making a jig

This forum is for general discussion regarding VCarve Pro
Post Reply
jlroch
Posts: 10
Joined: Fri Aug 06, 2021 8:48 pm
Model of CNC Machine: generic

making a jig

Post by jlroch »

hello

i want to create a jig as follows: (see attachment)

using a 1/8 end mill, i will cut inside the line to remove the material from inside each rectangle. this will leave rounded corners in each rectangle.


using the same pattern as above (from a second piece of material)i will cut outside the line on the same rectangles to create blocks which will then be inserted into the jig for machining. cutting on the outside will leave square corners. when i attempt to insert the blocks into the jig, they will not fit as the hole has rounded corners.

how do i fix this?
Attachments
jig.pdf
(16.29 KiB) Downloaded 123 times

Charlie_l
Vectric Craftsman
Posts: 182
Joined: Sat Jun 30, 2012 1:41 am
Model of CNC Machine: CAMaster Stinger II
Location: Wisconsin

Re: making a jig

Post by Charlie_l »

Does your software have a tool for creating a dogbone fillet? If not, you can add some circles on the corners larger than your bit diameter and create a larger circular corner.
Charlie
Aspire, CAMaster Stinger II

User avatar
dealguy11
Vectric Wizard
Posts: 2464
Joined: Tue Sep 22, 2009 9:52 pm
Model of CNC Machine: Anderson Selexx 510
Location: Henryville, PA

Re: making a jig

Post by dealguy11 »

Either a t-bone or dog bone fillet on the corners will solve the problem. I usually use t-bone for this, but it doesn't really matter. Make sure the radius of the fillet is 1/16" or larger (i.e., at least the radius of the end mill)
Steve Godding
Not all who wander (or wonder) are lost

User avatar
martin54
Vectric Archimage
Posts: 7339
Joined: Fri Nov 09, 2012 2:12 pm
Model of CNC Machine: Gerber 48, Triac PC, Isel fixed gantry
Location: Kirkcaldy, Scotland

Re: making a jig

Post by martin54 »

Do the blocks have to have square corners? If rounded corners would work ok on your blocks then you can use the inlay loolpath to create both the male & female parts, the inlay toolpath is designed to overcome this sort of problem.
If the blocks need to have square corners then use fillets as has already been said. :lol: :lol:

For my jigs where square internal corners are required I just took the corners out with a chisel I could have used fillets but it's not a big job to take them out by hand if you use a small bit for the profile :lol:

jlroch
Posts: 10
Joined: Fri Aug 06, 2021 8:48 pm
Model of CNC Machine: generic

Re: making a jig

Post by jlroch »

thank you all!!!
the dogbone filet is doing the trick.

jlroch
Posts: 10
Joined: Fri Aug 06, 2021 8:48 pm
Model of CNC Machine: generic

Re: making a jig

Post by jlroch »

woke up in the middle of the night thinking about the bench tutorial.
at one point, it is suggested to make dogbone filet for the mortise on the seat so as to deal with the "rounded corners" issue.
when the tenon is pushed into the mortise, won't the rounded corners leave a gap between the tenon and mortise at each corner?

User avatar
adze_cnc
Vectric Wizard
Posts: 4327
Joined: Sat Jul 27, 2013 10:08 pm
Model of CNC Machine: AXYZ 4008
Location: Vancouver, BC, Canada

Re: making a jig

Post by adze_cnc »

jlroch wrote:
Thu Dec 02, 2021 4:32 pm
won't the rounded corners leave a gap between the tenon and mortise at each corner?
Yup. Call it the "CNC Aesthetic"...

User avatar
dealguy11
Vectric Wizard
Posts: 2464
Joined: Tue Sep 22, 2009 9:52 pm
Model of CNC Machine: Anderson Selexx 510
Location: Henryville, PA

Re: making a jig

Post by dealguy11 »

If you're just looking to make a jig, then that space doesn't matter.
Steve Godding
Not all who wander (or wonder) are lost

jlroch
Posts: 10
Joined: Fri Aug 06, 2021 8:48 pm
Model of CNC Machine: generic

Re: making a jig

Post by jlroch »

absolutely!
but what if i were making the bench in the demo....

User avatar
Adrian
Vectric Archimage
Posts: 14544
Joined: Thu Nov 23, 2006 2:19 pm
Model of CNC Machine: ShopBot PRS Alpha 96x48
Location: Surrey, UK

Re: making a jig

Post by Adrian »

jlroch wrote:
Thu Dec 02, 2021 8:09 pm
absolutely!
but what if i were making the bench in the demo....
That's just the way it is with a round tool. If you want to do everything on the CNC then you have to have a dogbone or cut everything with radii to match which isn't always possible.

As said earlier in the thread sometimes a simple chisel is the best solution.

User avatar
martin54
Vectric Archimage
Posts: 7339
Joined: Fri Nov 09, 2012 2:12 pm
Model of CNC Machine: Gerber 48, Triac PC, Isel fixed gantry
Location: Kirkcaldy, Scotland

Re: making a jig

Post by martin54 »

For me the CNC is just another piece of machinery in the workshop, lots of jobs are still quicker/easier to do with other tools, don't fall into the trap of trying to do everything with the CNC, it's an easy trap to fall into when you first get a machine :lol: :lol: :lol:

User avatar
TReischl
Vectric Wizard
Posts: 4596
Joined: Thu Jan 18, 2007 6:04 pm
Model of CNC Machine: 8020 48X36X7 RP 2022 UCCNC Screenset
Location: Leland NC

Re: making a jig

Post by TReischl »

Who says a tenon has to have a square corner anyhow?

I cut mine on the front of the machine with the piece standing vertically. The worksurface on the machine is 39 inches from the floor. So I can cut pretty much any tenon I need to. BTW, I love doing it this way. Once the tenon is dialed in (yanno, tool bit diameter, etc) I can cut perfect fitting tenons all day. Since it is side cutting the cuts are really nice.

And, failing that! Round the corners over with a file. Who'd a thunk?

Pays to avoid the ol' "When all you have is a hammer everything looks like a nail" syndrome.

Edit: Martin already said that!!!!
"If you see a good fight, get in it." Dr. Vernon Johns

jlroch
Posts: 10
Joined: Fri Aug 06, 2021 8:48 pm
Model of CNC Machine: generic

Re: making a jig

Post by jlroch »

i was actually thinking the same thing. cut at the vertical!

User avatar
TReischl
Vectric Wizard
Posts: 4596
Joined: Thu Jan 18, 2007 6:04 pm
Model of CNC Machine: 8020 48X36X7 RP 2022 UCCNC Screenset
Location: Leland NC

Re: making a jig

Post by TReischl »

Here is a link to my YouTube video showing the fixture I use:

https://youtu.be/NhLkB1ZyOPo

Cutting finger joints in the video, but it is the same principal. Tenons are easier.

There is quite a bit of air cutting in the video because I was rolling the tool around the corners of the tenons to prevent chipout, that is what those first two cuts are doing, getting rid of material that could chip out.
"If you see a good fight, get in it." Dr. Vernon Johns

User avatar
scotttarnor
Vectric Wizard
Posts: 941
Joined: Fri Aug 30, 2019 11:40 pm
Model of CNC Machine: Piranha XL , Shark HD520
Location: La Crosse WI

Re: making a jig

Post by scotttarnor »

TReischl, Nice video have to remember the first cuts to prevent blow out :idea:
You scared me with the collet getting close to the material in the final pass.
Scott T

@scottscnc

Post Reply