Joints and Seams

Question 1

Edge distance refers to the distance between the edge of the material and the ____________ of the fastener that will be used to secure the seam.

Answer 1

Centre

Question 2

The minimum recommended edge distance for fasteners is?

Answer 2

2 times the fastener diameter

Question 3

Thicker material will allow a ___________ pitch to be used.

Answer 3

Larger

Question 4

Why are lap seams not spot welded at the ends first to hold them in place while fabricating the seam?

Answer 4

If the object is spot welded at either end first and the spot welds in the middle filled in later, buckling may occur.

Question 5

What is the advantage of rivets over screws or bolts

Answer 5

Rivets are a means of fastening a lap seam in a more permanent manner than with screws or bolts.

Question 6

The pop rivet is a type of

Answer 6

Blind Rivet

Question 7

What is the allowance for grooved seams which are lighter than 22-gauge?

Answer 7

Three times the width of the seam (3W)

Question 8

When setting the fingers of the barfolder, the fingers should be set

Answer 8

The width of the seam minus 2 metal thicknesses.

Question 9

After hooking the folded edges of the grooved seam together, you should

Answer 9

Set the seam tight.

Question 10

The Noyes groover can only form outside grooved seams.

Answer 10

False; the Nooves groover has grooves machined in the rail to allow it to form inside grooved seams.

Question 11

How many brakes are on a rectangular hammerlock?

Answer 11

Three

Question 12

If the seam used to fabricate the project is _______________, a more specialized notch is required. This notch is called the hammerlock notch.

Answer 12

Grooved Seam

Question 13

The dovetail seam is normally a field fabricated seam

Answer 13

True

Question 14

The pocket will not change with the adjustment of the feed guide. The pocket will always be

Answer 14

3/8” deep

Question 15

When running material through the Pittsburg Lock former, the inside of the fitting or duct should always face _________.

Answer 15

Up

Question 16

For fittings with curved cheeks such as rectangular duct elbows, offsets, and Y-branches the edge turned up is generally

Answer 16

3/16”

Question 17

When folding the male part of a Pittsburg Lock in a brake or cheek bender, you should allow

Answer 17

1/4”

Question 18

The button, or snap, lock on a rectangular duct is used for _____________ pressure classes of duct construction.

Answer 18

Lower

Question 19

Describe a Lap seam

Answer 19

A common, easy to fabricate and simple to assemble seam. Formed by laying one section of material over another. The overlap will always equal the seam allowance. Then it is fastened together.

Question 20

What is “edge distance”

Answer 20

The distance between the edge of the material and the centreline of the fastener that will be used to secure the seam.

Question 21

What is “fastener pitch”?

Answer 21

The distance between the centreline of the fasteners on a seam.

Question 22

List the factors when deciding fastener pitch

Answer 22

Thickness of material, Blueprint directions, Common sense and experience,

Question 23

How do you lay out the calculated fastener pitch?

Answer 23

Divide the pitch in half and starting at one edge with a 1/2 pitch distance measure and mark the calculated spacing for each fastener.

Question 24

Describe an offset lap seam

Answer 24

A simple lap seam with two pieces of material laying over one another, but one is slightly offset before the seam allowance to make the seam flat on one side.

Question 25

What is the lap seam allowance?(maximum and minimum)

Answer 25

One times the width of the lap seam.(maximum)

four times the fastener diameter (minimum).

Question 26

Describe a corner lap seam

Answer 26

A lap seam bent at 90 degrees to make a corner on a project.

Question 27

What are the two types of corner lap seams? Describe what makes them different

Answer 27

An outside corner lap seam is when the lap (w) is on the outside, and the other piece of material tucks underneath and is then fastened. An inside corner lap seam is when the lap is on the inside of the seam, and an 1/8th of an inch is added to the net pattern of the top piece to bend over the inside of the lap.

Question 28

Describe the proper way to complete a spot weld

Answer 28

check the spot welder tips to make sure they are aligned, sharp, and clean. Do a test spot weld on scrap piece of metal of like material and thickness. Adjust the settings of the spot welder if necessary.

Question 29

What is a solid rivet?

Answer 29

The solid rivet is a rivet with a head formed on one end. (tinners rivet). These require access to both sides of the metal, and are placed and set by hand with a hammer.

Question 30

Explain a grooved seam.

Answer 30

Two pieces of metal folded over, hooked together and an offset formed to lock the seam and keep it from coming apart. Most commonly used on round products.

Question 31

How is a groove seam formed?

Answer 31

They are most commonly formed by hand, using a barfolder. they require 1 fold on each piece of material.

Question 32

Describe a hand groover, and its purpose.

Answer 32

Multiple different sizes of metal tools, all hand held and aided with a hammer. Each size has a different slot, on which the slot notched into them will be thinner or wider. (used for different seams). The purpose is to tighten and finish the groove seam so that it cannot come apart.

Question 33

What is a groove stake?

Answer 33

It is a stake used to set the groove seam, along with the hand groover. It has two round bars coming off the middle of it, one being thicker in diameter than the other. Both having notches along the length of the bars for the underside of the groove seam to rest in.

Question 34

Explain a Noyes groover and its purpose

Answer 34

It is a machine, that is designed to form grooved seams in one operation. It is especially useful on longer seams. It can form both inside and outside seams.

Question 35

What kind of seam is a “tapin”

Answer 35

A flanged connection seam

Question 36

Explain a hammerlock and it’s most common place.

Answer 36

A hammer lock is a flanged connection seam used on rectangular fittings mostly. usually used on take offs. one end of the fitting has a formed seam, either 3/4” or 1/2”.

Question 37

How is a hammerlock seam formed?

Answer 37

3W is added to the net pattern of the fitting, then 2 lines are scribed where the hammerlock seam will be on the fitting. (3/4” or 1/2”). The first line is folded at 90 degrees from the net pattern line. The second is folded over as far as the bar folder will allow. the third is folded over at 90. The second fold is then squished tight to form the hammerlock seam. Lastly, the last fold at 90 degrees is notched in a “dovetail” fashion for easy install in the field.

Question 38

How is hammerlock used on a round fitting?

Answer 38

Mostly used on round Tapins. (roof jacks, vent cones for chase tops.) It is formed using the rotary machine with a number of different rolls. A stop(small bead) needs to be formed where the seam will end, to stop the other piece of material from sliding too far over. Then the seam is rolled through the crimp roller.