Fingers

Finger joints are a bit of art and a bit of science.

The science part is the math: GCrafter uses the size of an edge and the finger settings to create interlocking tabs and slots. The art part is that not every combination looks good, fits well, or leaves enough material at every corner. Sometimes the numbers technically work, but the corner geometry gets crowded. What used to be a clean corner can disappear after several intersections all try to share the same space.

That is normal. Finger settings often need a little tuning.

Finger Count vs. Finger Size

For each project item, you can set finger values for:

• Width
• Length
• Height

These values are related to the item’s dimensions.

You can work with fingers in two ways:

1. By count
   Choose how many fingers should fit across an edge.

2. By size
   Choose the actual size of each finger.

The toggle button lets you switch between these two views.

How Counts Become Dimensions

When you enter a finger count, GCrafter calculates the actual finger size needed to fit that count across the selected dimension.

For example, if an edge is:

300mm

And the finger count is:

5

GCrafter may calculate a finger size of:

33.33333mm

So even though you entered a count, there is still a real measurement behind it.

How Dimensions Become Counts

You can also switch to finger size and enter the exact dimension you want.

For example, maybe GCrafter calculates:

33.33333mm

But you want cleaner numbers, so you enter:

30mm

That changes the finger size directly, and GCrafter updates the count that fits across that edge.

So the relationship works both ways:

Finger count → calculates finger size Finger size → updates finger count

They are two views of the same underlying relationship.

Why the Numbers May Need Adjusting

Finger joints are created where parts intersect. On a simple box, this usually means several edges and corners are all trying to work together.

Most of the time, this is exactly what you want.

But some combinations can create awkward corners, especially when fingers from multiple directions meet in the same area. If the spacing is too even, too crowded, or just unlucky, the resulting cuts may remove more material than expected.

That can lead to:

• Broken-looking corners
• Missing corner material
• Tiny slivers
• Odd intersections
• Fingers that do not look balanced
• Joints that technically generate, but are not ideal to cut

This does not mean the design is broken. It usually means the finger spacing needs a small adjustment.

Example: When 5 × 5 × 5 Is Not the Answer

A clean, symmetrical setup sounds nice:

Width: 5 Length: 5 Height: 5

But depending on the item size, material thickness, and how the parts meet, that may not create the best corners.

Sometimes changing just one axis is enough:

Width: 5 Length: 5 Height: 4.5

That small change can move the finger pattern away from a problem area and produce a cleaner corner.

It may also look better.

This is where the art comes in.

A Practical Way to Tune Fingers

Start with a simple count that seems reasonable for the size of the object.

Then check the corners.

If something looks wrong, try adjusting one axis at a time:

1. Change the width finger count slightly.
2. Check the corners.
3. Change the length finger count slightly.
4. Check again.
5. Adjust height if needed.

Small changes can make a big difference.

You do not always need whole numbers, either. A value like 4.5 may solve a corner problem better than 4 or 5.

When to Use Finger Size Instead

Use finger size when you care about the actual measurement of each finger.

For example, you might want:

• Exactly 30mm fingers
• A finger size that matches a design detail
• A size that works better with your bit, laser kerf, or material
• Cleaner numbers for documentation or repeatability

Switch to the dimension view, enter the finger size you want, and let GCrafter calculate the resulting count.

Short Fingers

Short fingers control what happens when a finger pattern does not divide perfectly across an intersection.

Options are:

• True
• False

Short fingers are partial fingers that appear at the beginning and end of an intersection. They may be half fingers, quarter fingers, or another partial size depending on the spacing.

For example, a finger count of:

5.5

with short fingers enabled may create:

5 full fingers

plus partial fingers at the start and end.

Use short fingers when you want the pattern to fill the available intersection more evenly.

Center

By default, fingers are computed from the project item center.

This helps multiple parts along the same axis maintain consistent spacing. If several parts share a direction, their fingers can line up according to the larger project item instead of each part inventing its own pattern.

That is usually helpful.

However, if a part is smaller, moved to a precise position, or being used for a more custom purpose, you may want the finger spacing centered on that part or intersection instead.

Use Center when the inherited spacing no longer feels appropriate for the specific part.

Repair

Repair can be set to:

• True
• False

Repair tells GCrafter to try to fix broken or awkward corners caused by finger intersections.

The key word is try.

Some corner problems can be repaired automatically. Others are too specific, too crowded, or too weird for an automatic fix to solve cleanly.

If repair does not solve the issue, you can often address it later by adding a filler shape or custom adjustment in PartLab.

The Main Idea

Finger count and finger size are connected.

Changing one affects the other.

A count is not just a count—it becomes a real dimension. A dimension is not just a dimension—it determines how many fingers can fit.

So if the first result does not look right, adjust it. Try a nearby count. Try an exact size. Change one axis. Check the corners.

That is the normal workflow.

Finger joints are precise, but getting them just right sometimes takes a little taste.