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potential CNC for round sash windows making

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GregW

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Hello,
I wonder if anyone have experience in CNC machines, and how to use them to cut custom size sash frames from half circle made profiles?
 

JobandKnock

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Unless you have a CNC with a scanner and the ability to convert a scanned file to a vector file (e.g DXF) and then a cutting path you may find it difficult. TBH it msy be easier to find someone who can ring fence the job on a spindle or template rout it on an overhead pin router
 

GregW

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Unless you have a CNC with a scanner and the ability to convert a scanned file to a vector file (e.g DXF) and then a cutting path you may find it difficult. TBH it msy be easier to find someone who can ring fence the job on a spindle or template rout it on an overhead pin router
There have to me CNC workshops to do things like that daily. Table tops half circles, with second 14by38mm deep inner rim? 🤔

“Ring fence the job” ?
Like a ring on a moulder router takes forever… and if I need to make 3 of them into to half circle and frames to them, on a perfect half circle…
…hand job of a noob like me will come as a massacre to a entire profession 😵💫 I did short angles, but perfect half circle on a ring…. Well, over my ability.

“template rout it on an overhead pin router”?
Like an piece-arm-distance round motion of a router? Hand router fixed to a wooden-arm one end and pin fix wooden-arm other end?
But than
 

Jacob

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There have to me CNC workshops to do things like that daily. Table tops half circles, with second 14by38mm deep inner rim? 🤔

“Ring fence the job” ?
Like a ring on a moulder router takes forever… and if I need to make 3 of them into to half circle and frames to them, on a perfect half circle…
…hand job of a noob like me will come as a massacre to a entire profession 😵💫 I did short angles, but perfect half circle on a ring…. Well, over my ability.

“template rout it on an overhead pin router”?
Like an piece-arm-distance round motion of a router? Hand router fixed to a wooden-arm one end and pin fix wooden-arm other end?
But than
Spindle moulder with ring fence.
 

GregW

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Spindle moulder with ring fence.
Thanks. Thank you. I’m not sure I’m going to be able to do it 3 perfect half circles on a ring… 😐

If I attempt it this way, how to rotate the piece of wood to keep the same depth of cut?
Should I put a somewhat blockages to keep the same point of contact on the ring…?
Any masters showing the skills on vastness of YouTube you could recommend to see how-to?
 

Jacob

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Thanks. Thank you. I’m not sure I’m going to be able to do it 3 perfect half circles on a ring… 😐

If I attempt it this way, how to rotate the piece of wood to keep the same depth of cut?
Should I put a somewhat blockages to keep the same point of contact on the ring…?
Any masters showing the skills on vastness of YouTube you could recommend to see how-to?
Sounds like you have a bit of a learning curve coming up! Have you got a design for these windows? - thats the starting point.
This the last one I did:

.
bigwin2011.jpg


In the workshop - the half round part of the frame is in two pieces. Cut out with a band saw then the inner face and rebate cut with a spindle moulder and ring fence with the workpiece attached to an exact mdf pattern of the shape.
Outer edge just cleaned up roughly as it would be out of sight.

lw2.jpg
 
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GregW

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Sounds like you have a bit of a learning curve coming up! Have you got a design for these windows? - thats the starting point.
This the last one I did:

.View attachment 117979

In the workshop - the half round part of the frame is in two pieces. Cut out with a band saw then the inner face and rebate cut with a spindle moulder and ring fence with the workpiece attached to an exact mdf pattern of the shape.
Outer edge just cleaned up roughly as it would be out of sight.

View attachment 117980
The start: have design.
I have a size of windows “volume” (size on the brisk work I make a frame too, so that’s is a string is calculating sizes from one to another, dot to dot.
I’m not Abode/CAD trained so I not make any 3D laptop designs. Old school paper and drawings only.


Interesting about the MDF template. Is that to go against the ring?
Looks like just that hint solved some of my mysterious noob problems…. 🤔
 

Jacob

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....

Interesting about the MDF template. Is that to go against the ring?
..
yes. There's lots of variations on how to do it. If you were doing rebate or moulding, the ring could go against the workpiece itself and so on
Ring fence is a bit intimidating at first but once you've got it it can be surprisingly easy
 

Jacob

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.... Old school paper and drawings only.
....
Me too. Much faster and easier that way!
What is the job exactly - not exactly clear from what you've said so far.
 

Ollie78

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As crispy says, make a template on the cnc then use a bearing or ring fence on the spindle.
Failing that make an mdf template with a bit of string a jigsaw and some sandpaper the old fashioned way.

Ollie
 

whereistheceilidh

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Sounds like you have a bit of a learning curve coming up! Have you got a design for these windows? - thats the starting point.
This the last one I did:

.View attachment 117979

In the workshop - the half round part of the frame is in two pieces. Cut out with a band saw then the inner face and rebate cut with a spindle moulder and ring fence with the workpiece attached to an exact mdf pattern of the shape.
Outer edge just cleaned up roughly as it would be out of sight.

View attachment 117980
Looks good Jacob....what timber did you use...esp for inner curve?
 

Jacob

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Looks good Jacob....what timber did you use...esp for inner curve?
Redwood throughout, except for the inner curved glazing bars which were recycled from the original frames. They were steam bent oak and still in perfect condition.
The rest was in poor condition mainly at the cills and bottom ends of stiles so total new-build was easier.
10 altogether - exact replicas of the originals and reused the glass.
 

Phill05

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Hello,
I wonder if anyone have experience in CNC machines, and how to use them to cut custom size sash frames from half circle made profiles?
Greg, a starting point would be the size of window you require, rough drawn by pencil on paper is fine so long as you know they are correct, I have been making replacement sash window for years the old school way, after an accident stopped me I only work at a desk now so went into designing for cnc machine, once you have the design sizes it can be very easy to cut out.
 

deema

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If you don’t know how to use CAD, it’s a fairly steep learning curve if you have no experience of it at all. Once you have the design in CAD you then take the file and convert it into tooling paths that the robot or CNC machine will follow. A lot of this can be automated, but still needs a user who is aware of what is happening to avoid expensive crashes that ruin your day. If I were going down this route, I would have a robot arm possibly mounted on a track to provide maximum flexibility. Robots are fairly cheap….well they were six years ago when I last bought a big welding robot!

Jacobs method is the tried and tested system for many years. To make a template requires no dexterity. You simply make a tramel for your router. That’s a fancy way of saying bolt your router to a length of plywood or similar, stick a screw through the ply a distance away from the cutter equal to the radius you want and using the screw as the point of a compass cut a perfect circle , arch or whatever. For ovals or other shapes, there are methods of creating jigs to create the shape, google is your friend.

Once you have the template cut out, you attach it to the stuff that’s been roughed to approximately the right shape. You need to read up / get training on how to use jigs on a spindle moulder. Anyway, there are two main methods, the first is a ring fence that Jacob mentioned. These usual provide a lead in and a lead out for the work, and as such require a little technique to ensure you cut the stuff over a certain spot on the ring. The other is to use a bearing follower, you have to create your own lead in and lead out, usually by extending the template. These require no technique as the cut will be perfect regardless on where the stuff is placed in the bearing. The reason the Bearing Method is not necessarily used as the main method is that the bearing has a fixed diameter and you have to match the bearing to the cutter. A ring fence can vary the depth of cut and therefore be matched exactly to the cutters. So, typically you will find a ring fence being used.
 

Jacob

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yes. There's lots of variations on how to do it. If you were doing rebate or moulding, the ring could go against the workpiece itself and so on
Ring fence is a bit intimidating at first but once you've got it it can be surprisingly easy
Just re-visited this.
A template not needed for the curved frame and with hindsight it's not what I did. Had a memory blip!
The 2 pieces for the head were marked up with the aid of of a pivoting rod - a lath pinned at one end with drill holes for the pencil lines at the other - the pivot on a block in the middle same thickness as the frame pieces.
Then band sawn close to the line.
Then taken back to the line with a drum sander on the inside face - a primitive fixed device in a drill chuck on a drill stand i.e. taking the workpiece to the machine.
This sort of thing Amazon.co.uk
And/or bits of the curved offcuts used as a hand sanding block - exactly the right radius!
The outside face with a flat sander or left band sawn - accuracy not essential.
Then placed on the rod (full size detail drawing on a bit of ply) to pick up the marks for the mortices.
Then morticed and other details (the "bridle" joints at the top and to the stiles)
Then the rebate machined on the spindle with a ring fence - no template required, the rebate just follows the finished face.

Got a few snaps somewhere I'll see if I can find them. Often difficult to record stuff with interesting photos and to do the work at the same time! The recording takes longer than the work, unless you've got a handy film crew standing by.

PS but yes a template is another route.
 
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