T-Slot Wood Clamps for my CNC

Four clamps conspiring

This is not a new design of mine.  I've been using these wood clamps for several years.  They are sacrificial though and many have encountered spinning router bits during their lives. 

A few of the scrap wood blocks in my collection have hinted that they'd like to be clamps. As such this post is about granting that desire and replacing some previous clamps that are near death. 

My previous clamps were cut from larger boards,  A few were cut as two halves that I glued together.  A few were cut from thicker boards, then turned 90 degrees so I could cut the slot for the bolt in them.  

The length of these clamps is not critical to their usefulness and can vary. 

The first one (upper right)  I made from a dense white oak scrap.  It suffered a few broke out chips when the bottom edge was flush cut after the CNC was done. It works despite those missing bits. 

The second clamp I cut from a scrap of birch (lower left).  It also gave me some grief as I made a mistake when clamping the scrap block down. I stopped the CNC after the first pass when I realized that mistake.  It works but has a few scars from my bandsaw, drum, sand disk sanders.

The last two clamps were cut from a 5/8" thick scrap of walnut. Room enough for 4 halves that when glued together made two clamps. I added an alignment hole for a 3/4" long section of 1/4"diameter wood dowel to make it easier to clamp the halves together and aligned. 

One Scrap, Four clamp halves

Making them in halves is the most reliable method. Especially if you don't have an easy way to cut the slot after cutting out the clamp profile from the side. 

Here are two made from one block of white ash.  Both cut out as one piece, then turned sideways to cut the slots in them. 

Short Ash Clamp

Long Ash Clamp

These clamps hold the work down and also prevent it from moving sideways.  Made from wood you don't have to worry if a router bit accidently encounters one. Should one or more  be ruined from such an encounters making replacements is easy. 

4D 

Updated Wrench Handle for my Bench Vise

New handle.  Teak Oil Finish.

While there is nothing fundamentally wrong with the plywood handle I made for my garage bench vise, there are a couple of changes that could make it more useful. 

Plywood Handle

The first issue it that the handle extends above the top of the vise when vertical, and has occasionally been limited in use by objects I wants to clamp down that hang over the edge. The second issue is that it doesn't slip off easily.  If it did I could easily overcome the first issue by sliding it off and rotating it 60 or 120 degrees before slipping it back on.   I do this with the wrench handle I made for my CNC low profile vise. 

First thing needed was a CNC file and a piece of wood to make the new handle from.

Render from my Aspire software.

The wood used was a heavy and dense block of white oak.  The nut pocket, shaft hole, end hole, rounded off edges, and perimeter outline were all cut using my CNC.  The bottom side details were finished on my trim router table.  Holes for the pivot pin were drilled out on my drill press. 

When flat the new handle is the same length as the old one. The hinge allows folding the new one out to clear anything hanging over the edge of the vise.

Handle folds out.

This handle was eventually sealed with teak oil to protect the wood. It slides on and slips off easily but stays in place otherwise. 

Iteration is always a worthwhile endeavor.  The initial wrench handle worked, but use of it revealed the flaws that needed fixing.  Should the new handle reveal any new insufficiency a 3rd iteration may be needed.   Time will tell. 

4D

Compartmented Box for M6 Screw Assortment

I needed some flat head M6 screws for a project, and they came in a cheap subdivided plastic box. Sizes vary from 6mm to 22mm long.  The shiny stainless steel screws looked to me like they deserved a nicer box. This compartmented walnut box was made to hold them. 

Compartmented Box

The lid for the box slips onto the box easy and wedges down securely with a 3 degree tapered edge.  While I do have another piece of walnut that I could use for the top, a scrap of salvaged weathered wood with more interesting grain challenged that presumption. It was thick enough that a second use was cut into the top of it. 

Lid from a Weathered Wood Scrap

It now is a shallow tray to coral whatever small parts my current project may need. 

Parts Tray

A simple project.  Pocket toolpaths for the inner compartments. A profile toolpath for the perimeter. Another pocket for the rabbet edge on the underside of the lid.  Another profile toolpath for the outer shape of the lid.  Then the lid was flipped over to pocket cut the recess center of the tray, and round the inner edge of the recess using a profile on-the-line with a 3/8"d ball end bit.  

Comments encouraged!

4D

Nesting Boxes.

 As my collection of wood scraps vary in length, width, and thickness, it occurred to me that a series of boxes that nest together might be a fun project to make.  Open the largest one to find a slightly smaller one inside.  Open that box to find an even smaller box inside it. Open that smallest box and there may be a surprise to find inside it. 

This story is not yet complete, but it starts with one box.

One Box. 2.625" x 1.75" x 1.5: tall.

Open the lid to find the lid of another smaller box.

Something inside.

Remove it to discover that lid covers another box.

Box #2. 2.25"x 1.375" x 1" tall.

Open the lid of box #2....

To find Box #3.

Box #3 is missing a lid.  The lid will have a dovetailed edge that slides in from the side.  That lid is yet to come. 

Three nesting boxes. 

With a range of router bits available, and a range of scraps in varying thicknesses available, CNC cut boxes can be made in a range of sizes.  The smallest box is 1.75" x 15/16" x 7/16" thick. It was cut with a 1/8" diameter bit.  An even smaller box may come, as I do have a 1/16" diameter bit.  Larger purely CNC cut boxes are limited by the length of the available bits and the Z axis range of my CNC. A constructed box with 4 sides, a bottom, and a lid may yet encase these nested CNC cut boxes.  Time and the available wood scraps I have will tell. 

4D

  

Table Saw Throat Plate Fix

My table saw's throat plate is unsupported at the end next to the blade slot. It will flex down when I'm cutting thin strip and cause them to catch on the lip of the table top. This is a solution for that design flaw.

Throat plate unsupported here.

Three inches or so below that area is the top edge of the blade housing. I carefully measured how thick the housing was, how far it was below the table saw bed, and how thick the throat plate was at that spot.

1" Dowel to Support the Throat Plate

I cut a slot in the bottom end of a 1" dowel to slip snuggly over the blade housing.  The dowel now stands up to support the throat plate. 

A simple solution for a nasty design flaw.  I only wish I'd gotten around to solving this 10 years ago. 

4D

 

A Small Maple Box with a Contoured Lid.

This little box was cut from 4 corner scraps left over from a previous project.  The 4 corners were glued together to make a board with enough area for this 3" x 3" box. 

The lid was made from a scrap of Walnut wood I found in my scrap bin. The walnut was a bit thicker than I liked, so I cut the top to taper down to a thinner edge. 

Contoured Top

The bottom has a rabbet edge with a 3 degree slope for a fit that slips on easy but wedges tight.

Rabbeted edge

The lid overhangs the box by 1/16" to make it easier to pop the lid off. 

Overhanging Edge

The contrast between lid and box wasn't my original intent.  I started with a scrap of beech for the top but it worked loose while being cut and was ruined. A constant potential of using the CNC for making small parts.  I may darken the box with a walnut stain to lessen the contrast between box and lid. 

4D

 

Low Angle Dovetail Joint

I found this joint sample hiding in a box of CNC-cut joinery samples I made for students to consider when designing their project. 

For Low Angle Corners

One half slides into the other half.

Not quite as simple as it looks to cut

I endeavored to figure out how to connect wood pieces at any angle with a CNC-cut joint while I was teaching.  This is an extreme sample that I don't remember ever using for a student project.  The left half in the photo above is the complicated one to cut.  The sides taper in as the bottom of the dovetail is narrower than the top.  

This sample will return to the box I found it in to wait hopefully for the day when it can come out to inspire a real corner connection on an actual project. 

4D 

T-Square/Marking Gauge Add-On for a Small Ruler

Not all projects take a lot of time or a lot of wood.  A little scrap of Bubinga that was headed for the trash bin turned out to be the perfect material scrap for this project. 

Bubinga Scrap

Three CNC toolpaths.  Three vectors. Two router bits.  The slot that the ruler slides into was cut with a 1/8" t-slot bit.  The center area and curved edge were cut with the same 3/16" spiral down-cut end mill.  The blue friction tape keeps the ruler in place but still lets it slide out easy for compact storage. 

T-Square

This little block of wood turns a simple cheap ruler into a slightly more useful T-Square.  I plan to add this ruler/T-square to a drawing kit box project.  

A bonus feature is that the ruler can slide through.  This allows it to work as a marking gauge.

Marking Gauge

To insure that the ruler won't slide when using it I cut a recess under the friction tape for a small square nut, and added a thumb screw to lock the ruler in place.

Thumb Screw to lock it in place. 

 I'm delighted with how well it works and easy it was to make.  The bubinga scrap is delighted to be something useful.   😊

4D

 

A Pencil Case. CNC Cut.

 A member of a router forum suggested I look into making a pencil box. 

A Pencil Shaped Box

As I designed the pencil shaped box I pondered what it might hold.  I concluded that a pencil box would most obviously hold a pencil.

Splits open to access a #2 pencil

This project though has provoke my runaway imagination to design a box that would hold much more. 

A pencil case at minimum only has to hold a single pencil.  I started out with a simple pencil shaped case that holds one pencil.  The hexagram body of the case was easy.  The conical tip was the challenge.  Sharpening the end of the case proved to be a challenge.  Half of a tapered cone cut from each side is what was needed. I figured out how to model the half cone, but not how to cut it.  I had to wait until both sides were done then clamped them together and vertically to use the moulding toolpath to cut the cone end. 

Alignment to the Y axis of my CNC for long skinny projects like this is a persistent challenge. Using my low profile vise to hold the first half of this single pencil case I took care to align the vise and board before cutting it. The vise was clamped down and not moved for the second half but clearly that was a mistake. The second half was slightly mis-aligned on one end.  Some sanding and a little trim router use cleaned up the mis-aligned edges.  

Many of these box projects have been excellent lessons on dealing with small projects and the precision needed.  Well worth the time.  Well worth the experience provided. 

4D

Red Zebra Wood Box with a Slide -in Lid

Poplar Lid

Mistakes are easy to make if you don't pay attention. This little Red Zebra Wood box with a Poplar slide-on lid looks fine, but the grain orientation of the lid should have been the same as the grain orientation of the box.  As such there will eventually be another lid for this box. 

The slot for the lid to slide into was cut with a t-slot bit. 

Lid Off.

The fit is good, but as wood likes to expand or contract across the grain when humidity changes I can't trust that the fit will always be the same. 

Slides in easily.

The red zebra wood block was dense and heavy.  It cut clean and nice.  The Poplar lid also cut nicely but wanted to split out on the edges. Toolpaths needed were simple to create.  The same vectors were used for both the box and the lid.  A small .003" allowance was used for the lid toolpaths so they wouldn't be too tight to slide in easily.

Alas I couldn't quit until the box had a new lid with the grain running left to right rather than up and down the lid.   Here is the box with a lid made from Ash wood. 

New Ash Lid.

Comments encouraged!

4D  

Walnut Box with a Hinged Lid

  I've had this block of Claro Walnut in my stash for a month or so. Recently it dared me to make something from it. 

Rough Block in Vise

It took a few steps to turn this block into a hinged box.  First step was to cut out the inside and then the outer edge using a 1/4" end mill. 

Inside and Outer Edge Done

Next step was to use a 3/16" end mill to cut slots for a hinge plate near each end. 

Hinge Slots Cut

The last step using the CNC was to round over the back edge using a 3/16" ball nosed bit. 

Rounded Back Edge

While in the vise I couldn't cut the bottom 1/2" of the perimeter so the box moved over to my trim router table to be flush cut.

Ready to Flush Cut

The flush cut bit struggled cutting the end grain sides and left some sanding to be done to even out the surface.

Flush Cut. Some Sanding Needed.

A lid and hinges were still needed.  For the lid I found an old strip of 3/4" thick walnut.  I cut off 10" or so, then ripped it  2" wide using my table saw. Next I used my bandsaw to slice it in half.   I took one half and ran it through my drum sander to sand it smooth and uniformly thick.  That strip was cut into 3 pieces, which I then glued together side by side.  This left me with a thin piece large enough to cut the lid from. 

Lid.  CNC Done

Next came the band saw to free the shape from the rough block.

Bandsaw to free the lid.

Then to my trim router table to clean up the edges. 

Flush Cut the Edges

Now trimmed close to the shape of the box, and waiting for hinge plate inserts.

Slots align.

Hinge plates are cut from 6mm thick Baltic Birch plywood.  Glued into the slots in the lid. Pinned into the box with 1/8"d steel pins.

Lid Attached

The lid opens 90 degrees but no more. Action is smooth but I may test if a little wax on the hinge plate makes a difference. 

Lid closed.

All machining processes done.   Some manual sanding and a final coat of finish or two or three is all that is left to do.   A fun project. A good mental exercise. A useful box. Fewer wood scraps to deal with.  4 wins!

Comments encouraged!

4D 





 

Cherry Box with a Slide-On Lid

I'm trying to master every kind of lid that a small box could have.  So far I've mastered simple drop on lids, a swivel lid, and hinged lids.   This little cherry box has a maple lid that slides on.  An undercut dovetail edge keeps it in place.  

CNC is done with the box.

Two pocket cuts were needed as well as one profile pass to make the box.  The center area and the front edge were pocket cuts.  The dovetailed undercut was a profile on-the-line pass.

Making the lid was the biggest challenge as all sides of it needed to be cut from a block barely larger than the final lid shape.  I split the dovetail undercut side and back edges into two paths, one for the right side and one for the left side.  That way I could clamp down the side that wasn't being cut.   I also was able to check the fit into the box while the lid was still clamped to the CNC.  Two minor .005" resets of the X axis and recuts of both sides crept up on a very good fit. 

A nice slip fit.

The dovetail undercut worked very well, although it took some careful toolpath creation for both the box and lid to fit so well.  Knowing the diameter and slope of the dovetail bit at different depths is the key.  Some drafting required. 

Half way open.

I also like the contrast between the maple lid and the cherry box. Grain alignment of both should eliminate any threat of the fit changing with humidity changes. 

Just Two Parts.

Before this box existed the wood used was just two scrap cutoffs from other larger projects.  I've always resisted throwing out cutoff ends if they were of a good hardwood.  Wood pieces with flaws or splits often have an undamaged section that could be used, if only there was a project for small pieces.   These little boxes are that project. 

Comments encourage!

4D