easiest way to cut 5" disc out of mdf

[camele]

hi every one i was hoping on a couple of hints on cutting some 5" disc out of mdf i need a hole in the middle as well about 1" all hints would be greatly recived
thanks craig

[Bushmiller]

Craig

A lot depends on how many discs you need to make and if you have a router. It may be easiest to make up a template and use a flush trimming bit with a top bearing. This is very easy if you are able to fix the template to your mdf with a couple of small screws.

Regards
Paul

[camele]

thanks paul i have a lot to cut proably about 40 out of 12mm mdf i will make a template and start cutting
thanks craig

[Bushmiller]

[QUOTE=camele;1581823]thanks paul i have a lot to cut proably about 40 out of 12mm mdf i will make a template and start cutting
thanks craig[/QUOTE

Craig

Template is the way to go for that quantity. You can put a pilot hole in the centre of the template too and drill that at the same time you use the router. Then the hole in your disc can be enlarged with the correct sized spade or forstner bit.

Also the exact way you go about this depends on the level of accuracy you require for the project.

Regards
Paul

[crowie]

You could also use bi-metal holesaws or T/C holesaws for 40 of them???

[Bushmiller]

You could also use bi-metal holesaws or T/C holesaws for 40 of them???

Crowie

Good idea, which I hadn't thought of. 125mm is pretty big so I think you would need a drill capable of quite a slow speed.

Regards
Paul

[camele]

unfortanatly i dont have a drill press but if i did that would b the go. i think the best way will b the router
thank for the tips guys craig

[colbra]

hi every one i was hoping on a couple of hints on cutting some 5" disc out of mdf i need a hole in the middle as well about 1" all hints would be greatly recived
thanks craig

Hi Camele
I would like to offer some help to you on the cutting of 5” disc I am not sure what tools you have available to you but here is a method of cutting a disks with a band a saw if you do not have a band saw go to your nearest men’s shed they would have one and may even do the job for you here is a video of the procedure Cutting discs on a bandsaw, using a simple jig - YouTube (http://www.youtube.com/watch?v=GDKLyAe8zt0)
There are other jigs that you could use you can see them all on You Tube.
If you need more help or information just PM and I will assist you. there are other simple jigs you could make as well.

Colbra:)

[A Duke]

You could use a trammel on your router and the pivot hole in the centre would be the centre for a forstner bit or spade bit.
The guide plate that comes as standard with a Triton router would be ideal.
Regards

[Bushmiller]

You could use a trammel on your router and the pivot hole in the centre would be the centre for a fosner bit or spade bit.
The guide plate that comes as standard with a Triton router would be ideal.
Regards

Hugh

I have found that is the easiest option for larger circles, but I didn't mention it in this case because because the radius of the hole will be relatively small and a bit fiddly to set up unless the router is small. A laminate trimmer might suit but their fence system does not usually have provision to insert a single rod.

Regards
Paul

[A Duke]

Hugh

I have found that is the easiest option for larger circles, but I didn't mention it in this case because because the radius of the hole will be relatively small and a bit fiddly to set up unless the router is small. A laminate trimmer might suit but their fence system does not usually have provision to insert a single rod.

Regards
Paul
Paul,
You are probably right, two and a half inches radius is rather small.
Trying to solve some one else's problems is difficult as you have less than half the info, only what they want to do and not the available equipment and skill level.
It could be as simple as telling a computer to tell the CNC what to do.:wink:
Regards

[nrb]

I have never had much luck useing a hole saw,the disc get stuck in the saw,IMO the router path is the neatest way to go

[joe greiner]

Five inch is probably too small for this: http://www.woodworkforums.com/f88/router-compass-50372/

but you could use an auxiliary base plate with a pivot at 2.5" radius (a simple nail projecting downward). The nail hole in the stock can provide a target for the Forstner bit.

Cheers,
Joe

[cadas]

What you need to achieve is a,say 150mm dia template to use with a guide bush, that will do the 5" dia piece.

But before you cut that, if you have a drop in piece with a smaller hole (like a donut shape) you can do the inner hole first, remove the piece and do the outer.

Hole saws and router + trammel will let you make the pieces.

Care needs to be taken routing the big piece as it becomes detached, so either don't rout full depth, stick the piece down before routing, or have a drop in plug that goes in the small hole and fixes the piece in the jig.

[camele]

thanks for the segestions i will also contact the local men's shed in the area as i would like to do this with limiting the dust. i am at present saving for a dusty and a couple of other things but at the moment funds all go to the house and projects for the kids. i don't have a lot of experience working with wood. but i like to learn that what it is all about. again thanks for the help Craig

[akuntz]

I built a drum sander awhile back and it was built out of 5" circle of MDF and they showed the band saw jig and it worked perfect
Al

[steamingbill]

Here is how I do it to ensure concentric circles with minimum bother

1. Rough cut the discs on the bandsaw or table saw or whatever you've got

2. Drill the 1" centre hole for the axle

3. Make a circle cutting jig for either the bandsaw or the router table or a template for a hand held router - whichever way you go use a 1" dowel as the pin

4. Use the jig to make the final circle

5. The 1" centre hole in all discs is guaranteed to be exactly in the centre of the final disc

6. If you havent got tablesaw bandsaw or router (and it sounds like a drum sander build) you might get away with gluing the rough cut discs to the axle and then using a big sandpaper plate to grind them all into a cylinder without going through the hassle of cutting all the individual discs - But big dust hazard this way - need to do it outside and with very good breathing protection.

Bill

[Age_jay]

You could try this: An easy way to cut a circle in 3mm MDF - YouTube (http://m.youtube.com/watch?v=XWH3ysrfrjM)

[Bushmiller]

Thanks for posting that method Age_jay and welcome to the forums.

Regards
Paul