BS 3856:1986 download free.British Standard Specification for Slots in platens for projection welding machines.
Foreword
BS 3856 has been prepared under the direction of the Welding Standards Committee. It is a revision of the 1965 edition which is withdrawn. it forms one of a series on resistance welding equipment.
It takes account of certain requirements of ISO 865-1981, published by the International Organization for Standardization (ISO), but there are a number of differences, the chief of these being an Increase in the depth of the upper part of the slot because that given in ISO 865 was considered too shallow for practical working. Compliance with a British Standard does not of itself confer immunity from legal obligations.
1 Scope
BS 3856 specifies requirements for the dimensions, pitch and location of T-slots in platens for projection welding machines. It also gives dimensions for the locating nuts.
NOTE. The titles of the publications referred to in this standard are listed on the inside back page.
2 Definitions
For the purposes of this British Standard the definitions
given In BS 499: Part 1 apply. –
3 Dimensions
The dimensions of the T-slots and the fixing nuts shall comply with the dimensions given in table 1 and shown in figures 1 and 2.
NOTE. Guidance on dimensions for T-slots for general use in machine tools Is given In BS 2485.
The fixing stud and nut shall be assembled as shown in figure 3.
4 Pitch, number and location of T-slots
The pitch of T-slots shall be 63± 0.5 mm. The tolerance of the total dimension between any two T-slots (regardless of the intervening number of slots) shall be ± 0.5 mm. For machines with an electrode force greater than 5 kN, the platens shall have an even number of T-slots. For machines with an electrode force of 5 kN or less, the platens shall have an even or odd number of T-slots, but for an odd number the central slot shall be located on the centreline of the platen.
The lower platen on a machine shall be positioned so that its slots are at 90 ° relative to the slots on the upper platen.
NOTE. Whenever possible, it is recommendod that the upper slots should be parallel to the throat.
5 Designation
The designation of a platen for projection welding with slots complying with BS 3856 shall consist of the number of BS 3856 followed by the number of slots in the platen, the two numbers being linked by a hyphen.