 mm, 1/4" = 6.35 mm, 3/32" = 2.38 mm.
When to replace it
You do not replace this until it fails — but "still looks usable" and "still reliable" are two different things. Any one of these and it is time:
- Free length noticeably shorter than new — more than about 5% means it has been compressed past its limit.
- Cracks or a broken coil.
- Force clearly down, so ejection or return no longer completes.
Fitting and use
Check before assembly
- Wipe every mating surface with a lint-free cloth. No chips, no burrs, no old grease. One chip is enough to make a bearing noisy.
- Measure the fits — shaft, bore, centre height — against nominal. More than 0.02 mm out and you should check whether you have the right part.
- Check the orientation: the side with the shoulder, step or oil hole has to face the right way. Fitted backwards, it is usually scrap on removal.
Assembly
- Press if you can; do not hammer. If you must tap, use a brass or nylon drift and put the force on the ring that is being fitted, never through the raceway.
- For an interference fit, heat to 80–100 °C first (oil bath or hot plate — never an open flame on a bearing). Hot fitting is easier and safer than cold pressing.
- Tighten fasteners in a diagonal pattern in 2–3 stages. Taking one down fully first distorts the housing and cocks the shaft.
Running in
- Turn it by hand first. It should be smooth, with no tight spot and no axial play. If there is a tight spot, loosen and reseat — do not run it in.
- Run it slowly and unloaded for 10–20 minutes, then feel the temperature. A clear rise means too much preload or poor alignment.
- Re-torque the fasteners after running in, then apply load.
Three things not to do
- Do not hammer. It brinells the raceway, you cannot see it, and it whines forever afterwards.
- Do not mix brands or precision classes in a matched pair. The load shares unevenly and the poorer one always fails first.
- Do not skip lubrication on parts that need it. A few hundred hours dry and it seizes.
Matching parts
- Guide rods — 1–2 mm smaller than the inside diameter
- Flat washers under the seat
Lead time, custom work and shipping
- Stock sizes: dispatched in 1–2 working days, subject to stock
- Custom: non-standard sizes, materials and treatments are possible — send quantity and drawing
- Shipping: from Shenzhen; domestic courier by default, DHL or dedicated line for export
- Volume: quantity pricing available, contact us for a quote
If you cannot find the size you need, or you are not sure which one fits, send us the problem you are solving — what machine it goes on, the dimensions of the part you have, what it has to achieve — and we will match it.