This web site is designed to answer some common questions about instrument precision shafting and related products. If your question is not answered here, please use the contact form at the bottom of this page and we will do our best to find the answer. The information on this site relates to shafting product imported to Australia by Miniature Bearings Australia.
INDEX
Many types of shafting are available including high precision, low precision, smooth, threaded and pipe shaft. We list below some of the more common types.
Aluminium Shafting |
Recommended for use with Igubal Drylin bearings only |
Ground Precision Shafting |
Ground precision shafting is available in 303 and 316 unhardened stainless steel, 17-4PH and 400 Grade hardened stainless steel. It is also available in various high carbon steels such as Ck53/Cf53 Chrome Vanadium Alloy, C1060 Case Hardened, 12L14 Cold Rolled Steel and Silver Steel (tool steel). |
Nickel Plated Steel - Unhardened |
This is a commercial grade shafting available only in a limited number of sizes. The tolerances on this shafting are not specified, however it is suitable for bearing and pulley applications in hobby applications. Not recommended for precision applications. |
Pipe Shafting |
Reduces Weight Applications where a cord or cable may need to pass out of sight from one end to the other. |
Pipe Shafting |
Reduces Weight Applications where a cord or cable may need to pass out of sight from one end to the other. Recommended for use with Igubal Drylin bearings only. Not recommended for use with standard bearings. |
Pre-drilled
shafting |
Drilled and tapped ready for mounting on a rail support. |
Shafting with
rail supports |
Ready mounted shafting for use with linear motion bearings. |
Predrilled
aluminium shafting with rail supports |
Recommended for use with Igubal Drylin bearings only. |
Drill Rod |
For punches dies and high strength machine parts. Unhardened - requires heat treatment. |
Pinion Shafts |
Designed to press fit small pinion gears. |
Flexible Shafts |
Made from tightly wound helical coil springs wrapped around a centre wire. Because of its construction, the shaft can be bent, without fracture, to a much smaller radius than a solid shaft of the same outside diameter. The shaft is connected to the power source and the driven member by either coupling fittings or panel mountings. |
Non Precision Rod
- Brass
|
For Hobby Applications. Not recommended for mounting of precision bearings. |
Non Precision Rod
- Aluminium |
For Hobby Applications. Not recommended for mounting of precision bearings. |
Non Precision Rod
- Stainless Steel |
For Hobby Applications. Not recommended for mounting of precision bearings. |
Threaded Shafting for Ball Screws |
Threaded shafting used in conjunction with a ball nut changes the turning motion of the screw into a
linear motion of the nut. |
303 is a free-machining stainless steel. The free-machining characteristics are provided by adding sulphur and/or selenium. Using 303 stainless steel can be more cost effective than using other stainless steels since 303 takes less time to machine, machine tool bits will last longer. 303 is similar to 304 grade (A2 or 18/8) but is easier to machine.
304 stainless steel is easy to machine and very widely used. Due to the wide usage, 304 stainless steel is usually cheaper than other grades when purchased in the unmachined form. It should always be remembered though, that finished machined parts have their own input costs. It can't be assumed that two similar sized shafts will be cheaper in 304 stainless than in 316 stainless simply because the base material cost is cheaper.
316 Stainless Steel is used when the product will be exposed to a highly corrosive environment. 316 stainless steel contains molybdenum. The nickel content is 10%. Molybdenum, in conjunction with chromium, provides superior resistance to corrosion due to chlorides. 316 stainless steel is subject to attack if very high levels of chlorine are used for extended periods of time.
316 stainless steel is non-magnetic. Its machinability is similar to 304 stainless steel, and its material cost is usually much higher than 303 or 304 stainless steel. 316 steel is used in the manufacture and handling of food and pharmaceutical products where it is often required in order to Minimise metallic contamination. It is also known as "marine grade" stainless steel due to its increased resistance to chloride corrosion compared to type 304.
The aluminium shafting is produced by Igubal and is recommended for use with Igubal Drylin Bearings only. It is light weight and easy to machine. It is relatively soft and is not recommended for supporting linear ball bearings.
Also known as 630 Stainless Steel containing 17% chromium and 4% nickel. Precipitation-hardening martensitic stainless steels have corrosion resistance comparable to austenitic varieties, but can be precipitation-hardened to even higher strengths than the other martensitic grades.
Martensitic stainless steels, with lower chromium levels, no nickel, and high carbon content, these steels may be heat-treated to have favourable characteristics of high strength and toughness. Some common 400 grades include 416 and 440C. The material is magnetic and corrosion resistance is not as great as 300 grades.
A magnetic mid grade alloy used for it's strength, durability and magnetic properties. It can be hardened, and is easy to machine due to additional sulphur.
Contains more carbon which allows for much better edge retention when the steel is heat treated properly. It can be hardened to Rockwell 58 hardness, making it one of the hardest stainless steels.
A high strength steel which is often used for linear bearing shafting due to it's ability to be hardened and ground to very smooth finishes. Not corrosion resistant.
A high strength steel which is often used for linear bearing shafting due to it's ability to be hardened and ground to very smooth finishes. Not corrosion resistant.
Also known as Lead Steel, it is easily machinable. Not weldable due to high sulphur content. Unhardened.
Also known as tool steel or drill rod. Used for general purpose applications. Due to the high carbon content this product is very shiny, but it lacks the corrosion resistance of stainless steel.
Standard unhardened steel with a nickel plating for corrosion resistance and a shiny appearance.
The main component of these steels is Fe (Iron) with the addition of the elements shown in the following chart.
| Chrome Steel | ||||||||
| % Composition | C | Si | Mn | P | S | Ni | Cr | Mo |
| Grade SAE52100 (SUJ2, 100Cr6) | <0.95 ~ 1.10 | <0.15 ~ 0.35 | <0.501 | <0.026 | <0.026 | - | 1.30 ~ 1.60 | <0.081 |
| Austenitic Stainless | ||||||||
| % Composition | C | Si | Mn | P | S | Ni | Cr | Mo |
| Grade 303 (SUS303, 303S31, X8CrNiS189, 1.4305) | <0.101 | <1.001 | <2.001 | <0.046 | >0.15 | 8.00 ~ 10.00 | 17.00 ~ 19.00 | - |
| Grade 304 (SUS304, 304S16, XDCrNi189, 1.4301) | <0.081 | <1.001 | <2.001 | <0.046 | <0.031 | 8.00 ~ 10.50 | 18.00 ~ 20.00 | - |
| Grade 316 (SUS316, 306S16, X15CrNiMo1810. 1.4401) | <0.081 | <1.001 | <2.001 | <0.046 | <0.031 | 10.00 ~ 14.00 | 16.00 ~ 18.00 | 2.00 ~ 3.00 |
| Martensitic Stainless | ||||||||
| % Composition | C | Si | Mn | P | S | Ni | Cr | Mo |
| Grade 410 (SUS410, 410S21, X10Cr13, 1.4006) | <0.151 | <1.001 | <1.001 | <0.041 | <0.031 | <0.601 | 11.50 ~ 13.50 | - |
| Grade 416 (SUS416, 416S21, X12CrS13, 1.4005) | <0.151 | <1.001 | <1.251 | <0.041 | <0.031 | - | 12.00 ~ 14.00 | - |
| Grade 440C (SUS440C, AISI440C, X102CrMo17, 1.4125) | 0.95 ~ 1.2 | <1.001 | <1.001 | <0.041 | <0.031 | - | 16.00 ~ 18.00 | <0.751 |
| Ferritic Stainless | ||||||||
| % Composition | C | Si | Mn | P | S | Ni | Cr | Mo |
| Grade 430 (SUS430, 430S17, X8Cr17, 1.4016) | <0.121 | <0.751 | <1.001 | <0.041 | <0.031 | <0.601 | 16.00 ~ 18.00 | - |
High precision shafting can be used in combination with ball bearings, roller bearings or bushes for rotating motion or linear bearings for reciprocating motion. Shafting used for linear motion bearings needs to be sufficiently smooth and hard so that neither the balls nor the shaft are damaged as the balls run along the shaft.
|
|
Threaded shafting such as those used with ball nuts or lead nuts convert the turning motion of the shaft into a linear motion of the nut.
 Ball Screw and Nut |
 Lead Screw and Nut |
Brass, Aluminium and Stainless Steel Rod generally have a wider tolerance range than precision shafting and the tolerances are usually + and -, so it is not always going to be easy to get a good fit with a precisely undersized tolerance part such as a bearing. Rods are better suited to design and hobby work.
In many precision applications it is important to use a sufficiently precise shaft. Applications involving the use of precision bearings require very precise shafting since the standard tolerances on bearing bores up to 30 mm are +0.000/-0.010. A suitable shaft tolerance should therefore be selected to achieve the desired fit.
Shafting tolerances are usually listed in the specifications for each type.
The following chart can be used as a general guide
| High Precision Types | Low Precision Types |
|
|
The hardness of shafting is the property that enables it to resist deformation. Depending on the application, the hardness may be an important consideration - especially in high load applications. Hardness testing is based on experiments and observation.
There are several methods of testing hardness including Brinell, Rockwell and Vickers which all use an indentation test. There are other hardness testing methods not discussed in this document.
The Rockwell C hardness test is performed by pressing a cone-shaped test piece into the boundary layer of material with a defined pressure. The remaining impression depth is measured.
For the Rockwell B procedure a steel ball is used instead of a cone.
The Vickers test presses the point of a pyramid of diamond into the surface of the working piece for 10-30 seconds with a defined pressure. The diagonal of the resulting imprint of the pyramid is measured.
The Brinell hardness test is performed by pressing a tungsten carbide ball into the material surface for more than 10 seconds with a defined pressure. The Brinell hardness is determined from the diameter of the impression.
There is no exact formula for converting the results of one type of hardness test to another, however the table below gives a nearest approximation based on test results.
Hardness Scales |
Tensile Stress Equivalents |
|||||
Rockwell C
|
Vickers
|
Brinell
|
Tons/in2 |
1000lb/in2 |
kg/mm2 |
MPa |
| 67.7 | 900 | |||||
| 67.0 | 880 | |||||
| 66.3 | 860 | |||||
| 65.5 | 840 | |||||
| 64.8 | 820 | |||||
| 64.0 | 800 | |||||
| 63.3 | 780 | |||||
| 62.5 | 760 | |||||
| 61.7 | 740 | |||||
| 61.0 | 725 | 630 | ||||
| 60.5 | 710 | 627 | ||||
| 60.0 | 698 | 601 | 132 | 295 | 208 | 2039 |
| 58.9 | 670 | 578 | 127 | 284 | 200 | 1961 |
| 57.1 | 630 | 555 | 122 | 273 | 192 | 1884 |
| 56.1 | 609 | 534 | 117 | 262 | 184 | 1807 |
| 54.4 | 572 | 514 | 112 | 250 | 176 | 1729 |
| 51.9 | 532 | 495 | 108 | 241 | 170 | 1668 |
| 50.7 | 517 | 477 | 105 | 235 | 165 | 1621 |
| 49.5 | 497 | 461 | 101 | 226 | 160 | 1559 |
| 47.5 | 470 | 444 | 98 | 219 | 155 | 1513 |
| 46.0 | 452 | 429 | 95 | 212 | 150 | 1467 |
| 44.8 | 437 | 415 | 92 | 206 | 145 | 1420 |
| 43.7 | 422 | 401 | 88 | 197 | 139 | 1359 |
| 42.4 | 408 | 388 | 85 | 190 | 134 | 1312 |
| 41.3 | 395 | 375 | 82 | 183 | 129 | 1266 |
| 39.9 | 381 | 363 | 80 | 179 | 126 | 1235 |
| 38.8 | 370 | 352 | 77 | 172 | 121 | 1189 |
| 37.7 | 359 | 341 | 75 | 168 | 118 | 1158 |
| 36.7 | 349 | 331 | 73 | 163 | 114 | 1127 |
| 35.0 | 337 | 321 | 71 | 159 | 111 | 1096 |
| 34.0 | 327 | 311 | 68 | 152 | 107 | 1050 |
| 33.0 | 318 | 302 | 66 | 147 | 104 | 1019 |
| 32.0 | 308 | 293 | 64 | 143 | 101 | 988 |
| 30.9 | 300 | 285 | 63 | 141 | 99 | 973 |
| 29.8 | 292 | 277 | 61 | 136 | 96 | 942 |
| 29.0 | 284 | 269 | 59 | 132 | 93 | 911 |
| 27.5 | 275 | 262 | 58 | 130 | 91 | 895 |
| 26.6 | 269 | 255 | 56 | 125 | 89 | 865 |
| 25.2 | 261 | 248 | 55 | 123 | 87 | 849 |
| 24.3 | 255 | 241 | 53 | 118 | 84 | 818 |
| 23.0 | 247 | 235 | 51 | 114 | 81 | 787 |
| 22.0 | 241 | 229 | 50 | 112 | 79 | 772 |
| 20.8 | 234 | 223 | 49 | 110 | 77 | 756 |
| 228 | 217 | 48 | 107 | 76 | 741 | |
Rockwell B
|
Vickers
|
Brinell
|
Tons/in2 |
1000lb/in2 |
kg/mm2 |
MPa |
| 98 | 222 | 212 | 46 | 103 | 73 | 710 |
| 97 | 218 | 207 | 45 | 101 | 71 | 695 |
| 96 | 212 | 197 | 43 | 97 | 68 | 664 |
| 93 | 196 | 187 | 41 | 92 | 65 | 632 |
| 91 | 188 | 179 | 39 | 88 | 62 | 602 |
| 88.5 | 178 | 170 | 36 | 81 | 57 | 556 |
| 86 | 171 | 163 | 35 | 78 | 55 | 540 |
| 84.2 | 163 | 156 | 34 | 76 | 54 | 525 |
| 82 | 156 | 149 | 32 | 72 | 51 | 494 |
| 80 | 150 | 143 | 31 | 69 | 49 | 479 |
| 77 | 143 | 137 | 30 | 67 | 48 | 463 |
| 75 | 137 | 131 | 29.5 | 66 | 47 | 455 |
| 72.5 | 132 | 126 | 29 | 65 | 46 | 448 |
| 70 | 127 | 121 | 28 | 63 | 44 | 432 |
| 67 | 122 | 116 | 26 | 58 | 42 | 401 |
When joining shafts, angular and parallel misalignment and shaft axial movement needs to be factored into all joining design (couplings, universal joints etc). Some couplings can accommodate very little or no misalignment whilst other styles are quite tolerant. Misalignment is an important factor in almost all designs using joined shafts.
|
Distributors and Resellers please contact Miniature Bearings Australia for information on distributing the MBA product range.
Small Parts and Bearings online store. Small Parts and Bearings distribute the entire range of MBA product with a "help yourself" online store.
Hobby Engineering Supplies counter sales. Hobby Engineering Supplies is based in the MBA building and offer the full range of MBA product via a counter service.
Austenitic - Austenitic stainless steels are effectively nonmagnetic in the annealed condition and can be hardened only by cold working. Some ferromagnetism may be noticed due to cold working or welding. They typically have reasonable cryogenic and high temperature strength properties. Chromium content typically is in the range of 16 to 26%; nickel content is commonly less than 35%.
Chamfered - Chamfered edges refer to a small bevel on the edges of the shaft. Chamfered edges assist with the location of components on the shaft.
DIN - Standards for materials as set by Deutsches Institut für Normung E.V. DIN Specifications can be purchased from www.nssn.org/
Fit - The degree of contact between two mating surfaces such as a bearing bore and a shaft. Different applications require different fits. A slip fit is one where there is a small amount of clearance between the two mating parts allowing them to slide together quite easily. An interference fit is one where the actual sizes of the two mating parts overlap requiring a certain amount of pressure to assemble (eg. A shaft of around 7.994mm and a bearing of around 7.992mm bore).
Ferritic - Magnetic stainless steels that have a low carbon content and contain chromium as the main alloying element.
Ferromagnetism - Magnetism due to the presence of iron.
HBW - Brinell Hardness
HRB - Rockwell Hardness B Scale
HRC - Rockwell Hardness C Scale
HV - Vickers Hardness
Linear Motion - Movement along a shaft as distinct from rotary motion which is movement around a shaft.
Martensitic - Martensitic stainless steels are alloys of chromium and carbon. They are ferromagnetic, hardenable by heat treatments, and are usually less resistant to corrosion than some other grades of stainless steel. Chromium content usually does not exceed 18%, while carbon content may exceed 1.0 %.
Precipitation Hardening - An alloy strengthening method. Performed with two heat treatments that result in the growth of extremely small uniform particles. The small particles strengthen the metal.
RA - Roughness Average which is an average of the peaks and valleys of a material's surface profile.
RMS - Root Mean Square is an alternative method of measuring the surface roughness. The value for RMS is generally about 10% higher than the RA value for the same surface.
Rotary Motion - Movement around a shaft as distinct from linear motion which is movement along a shaft.
Tolerance - The permissible limit of variation from the nominal size. For example an 8mm shaft may be represented as 8.000 mm +0.000 / - 0.008 which would mean that the actual shaft size may be anywhere from 7.992 and 8.000 mm.
µm - Micron or thousandth of a millimeter (0.001mm).
|
|
|
|
|
|
|
|
A detailed online catalogue is available by following the link to the Miniature Bearings Australia Online Catalogue. Downloadable PDF catalogues are available from the Miniature Bearings Australia FTP Site. The catalogue includes a large range of shafting, gears, belts, pulleys, bearings, springs, dowel pins, gearboxes, motors and much more. Miniature Bearings Australia are a wholesale only company and their product is available worldwide through a network of distributors. Hobby Engineering Supplies have negotiated for office and warehouse space within the MBA building and have direct access to all of the MBA product for counter sales. If you prefer to order online, you may like to visit the Small Parts and Bearings online store. Small Parts and Bearings offer the entire MBA product range through a "help yourself" online store.
Don't be caught out by unfair and biased terms in contracts. The Unfair Contracts web site highlights Australia's need for government regulation of the terms and conditions that may be included in consumer contracts. The Cleanaway Brisbane contract terms shown on the site are of particular interest. This site alerts us to just how much a company can get away with - legally.
For a great Trivia game see the online interactive trivia with over 1700 questions on the Coldrick web site.
