When you start to create more complicated and high-precision parts on either your wood or metal lathe, you will need new tools. A common tool that machinists prefer to make on their own is a lathe dog, which means that you may want to create your lathe dog to use.
The simples lathe dog can be created using an oversized nut, a long bolt, a small nut, and a tool holding nut. Cut the oversized bolt to be threadless, then cut a small hole in it, welding the long bolt onto it and bending it between 90° to 75° to be held onto the by the chuck.
It is essential to know that two types of lathe dogs are commonly used, the straight tail lathe dog and the bent tail carrier. It is much easier to create a bent tail lathe dog, while a straight tail lathe dog can require some precision that can cause you to work on the simple piece for a few days.
What Is The Purpose Of A Lathe Dog?
If you are cutting a cylindrical piece between two centers, you will need to use a lathe dog or lathe carrier to transfer the turning motion to your part. The lathe dog allows you to cut with high precision according to the center holes or the center hole.
The lathe dog does what the three-jaw or four-jaw chuck would typically do, causing the part to turn according to the speed set for the machine. However, because of the size of the lathe dog, the machine will have to have its speed turned down to ensure the unbalanced load is not a problem.
We always recommend spending a bit of extra time on your lathe dog to ensure that it won’t cause you problems when you start cutting. A lathe dog will often be used with wooden pieces that are oddly shaped, as you can easily drill a hole straight through the piece and center everything with the two centers.
What Are The Tools You Will Need To Create Your Lathe Dog?
With the knowledge of how to use a lathe dog thoroughly understood, we need to start looking at what tools you will need. Unlike most other pieces you can build yourself, the lathe dog is something you want to create once and never have to worry about again.
The best lathe dogs require some work and can be used across lathes to help you ensure that the parts you are cutting will always be perfectly centered. You can create a lathe dog with a few simple hand tools, but we recommend that you have the following tools when building the best lathe dog.
- Metal Lathe: Having a metal lathe will ensure that you can cut any piece of round stock into the right shape, including cutting the hole in the middle. If you keep everything simple and use an oversized bolt, the lathe will help you remove the threads easily.
- Grinder: A grinder is the best tool to deburr everything and ensure that you have a completely smooth finished workpiece. We always recommend that you have a proper grinder to ensure that everything will be smooth and finished properly.
- Milling Machine: A milling machine with several cutting heads will ensure that you can cut much more complex shapes into your new lathe dog. Many people prefer to use a milling machine to cut and tap any of the holes that will be used on the lathe dog.
- Oxy-Acetylene Torch: You won’t need to weld the pieces of the bent tail onto the lathe dog using the torch. However, we recommend that you use it to help you create the perfect bend in your tail to ensure that you won’t have to create complicated alternatives.
- Round Bar: The bent tail or straight tail you are using should preferably be made out of a piece of round bar. This will allow it to easily attach to the faceplate of the center without needing to be shaped, ground, or cut with too many issues.
- Bolt: We always recommend using machining bolts when securing the lathe dog onto the piece that you are cutting. These bolts don’t rust away when exposed to the oils and coolants generally used when cutting on metal lathes and won’t overheat when cutting on a wood lathe.
- Cutting Tools: High-speed steel cutting tips or tungsten carbide tips will be required to cut through the material you need. We always recommend having these on hand when working with a metal lathe or mill, as these will be the tools you need to use.
- Welding Tools: Everyone has their welding equipment and has practiced how to use these in the way that best suits them. We recommend that you use the welding style that you are best with, as the lathe dog will be put under immense inertial pressure when used.
Which Materials Are The Best To Use To Build Your Lathe Dog?
We have seen every kind of material used to create lathe dogs, and we have seen many of these materials fail. However, we recommend using either mild steel or aluminum to get the best possible lathe dog that will allow you to have one that lasts for much longer than you may expect.
Using plastic or wood often means that you have a lathe dog that begins to fail when you start spinning at speeds. There are a few reasons you would have to use mild steel or aluminum, and we will cover them from start to finish.
Mild Steel Lathe Dogs
The best but hardest material to create your lathe dog is mild steel; the material is extremely easy to work with and will allow you to customize as needed. Mild steel is also affordable, allowing you to create a few lathe dogs that will be different sizes and allows you to try several times.
Lathe dogs that lathe manufacturers provide are usually cast iron with mild steel parts that have been machined to work perfectly. Simple lathe dogs are often created out of scrap mild steel that most people have to lie around the workshop.
Aluminum Lathe Dogs
Aluminum lathe dogs don’t cause such a large imbalance when you cut and will be better for working on a wood lathe. Many people who make lathe dogs out of nuts will have aluminum lathe dogs because most bolts and nuts are made out of aluminum, especially when going into larger sizes.
If you are working with a wood lathe, then aluminum will mean that you can easily create a lathe dog that can turn at much higher speeds. With a straight tail lathe, dogs will usually spin at even faster speeds, allowing people to easily make high-speed precision cuts.
What Are The Steps To Cutting Your Own Bent Pin Lathe Dog?
Now that you have the materials and the tools ready, we can start cutting your lathe dog, which is not as difficult as most other parts that you will create. However, if you aren’t doing it properly, you may have a lathe dog that slips as you cut on the piece you are turning.
The best lathe dog will be one that does everything you need it to do but may cause problems to others. Most machinists and artisans have their lathe dogs made to work with their lathes and help them create pieces that work properly no matter how large the pieces may be.
1. Shaping The Lathe Dog
The first step is to cut the opening for your lathe dog; depending on what you are using, this may require a cutting tool on your lathe or an end mill on a milling machine. You need to cut the outside of the lathe dog first and ensure that it is round and smooth; then, you can cut the inside diameter.
Many people prefer a lathe dog that is not perfectly round on the inside diameter, allowing the set screw to push the part into the perfect position. If you are using a nut, you need to ensure that threads have been removed entirely and that the piece is sanded smooth.
2. Drilling And Cutting The Holes On The Lathe Dog
Three holes need to be cut on the lathe dog, one of which needs to be threaded to allow the set screw to work properly. The first hold needs to be just a few millimeters larger than the rod you are using, allowing you to put the rod into it and helping secure it when you are welding it.
If you have a milling machine, you can cut the holes and create the threads as you need them. However, a drill press or a hand tap can be used to drill the holes and tap the ones that you need to have tapped, with many round lathe dogs having several set screws to ensure a proper grip.
3. Bending & Welding The Bar For The Lathe Dog
Before welding the bent tail onto your lathe dog, we recommend bending it at the angle that you need it to be in. This will save you many headaches, as the last step in the process will be to weld on the bent tail to ensure the best possible fit without damaging the lathe dog.
Many people mistake welding the tail onto the lathe dog before they bend it, which damages the lathe dog. Clamping the lathe dog into a vice can cause it to be bent, which means that you need to unbend it, causing headaches as your newly created lathe dog won’t function properly.
4. Testing The Fit Of The Lathe Dog Parts
Once you have created your lathe dog, you will need to test fit it on your lathe using the two centers. Many people make the lathe dog and assume that it works perfectly, then start immediately cutting on their main piece, which causes imperfections and off-center cuts.
We recommend testing the lathe dog on a piece of scrap material that you may have to ensure that the new lathe dog will work perfectly. Doing this will ensure that your parts are not damaged beyond repair, with many people not ensuring that their lathe dogs are working properly before using.
Why Is A Lathe Dog Used?
Unlike a chuck, when using two centers, there is no direct contact with the part you are cutting and the lathe center. Instead, you will install a faceplate with a center and use the lathe center to have the part you are cutting.
The lathe dog transfers the lathe’s rotation onto the part you are turning by using the bent tail or the straight tail to connect to the lathe. This is why your lathe dog needs to have a tail that is connected properly with the lathe dog and to have the lathe dog securely connected to the piece.
If you are unsure about building and using a lathe dog, we always recommend that you buy a lathe dog from a lathe manufacturer. This will mean that the lathe dog is perfectly shaped and that you won’t have to stress about odd shapes, and the lathe dog will always work perfectly.
Creating a lathe dog is something that most artisans and machinists will try to do, and when creating your first one, you should try to keep it as simple as possible. We recommend ensuring that your lathe dog is sturdy and easy to use and attach to the lathe and parts you are machining.
Whatever you do, don’t always assume that you can cut the perfect piece using only a chuck.