I’m working on a new woodworking project that involved cutting through-slots for bolts in a couple of boards. The two boards will act as adjustable arms to hold a dowel handle for a garden cart.
Slab doors allow you to match existing jambs by cutting the mortise slots into the side of the door by yourself. The chisel begins to cut and curl the wood up to the point of the tracing. Turn empty wall space into storage space with slotted shelves. DIYNetwork.com experts show how to make a slotted shelf of any size. To make wider slots, use a chisel and a hammer to cut out the area between each set of slots. Cut the Strips of Wood; Step 2: Cut Between Each Slot Set; Step 3: Screw the Wood to the Board; On TV See Full. Cut Between Each Slot Set. To make wider slots, use a chisel and a hammer to cut out the area between each set of slots.
I have cut shorter and narrower slots using a table-mounted router for a coin bank. These bolt slots were considerably longer and 1/4' wide so I was reluctant to use the same technique. I don’t have a plunge router – which would probably be the fastest and easiest way to do this.
Crowd-sourcing ideas
After checking a couple of woodworking forums for ideas – including one where someone trying this on a router table said the board 'shattered' (yikes!) – the general consensus seemed to be todrill out most of the material and clean up the slot later with a coping saw.
That sounded good (and safe) to me.
Since my slot was only 1/4' wide, I decided best approach was to use a 1/4' Forstner bit in a drill press to define the slot and remove most of the material, then clean up the slot with a file and sandpaper.
Slot Into Place
The shaft on the 1/4' bit was larger than the bit itself so I had to flip the board over to drill all the way through the 3/4' material. It’s probably a good idea to do this anyway to avoid tear-out unless you have a backer board underneath when you’re drilling.
What to do
Drilling
- Mark the centre points for each end of the slot in the blank and use a nail or awl to punch a small hole for orienting the bit.
- Set up the drill press with a Forstner bit the same size as the slot you’re cutting. You’ll need to attach a fence to the drill press table to maintain a straight line as you drill along the length.
- Place the blank against the fence and lower the bit. Adjust the fence and blank so the point of the Forstner bit enters the small punched hole. Clamp the fence in place, slide the blank to the mark at the other end of the slot and check that it’s aligned properly.
- Put a mark on the edge of the board that’s against the fence. Keep this edge against the fence when you flip the board over and drill the other side. This ensures the holes are in line even if your a hair off centre of the board.
- Turn on the drill press and drill the each end hole to define the slot – drilling about two-thirds to three-quarters of the way through the board. After that, just keep drilling holes and moving the work piece along the fence, overlapping holes just enough to keep point of the bit entering new wood. The slot will fill up with shavings which you should clear out if they get in the way.
- Once you’ve drilled the length of the slot, clean it out with a screw driver or something similar. Flip the board over (keeping the same edge against the fence).
- Repeat the process starting with the end holes. It doesn’t matter which direction you work in.
A COUPLE OF NOTES:
- If you’re making a wider slot, you may want to make an additional pass to remove the 'peaks' between holes.
- If you have a mortising chisel & bit you could swap that in once you’ve drilled the end holes.
Cleaning up the slot
- After the drilling is complete, clean out the shavings with an awl or small screwdriver.
- Clamp the work piece on edge to your bench and use a flat file to remove the high points left between the drilled holes being careful not to hit the rounded ends of the slots.
- Wrap a small piece of sandpaper around a drill bit (smaller than the slot) to sand the ends of the slot.
- After filing off most of the rough surfaces in the slot, wrap some sandpaper around the file and use it to finish cleaning up the slot.
If the slots were 1/2” wide or more, I probably would have used a jigsaw and straightedge to clean up the slots before sanding.
A wood table top attached with table top fasteners will help to prevent cracking caused by movement from seasonal changes.
Table top fasteners are an easy way to attach a top to a table. But there’s another reason to use figure 8 fasteners, kerf fasteners or DIY table top fasteners. They allow for movement caused by seasonal changes.
A wood table top attached without allowing for movement can cause the wood to crack or split over time. Table top fasteners allow the top to move throughout the seasons. This helps to prevent cracking and ensure your DIY table top will be beautiful for years to come.
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It’s important to have an understanding of wood when building DIY furniture projects. Not just how to cut, and assemble with wood but also to understand how it works. In Mistakes with Wood Can Cause Your DIY Furniture to Crack we talked about how wood is hygroscopic. Simply put, hygroscopic means it absorbs moisture from the air. Seasonal changes cause wood to absorb and release moisture.
This continuous absorption and releasing of moisture causes the wood to swell and shrink. This swelling and shrinking causes the wood to move and this movement causes issues. When it’s more humid, the moisture in the air is absorbed and the wood swells. The swelling actually has enough force to push and pull joints apart. Worse yet, if the wood is joined incorrectly it can cause the wood to crack and split.
One of the most common projects to crack is a wood table top. Many times when building a table the top is attached without taking wood movement into consideration. Recently I received a message from June who wanted to learn more about the correct way to attach a table top:
Thank you so much for this great article! I would love if you could explain more in depth how to attach table tops and add illustrations – I had a hard time visualizing what you meant in your post about your apothecary cabinet and the screws/washers. I don’t have a router or biscuit joiner. Is it a lost cause until I have one of those?”
Thank you so much for reaching out and for the questions. I love hearing from you guys! And yes, absolutely let’s look more closely at some ways to properly attach a wood table top. Oh, and if you have a question you can contact me here.
What Causes a Wood Table Top to Crack?
Before we look at the correct way to attach a wood table top let’s look at the incorrect way to attach a table top. I’m guilty of incorrectly attaching a table top when building a table or even a stool. In my stool project, I drilled pocket holes through the apron, then used pocket screws to attach the stool top.
First, let me say I LOVE pocket hole joinery! I have an entire directory dedicated to Kreg Jig Tips and Tricks and there’s even a page where you can ask your pocket hole questions. But pocket hole joinery is not the best solution to attach a table top.
Using pocket holes to attach the stool base to the stool top prevents the top from moving during seasonal changes. It’s also not a good idea to drive screws through the edge of the apron into the table top. Over time the top could crack or the top could have enough force to push or pull the joints of the base apart. Skate over to Mistakes with Wood Can Cause Your DIY Furniture to Crack to see more about how I incorrectly attached the top on the stool.
Table Top Fasteners Prevent Cracking
A better option for attaching a table top when building a table is to use either store-bought table top fastener or DIY table top fasteners. Table top fasteners securely attaches a table top to a base but allows the top to move freely during seasonal changes.
Figure 8 Table Top Fasteners
One of the easiest options for attaching a table top to a furniture project is with a figure 8 fastener. A Forstner bit is used to drill holes in the apron and the figure 8 fastener is screwed to the apron. The top is then placed on the DIY table and the top is attached with screws through the figure 8 fastener.
Need help installing figure 8 fasteners? My friend Vineta at The Handyman’s Daughter has you covered! Check out her step by step tutorial that explains exactly how to install a table top using these fasteners.
Kerf Table Top Fasteners
Another option for attaching a table top to a furniture project is with a kerf fastener. With this option a groove is cut in the apron using the kerf or width of a table saw blade. Then the table top fastener is inserted into the groove and attached to the table top with a screw.
DIY Table Top Fasteners
You can make your own DIY table top fasteners using scrap wood and a plate joiner or biscuit joiner. For this example, I used “0” biscuits. “0” biscuits are about 2” long.
The DIY fasteners need to be wider than the biscuit, so I made marks every 2-1/2” on a scrap piece of 1×2. Then drew lines using a Kreg Multi-Mark to make sections.
I placed the board on the Kreg Mobile Project Center and against the bench dogs. I used the biscuit joiner to cut slots in the middle of each section.
Using a miter saw I cut the sections apart. It’s not critical that the DIY fasteners are the same width, so just use the lines you drew as a guide for cutting.
Use a countersink bit to drill a hole in each DIY fastener. Make sure not to drill through the biscuit slot.
Next, cut biscuit slots around the inside edge of the apron.
Place the apron on the table top, insert a biscuit and slide the DIY fastener over the biscuit. Do not apply glue to the biscuit. The biscuit is what allows the table top to move during seasonal changes. Attach the fastener with a wood screw.
How to Attach Tabletop with Screws
If it isn’t feasible to attach your table top to the base by the aprons you can do what I did for the wine cabinet and apothecary cabinet. I drilled oversized holes in the top braces.
Cut A Slot In Wood
Then attached the table top to the base with washers and screws. The oversized holes allow the top to move freely and the washers keep the screws from falling into the holes.
Final Thoughts
Attaching a wood table top without allowing for movement due to seasonal changes can cause the wood to crack over time. The best way to attach a table top is with table top fasteners. The fasteners allow the top to move throughout the seasons, help to prevent cracking and ensure your DIY table top will be beautiful for years to come.
Thank you for stopping by. If you found this information helpful, would you please pin it to Pinterest? Other DIYers would appreciate it and I would too! Thank you – Scott