Sheet Metal Cutting Tools: Straight and Bulldog Tin Snips

Why are my cuts coming out so jagged!? Why don't these snips cut a radius well? Why do all of my long cuts A.) Take so long and B.) Have all these little notches every inch or so?

You may or may not have asked yourself these questions or many others while hacking through a piece of tin. 

I've had all these frustrations over the course of my career and some of those issues come down to experience cutting with any kind of tin snip by hand. However, another answer could be that you may be using the wrong snips for the job. One size does not fit all when it comes to sheet metal cutting tools. 

The one tool that I would have gold plated and mounted on the wall of my office is a pair of Straight Tin Snips. They are on the front of our company T-Shirts and will forever be a building block of any micro tin shop.

Straight Tin Snips I use daily

Known as Lather Snips to some, I have always labeled them as straight cut tin snips or shears. I have spent over 15 years of my working life cutting straight duct, plenums and fittings by hand with these and other kinds of tin snips. However, these were by far the Labron James of snips in my Tin Knockers tool bag and on the sheet metal fabrication table.

The manufacturer will tell you wide curves can also be cut, and to a point, you can with the Straight Cut. However, I would argue that the longer handle Bulldog Pattern Snips provide an easier cut when dealing with radius shearing. The Bulldogs are for "nibbling" heavier gauge and they do a great job in that forum. But they do a much better job than the straight cut snips when you have to cut a 40" flat elbow cheek and especially when cutting smaller radius lines by hand. Bulldogs saved me a lot of frustration on those days when fittings prioirized the schedule. 

Bulldog Tin Snips We Use Each Day

The straight cut snips hang up too much as you make your way through the radius. They can't make the corner nice, especially on those tighter curves. Think of a good handling car versus a bad one. Both vehicles can make the turn. However, you can feel the difference if you've driven the car that really handles well in the corner. It can make all the difference when time is of the essence. 

Having both pairs of snips at your disposal can only help your fabrication prowess. 

Every sheet metal worker, roofer or HVAC technician will have a pair of Straight Tin Shears at the ready. They are tried and true; the backbone of a Tin Knockers tool bag. I would bet many of them carry a pair of Bulldogs as well.

Today at K & E Sheet Metal they have taken a back seat to the CNC plasma table and pneumatic jump shear, but they still hold tremendous value in our shop on a daily basis.  They were the tools that built this company to where we could afford the plasma table and jump shear.

If you're working in the field and you don't have a pair in your tool bag, do yourself a favor. And if your're starting a small fabrication shop, they are a must. Those aviator snips you may have picked up at the local Home Depot are immensely important when it comes to sheet metal cutting tools, but they will soak up your time and forearm strength in seconds.

The Straight Cut Tin Snips and Bulldog Pattern Snips will help take care of that problem and keep your cuts straight and true.  

Happy Cutting!

Understanding The Role of an HVAC Ductwork Fabricator

Have you ever heard of the term 'tin knocker'? There's a good chance you have come across the term somewhere along the line. Although, there's also a really good chance you have no idea what I'm talking about.

So what is a tin knocker anyway?

Although there is no real dictionary definition of the term, the accepted definition of a tin knocker is some one works with HVAC ductwork, a sheet metal worker. Meaning someone who fabricates duct and duct fittings for residential or commercial dwellings. Tin knocker can also be assigned to someone who installs ductwork on a regular basis. However, the term 'duct installer' is more common for the men and women working that job.

My daily job, along with co-owner duties, here at K & E Sheet Metal is HVAC ductwork fabricator or tin knocker. I fabricate the components used for the duct running through your home so heat and air conditioning can get to each of the rooms.

Our main business

Our main business is fabricating the plenums, duct, elbows and transitions needed to run the trunk line (ductwork) in the basement or attic. Many times the installer will need to run the duct under existing plumbing pipes or around a corner. Whether the piece needed is a standard fitting or a custom section, contractors or customers will call with measurements for what they need to finish the job. I, as an HVAC ductwork fabricator, build the duct to keep the job moving along.

Method to the madness

Well, in our shop it's a much simpler process than that of the larger, unionized shops knocking out ductwork for major projects around the world. Our facility takes an order from the customer--no job being too small--where I will either enter the dimensions in our computer system running the CNC plasma machine or start the cutting process by hand. Either with had tools or with our 52" wide shear, which is used to cut larger sections of duct.  

After the pieces are cut, I will use our 8' sheet metal brake and other metal bending tools to form the duct fittings and custom sections one flat side at a time. Our ductwork is formed either in half sections or four different sides to create the square or box that will be the duct. This also gives me the chance to run each side through whichever roll forming machine is needed to create the joints necessary for assembling each component.

The assembly process is performed either with a hand held or air hammer, with the air hammer being the quickest form of assembly at our shop. Depending on size or type of fabrication, each piece can take anywhere from 10 minutes to 45 minutes.  

Obviously. this is a very quick overview of what I do as an HVAC ductwork fabricator, but you can get a sense of the basic steps needed and where our services are very important to the installation process. In order to keep the air flow and efficiency at peak you need to have the proper sized duct and fittings to move the air. Therefore a good fabricator is a must for anyone who runs an HVAC installation company. 

Keep the line moving sir

You can equate what I do to a short order cook, who needs to have something done quickly and accurately to keep the line moving. When an order is called in, the time window for me to finish is tight, roughly within 24 hours. With many orders coming through the door, this leaves hours to minutes for getting the fabrication complete, depending on the size of the order. All lead times aren't always a rush, some are weeks or even months down the line. Nevertheless, the majority of what we do in the residential market is a very quick turn around because time frames for many of the homes going up these days is fast.

Other factors that will determine what an HVAC ductwork fabricator produces on a daily basis is the size of his shop, amount of equipment, technological advancement of that equipment and number of employees fabricating ductwork. 

The role of the duct fabricator hasn't changed much over the years, but the size of the shops have. There aren't many job shops like ours around these days giving homeowners and smaller companies the ability to get small orders fabricated on demand for a good price.

If anything, understand that an HVAC ductwork fabricator is an integral part of the construction of your home or commercial building.