The most recent releases of the Microvellum Foundation Library (library version 23.0609 onward) have made a few noteworthy changes to the available settings of dowels and screw patterns. This article and video were created to document those changes, as well as offer Microvellum clients a brief overview of the settings for dowels and screws within Toolbox.
Available Settings
Figure 1: Default Dado & Screw setting.By default, the library is opened with the Dado & Screw method selected. To change this, open the "Project Specification Group" setting under "Toolbox Setup", then hover over the "Default Construction Method" option, and select Dowel to start, then scroll down to Dowel/Screw.
All machining types with a pattern (dowels, screws, cams, invisible fasteners) have two styles to choose from, Auto Spacing and Custom Spacing. Users can change this setting either at the cabinet level or in the global.
Figure 2: Dowel distance using auto spacing.Auto Spacing is the default and is intended to be the simpler option with less setup. It uses a special MV spreadsheet function called CONSTHOLESPACING that calculates the delimited list of hole locations. This spacing will always place the first and last hole at a designated space and equal out the remaining holes in-between. It uses a “target spacing” value to approximate the distance between those center holes. Since it will always equal out the spacing, the distance between the middle holes will never be the exact target spacing value, unless the size of the part happens to match up exactly. This method works well for patterns that need to remain symmetrical for parts that need to be flipped and still align.
Figure 3: Dowel distance using custom spacing.Custom Spacing is the second option and intended to be used when Auto Spacing cannot achieve one's desired pattern. Instead of a local function at the part level, it utilizes a LookUpTable inside the global variable workbook. This table lists out each part size, hole location, target spacing, and finish- allowing users to set nearly any pattern desired in terms of measurement. While users are able to input any custom measurement into the table this way, the general default formula within the LookUpTable is 16mm of spacing (32mm in versions prior to 23.0609).
Dowel & Screw Variables
Figure 6: Dowel and Screw collision.The settings for Screws and Dowels are best left on a single setting across the board: either autospace or customspace. If using both, users run the risk of causing overlap and collisions within the machining if both are turned on simultaneously, because if the total distance (absolute value of the end offset minus the start offset->rounded to the 5th decimal place) is less than the target spacing times two, but greater than the target spacing times one, a single midpoint is placed that is equal to the start offset plus the difference of the total distance divided by two. Based on the function parameters, two tokens can end up having the same midpoint.
The recommendation in this circumstance would be to keep the dowel offset at zero and set the screw offset at something like 32mm.