1-rasm


Sovuq keskilar arra yoki qaychi bilan kesilmaydigan og'ir metallni kesish uchun ishlatiladi , chunki odatda joy cheklangan. Ular shuningdek, perchin boshlarini kesish yoki zanglagan yong'oq va murvatlarni kesish va boshqa og'ir ishlar kabi har qanday ta'mirlash ishlarida qo'llaniladi.

Mashina asboblari paydo bo'lishidan oldin , sovuq keskilar umumiy muhandislikda kengroq qo'llanilgan. Metall komponentlar ko'pincha quyish yo'li bilan yakuniy o'lchamga yaqinroq qilingan, shuning uchun metallni shakllantirish bo'yicha ishlarning aksariyati o'choq tomonidan bajarilgan . Keyinchalik aniq o'lchamga keltirilishi kerak bo'lgan quyma joylaridan materialni kesish uchun sovuq keskilar ishlatilgan. Keyinchalik bu joylar to'ldirish va qirib tashlash bilan yakunlandi.

Sovuq keskilar uglerodli asbob-po'latdan yasalgan bo'lib, ular odatda kesmada sakkizburchakdir. Asbob-po'latdan foydalaniladi, chunki u qattiq va qattiq chiqib ketish qirrasini hosil qilish uchun qattiqlashishi mumkin.

Sovuq chiselni qilish uchun asbob po'latining uchini yorqin qizil rangga kelguncha qizdiring va kerakli shaklga bolg'acha uring. Barni bir necha marta isitishingiz kerak bo'ladi, chunki u bolg'acha urganingizda juda tez soviydi. Agar sizda temirchi anvil bo'lmasa, uning o'rniga katta chana bolg'asining yuzidan foydalanishingiz mumkin (agar yuz juda chandiq bo'lmasa). Bolg'ani barqaror ushlab turish uchun uni katta burchakka mahkamlang. Soxta bolg'acha bilan chananing yuziga urmang, aks holda siz qotib qolgan po'latdan yasalgan chiplarni urib tushirishingiz mumkin, bu esa ko'zingizga zarar etkazishi mumkin.

Barning uchi to'g'ri shaklga bolg'a bilan urilgandan so'ng, diagrammada ko'rsatilganidek, kesish chetini maydalashingiz mumkin. Barni qattiqlashtiring, so'ngra yorilib ketmasligi uchun uni qattiqlashtiring. Turli materiallar bir oz boshqacha qirrali silliqlash va temperaturani talab qiladi.

2 -rasmda umumiy foydalaniladigan to'rt turdagi keskilar ko'rsatilgan.

  • The flat chisel is the most widely used and has a place in every workshop and tool kit. It has a broad cutting edge which should be slightly rounded so that the corners do not dig into the metal. This chisel can be used for cutting off rods, cutting out sheet metal, and other jobs of this sort. In the days before machine-made files, a worker would use a special wide and short flat chisel to cut the teeth in a file before it was hardened. 
  • The crosscut or cape chisel is forged so that the cutting edge is slightly wider than the body; this is to ensure that the chisel does not bind in the cut when it is used for deep grooves. As well as cutting single grooves, the crosscut chisel is used to cut a grid pattern of grooves when a lot of material must be cut away from a surface. After the grid pattern has been cut you can use the flat chisel to chip off the remaining square pieces.
  • A round-nose or half-round chisel is used for special work, such as forming flutes and channels. You can cut the oilways on the inside surface of a bearing bush using a round nosed chisel.
  • The diamond-pointed chisel is drawn down to a square section at the end and then ground away to a single bevel. It is used for chipping through plates and cleaning out square internal angles. A tool very similar to the diamond-point chisel is used to cut the teeth on a wood rasp.
Figure 2

How to Use a Cold Chisel

Cutting Sheet Metal

When used to cut sheet metal, the chisel must be held at a slight angle to the surface of the metal as shown in Figure 1. This is done so that when the chisel is struck by the hammer it moves along in a continuous line toward the worker as it cuts through the metal. If the chisel is held vertically, a separate cut is made each time the chisel is struck by the hammer, and the "line" then becomes a series of short cuts. A block of soft iron is generally used for support.

Chiseling Sheet Metal

Figure 3

The method used to cut slots of various shapes and sizes out of a a sheet of metal is similar to that for cutting a straight line. However,the removal of the unwanted metal can be simplified by drilling a series of holes as close together as possible along the outline of the slot before using the chisel. This must always be done when cutting out a slot close to the edge of a sheet (cp. Figure 3); otherwise, the chisel will distort the shape of the plate.

When cutting metal held in a vise (cp. Figure 4), care must be taken so that the line to be cut is as close to the top of the bench vise as possible, so that the metal is not accidentally bent or the edge of the cut badly burred.

Figure 4

Sharpening

All of the chisels described are usually sharpened by grinding, preferably on a wet grindstone. After frequent regrinding, however, the cutting edge becomes too thick. In this case the chisel has to be heated, drawn down to shape, and retempered. The desired thickness of the edge will vary according to the kind of metal that is to be cut; the softer the metal, the thinner the edge of the chisel. 

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AuthorsEric Blazek, Clive Catterall, Jenm6700
Published2006
LicenseCC-BY-SA-4.0
Impact Number of views to this page and its redirects. Updated once a month. Views by admins and bots are not counted. Multiple views during the same session are counted as one.26,510
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