# Margins for Tab & Slot Construction? **URL:** \ **Category:** Technical Details\ **Created:** [June 16, 2024, 12:04am UTC](https://forums.maslowcnc.com/t/margins-for-tab-slot-construction/21544 "2024-06-16T00:04:13Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![jwolter](https://yyz1.discourse-cdn.com/flex031/user_avatar/forums.maslowcnc.com/jwolter/32/30787_2.png) [@jwolter](https://forums.maslowcnc.com/u/jwolter)\ **Post date:** [June 16, 2024, 12:04am UTC](https://forums.maslowcnc.com/t/margins-for-tab-slot-construction/21544/1 "2024-06-16T00:04:13Z")
My next project is a very shallow ramp for a cabinet over a refrigerator in an RV. The ramp will (hopefully) provide just enough inducement to the items stored in the cabinet to not wander to the back of the cabinet where we can’t reach them. There’s a lip at the front of the cabinet to keep things from pressing against the cabinet door and popping it open. I have already realized that I should probably add dogbones to the corners of the slots and tabs so I don’t have to spend extra time with a chisel or saw squaring my holes (see [Tab and slot corners](https://forums.maslowcnc.com/t/tab-and-slot-corners/2463) if you don’t know what I’m talking about here) ![RampOverFridge](https://canada1.discourse-cdn.com/flex031/uploads/maslowcnc/original/3X/5/3/5387e1a73332cee60517772259c3d26fdbb6334a.png) My question is how much margin should I add to the slots so I can get the tabs to go in? My board is 0.25" MDF, which tends to be very consistent thickness, but I assume that if I make my slots exactly 0.25" wide, I will have trouble getting the tabs to go into the slots. ---
**Author:** ![md8n](https://yyz1.discourse-cdn.com/flex031/user_avatar/forums.maslowcnc.com/md8n/32/28197_2.png) [@md8n](https://forums.maslowcnc.com/u/md8n)\ **Post date:** [June 16, 2024, 12:12am UTC](https://forums.maslowcnc.com/t/margins-for-tab-slot-construction/21544/2 "2024-06-16T00:12:35Z")
My answer would be to do a smaller test project to get the numbers that you need. Because I’m going to guess that each person’s M4 will do things slightly differently. ---
**Author:** ![jwolter](https://yyz1.discourse-cdn.com/flex031/user_avatar/forums.maslowcnc.com/jwolter/32/30787_2.png) [@jwolter](https://forums.maslowcnc.com/u/jwolter)\ **Post date:** [June 16, 2024, 12:14am UTC](https://forums.maslowcnc.com/t/margins-for-tab-slot-construction/21544/3 "2024-06-16T00:14:36Z")
I was afraid that was the answer. Not that that is hard, just slows me down from cutting my part. 😆 ---
**Author:** ![jwolter](https://yyz1.discourse-cdn.com/flex031/user_avatar/forums.maslowcnc.com/jwolter/32/30787_2.png) [@jwolter](https://forums.maslowcnc.com/u/jwolter)\ **Post date:** [June 16, 2024, 1:10am UTC](https://forums.maslowcnc.com/t/margins-for-tab-slot-construction/21544/4 "2024-06-16T01:10:24Z")
Here’s an OnShape design for a tester. [Onshape](https://cad.onshape.com/documents/0cd35d6b7666c1fec0e47bde/w/97d59c91ae286f1a0f71712b/e/6932723371f43f9e99b1bba1) ![SlotTester](https://canada1.discourse-cdn.com/flex031/uploads/maslowcnc/original/3X/2/2/229bca90fca65757ffaf12f22579175a1152ba4c.png) ---
**Author:** ![bar](https://yyz1.discourse-cdn.com/flex031/user_avatar/forums.maslowcnc.com/bar/32/10_2.png) [@bar](https://forums.maslowcnc.com/u/bar)\ **Post date:** [June 17, 2024, 6:20pm UTC](https://forums.maslowcnc.com/t/margins-for-tab-slot-construction/21544/5 "2024-06-17T18:20:31Z")
Check out this onshape plugin to add the dogbone shape to your cuts supper fast > **[Dogbone and Corner Overcut Features for CNC router design](https://forum.onshape.com/discussion/4150/dogbone-and-corner-overcut-features-for-cnc-router-design)** > > A lot of my parts need to be cut out on a CNC router where the spinning bits cannot cut sharp internal corners. ---
**Author:** ![jwolter](https://yyz1.discourse-cdn.com/flex031/user_avatar/forums.maslowcnc.com/jwolter/32/30787_2.png) [@jwolter](https://forums.maslowcnc.com/u/jwolter)\ **Post date:** [June 17, 2024, 6:44pm UTC](https://forums.maslowcnc.com/t/margins-for-tab-slot-construction/21544/6 "2024-06-17T18:44:18Z")
That’s great! I used to use OnShape a lot and then stopped doing much CAD on any platform. So I’m very out-of-date regarding features and add-ons. I’ll have to learn how to use FeatureScript (or at least how to use someone else’s FeatureScript on my designs). ---
**Author:** ![dlang](https://yyz1.discourse-cdn.com/flex031/user_avatar/forums.maslowcnc.com/dlang/32/859_2.png) [@dlang](https://forums.maslowcnc.com/u/dlang)\ **Post date:** [June 17, 2024, 9:31pm UTC](https://forums.maslowcnc.com/t/margins-for-tab-slot-construction/21544/7 "2024-06-17T21:31:25Z")
Bar wrote: > Check out this onshape plugin to add the dogbone shape to your cuts supper fast > > [Dogbone and Corner Overcut Features for CNC router design — Onshape](https://forum.onshape.com/discussion/4150/dogbone-and-corner-overcut-features-for-cnc-router-design) I especially like the corner overcut that only cuts as much as needed for your other part to fit rather than doing a full half-bit past the corner. David Lang ---
**Author:** ![dlang](https://yyz1.discourse-cdn.com/flex031/user_avatar/forums.maslowcnc.com/dlang/32/859_2.png) [@dlang](https://forums.maslowcnc.com/u/dlang)\ **Post date:** [June 17, 2024, 9:32pm UTC](https://forums.maslowcnc.com/t/margins-for-tab-slot-construction/21544/8 "2024-06-17T21:32:21Z")
John Wolter wrote: > That’s great! I used to use OnShape a lot and then stopped doing much CAD on > any platform. So I’m very out-of-date regarding features and add-ons. I’ll > have to learn how to use FeatureScript (or at least how to use someone else’s > FeatureScript on my designs). right click on it and you can then add it to your toolbar and use it like any other feature. David Lang