Know everything about slotics need not only to locksmiths, installers and other specialists, but also to ordinary people. Such products must correspond to GOST 11871-88. And also have to deal with the end heads of slot-nuts, with round, locking and precision nuts, with the peculiarities of their marking and twisting. In this article, consider everything about slotics.
The slotted nut comes in the most different companies and is present in the range of all leading manufacturers. Technically, this is “just” a metal ring. A thread is applied to the hole of the product from the inside. At the same time, special slots are applied outside, which they gave the name to such fasteners. Such grooves are formed using milling.
The role of grooves – ensuring the scrolling of the metric around its axis. The number of slots must correspond to the cross section of the product. Split hardware is rarely used for conventional threaded joints, but they are very in demand in various industries, namely:
- machine tool;
- Other industries of mechanical engineering.
It is primarily about aggregates that contain trees and other intensively rotating parts. The load on the slotted fastener is very large, so it should be extremely reliable and stable. For its manufacture, only steel strength is applied at least 36 HRS. Minimum hardening depth – 0.1 cm.
Separate types of nuts are used in aggressive media, so they are covered with special protective shells.
Key points are fixed in GOST 11871-88. It applies to round slotted accuracy levels. The following points are normalized:
- denial of the cross section of the thread;
- The step of applying this thread;
- number of slots;
- Theoretical mass of construction.
The control of nuts can be carried out primarily by the visual way. Magnifying devices do not apply, but illumination is required at least 300 lux. In difficult conditions, conventional loupes with a gain of 2.5-3 are used. In the description of the control methods in Standard 11871-88, references to other acts determining the following are given:
- study of tolerances and deviations from them;
- establishment of heat-treated metal hardness;
- the order of comparison with roughness samples;
- rules for checking defects and applied coatings;
- The level of permissible loads on the axis.
It is also useful to pay attention to GOST 11871-80. It covers round slotted nuts with a thread cross section 0.4-20 cm. Categories of accuracy should be a or b. Finally, it is necessary to look at the standard 8530-90, which determines the characteristics of nuts, washers and brackets for fixing and tie sleeves. The size of the heads must be proportional to the diameter of the main cross section.
Thanks to special grooves, install the nut on the put place can be easily and fast. No more difficult and dismantling. What is important, the assembly process passes promptly even in fairly difficult conditions. Stop round slotted nuts needed using multi-phase washers. Such washers are equipped with external “legs”, and one protrusion is located inside. For washers, the provisions of the standard 11872 must be respected. It is worth noting that slotted hardware weigh substantially less than traditional hexagon samples (with comparable parameters, of course). And they also have less radial dimensions.
There are three key types of slotted fasteners:
- in general without chamfer;
- with a simple chamfer;
- with a chamfer, but at the same time with a rounding.
Steel brand 14x17n2, 12x18n10t, 12x18n10t can be used as raw materials. Such materials are taken to increase corrosion resistance. Under normal conditions, “simple” carbon steel categories 20, 35 and 45 are preferred. Applicable alloy alloys of 30khgs, as well as 35x. Only Mark L63 is suitable made of brass.
Steel of the 35th brand is used only for hardware with threads of at least 0.6 and not more than 4.8 cm. It must necessarily carry the load from 13.2 to 240.7 kN. This requirement for factory control, recorded in the standard. It is important that it is why to require certificates with the corresponding marks.
Popular hardware treated with phosphate butter, zinc, cadmium and chromium combination.
The dimensions of the nominal thread diameter can be:
- 200 mm (there are also other dimensions).
Tara marking for fasteners should include the following:
- official trademark (sometimes combined with the name of the firm);
- Conditional signs of hardware;
- Net mass or number in pieces.
Only fasteners of a completely homogeneous type can be invest in each package. That is, if round models are placed there, the square and any other forms cannot be used. The same applies to the size, to the materials and coatings used. Either stainless steel or brass can be applied to the manufacture of slot nuts. Various coating can be applied over the stainless steel metal.
Nuts for locking washers can be categories from HM 3044 to HM 3192. Another possible range – from HM 30/500 to HM 30/710. The mass of nuts in marking is calculated from the assumption of the density of steel 7.85 g per 1 kV. cm. Sometimes applying not trapezoidal, but metric threads – what should also be labeled.
Marking signs are applied to the end surface of the product.
What to twist them?
Perhaps the application is the most important point concerning slotted nuts. By default, they are used to fix strictly coaxial parts. The usual thing is the use of radius (they are also called collet) keys. They have a grip in the form of an arc ending with a trailer similar to the hook. About using a screwdriver, of course, and speech can not.
The state standard fastened 21 key format for any nuts. These keys are made of steel with a chromium additive. Sometimes use a hinge tool. It is enough to have one key for each dimensional group and apply it as needed. In some cases, the end heads helps to work with slotted nuts.
They work even with a small space for fasteners and at the same time reduces the overall deformation of products.
How to make a key for slotted nuts with your own hands, you can learn from the video below.