Creating Angled Joints on MDF - Box Building

[Bungle]

Hi

I've been trying to find somewhere where I can get advice on this issue, maybe this might be the right place

Basically I'm building a speaker bass enclosure, it's a slanted front type which means the joints on the slant side have to have an angled edge to join & screw them together (if you get what I mean). I can't seem to find a tool that will create these angles for me. I'm using 21mm MDF. All the circular saws I look at do up to 45degrees as well as jigsaws, mitre saws, routers etc. The angles I need are more like 70-80 degrees (got the exact figures somewhere - will need to dig them out). Bearing in mind I'm on a budget and looking for a cost effective solution that I could use a few times in the future but not every day.

Any help appreciated

Thanks

 

[Racers]

Hi,

Hand plane? or can you cut half the angle on each edge?


Pete

 

[Bungle]

Suppose I could cut the 45 with a saw then plane the rest as close as possible, I remember using a plane in the past many years ago to try and do this but it turned out a right mess ! couldn't get a decent straight edge

 

[CNC Paul]

Bungle,

If I understand you correctly, you want to bevel the sides 70/80 degrees, a saw will go from 90 to 45 degrees so if you lay the sides flat on the table you can cut any angle between 90 and 45 degrees.

 

[Steve Maskery]

Bungle - Hi

I don't understand quite what you mean. Do you really want to cut an 80 deg bevel? That would give you an acute edge sharper than a chisel - is that what you mean? If so, then I think ripping on edge on the TS is the best solution, but you will have guarding problems, I think, and If you have trouble using a plane then I think it's unlikely that you should be attempting an advanced technique like this. I don't mean to be rude, not at all, but it just seems a bad idea to me.

However, if you mean you want the resulting edge angle to be 80 deg, then that means a 10 deg bevel, which is a much more achievable result. Bevel it on the tablesaw (your guard should not be a problem) then clean up with a sharp block plane. You should need just a pass or two.

Cheers
Steve

 

[neilyweely]

Bungle

I know exactly what you mean, I have made speaker enclosures to fit behind car seats, and required these type angles.

Tablesaw is the way I do it, but in the beginning I used to cut the top and bottom of the box to the right lengths and then use a timber insert to fill where the gap was left. In other words the front of the speaker rested against the edges of the top and bottom, and gaps were then filled.

As the top and bottom of the box are different widths the front would sit on the top edge of the bottom and the bottom of the top piece. The strip was then inserted and glued in, resulting in a solid top and bottom, and a good looking joint. I don't think you would have any problem doing this as long as your edges are straight so your front fits airtight.

If you cut the front oversize, so it laps over the edges of the top and bottom, then you can plane it down to fit quite easily, by using the top and bottom as a flat edge/reference and planing down level with them. Sorry, i am not so good at explaining myself.

I make enclosures for the local music shop once in a blue moon, and now I use the table saw as Steve says. However the method I described above works well. I used to varnish a strip of wood and use it to fill the gap but disguised as a feature!! It worked well.

I hope this helps

Neil

 

[Bungle]

Bungle

I know exactly what you mean, I have made speaker enclosures to fit behind car seats, and required these type angles.

Tablesaw is the way I do it, but in the beginning I used to cut the top and bottom of the box to the right lengths and then use a timber insert to fill where the gap was left. In other words the front of the speaker rested against the edges of the top and bottom, and gaps were then filled.

As the top and bottom of the box are different widths the front would sit on the top edge of the bottom and the bottom of the top piece. The strip was then inserted and glued in, resulting in a solid top and bottom, and a good looking joint. I don't think you would have any problem doing this as long as your edges are straight so your front fits airtight.

If you cut the front oversize, so it laps over the edges of the top and bottom, then you can plane it down to fit quite easily, by using the top and bottom as a flat edge/reference and planing down level with them. Sorry, i am not so good at explaining myself.

I make enclosures for the local music shop once in a blue moon, and now I use the table saw as Steve says. However the method I described above works well. I used to varnish a strip of wood and use it to fill the gap but disguised as a feature!! It worked well.

I hope this helps

Neil

Ahhhhh neilyweely my hero ! I was wondering it may be difficult to explain to anyone who's not tried to build a box to fit behind a car seat ! talk about right time right place. Thanks for the tips, I'll chew it over right now !

 

[Bungle]

Bungle - Hi

I don't understand quite what you mean. Do you really want to cut an 80 deg bevel? That would give you an acute edge sharper than a chisel - is that what you mean? If so, then I think ripping on edge on the TS is the best solution, but you will have guarding problems, I think, and If you have trouble using a plane then I think it's unlikely that you should be attempting an advanced technique like this. I don't mean to be rude, not at all, but it just seems a bad idea to me.

However, if you mean you want the resulting edge angle to be 80 deg, then that means a 10 deg bevel, which is a much more achievable result. Bevel it on the tablesaw (your guard should not be a problem) then clean up with a sharp block plane. You should need just a pass or two.

Cheers
Steve

Hi Steve

OK I have a pic if the profile of the box showing the angles, if I can get them close to this then I can work with the rest. I know what you're saying by trouble using a plane and all that but this is a DIY project and I can't stretch to a table saw anyway, so I'll stay away from those as a beginner, anyway doesn't practice make perfect (or somewhere close), everything I've done in life has been by practice which also includes stripping down engines and re-building, and even those I made a few errors over the years, but now with experience I am confident at that ! so I'm happy to cock-up on my own builds if only to become more proficient down the line.

Bugger, I'm not sure how to upload the pic to the post ! yikes

 

[Bungle]

OK, since I can't upload the pic, it's 60.8 degrees call it 60 degree edge/bevel/chamfer whatever you like to call it

 

[MickCheese]

Am I the only one confused! :?:

My circular saw will cut a 60 degree bevel down the edge of a board, it's somewhere between 90 and 45 degrees.

Am I going to wish I didn't ask?

Mick

 

[yo_chuci]

every sub box i made in the car world was done with a circular saw...
most saws can go from vertical to 45degs...
you need 60degs... so turn the board over and cut from the other end at 30degs... ( i think if my brain is working correct...)
i could always work it out when looking at the mdf anyway lol... you just have to reverse everything i think... ie cut from the inside of the box not out and the bit you want is on the wrong side of the saw (eg if the bit you normally keep is under the wide part of the saw base when you flip and reverse you want AND MEASURE FOR the other bit) hope that helps and makes sense...

you don't need a speaker for the hole do you?

 

[Bungle]

Am I the only one confused! :?:

My circular saw will cut a 60 degree bevel down the edge of a board, it's somewhere between 90 and 45 degrees.

Am I going to wish I didn't ask?

Mick

Oh bugger, have I been thinking about this all wrong ! You may have a point there Mick, I am a total beginner at woodworking ! flat packs I can do tho

 

[Bungle]

every sub box i made in the car world was done with a circular saw...
most saws can go from vertical to 45degs...
you need 60degs... so turn the board over and cut from the other end at 30degs... ( i think if my brain is working correct...)
i could always work it out when looking at the mdf anyway lol... you just have to reverse everything i think... ie cut from the inside of the box not out and the bit you want is on the wrong side of the saw (eg if the bit you normally keep is under the wide part of the saw base when you flip and reverse you want AND MEASURE FOR the other bit) hope that helps and makes sense...

you don't need a speaker for the hole do you?

mmmm yess, I just realised what Mick was saying. Bugger. I'll go bury my head in a pond with crocs now....

no speakers required thanks, i'm gonna sit inside the box banging my head agains it !

 

[MickCheese]

Set the angle, don't have too much blade sticking out under the cut and don't cut through your floor or the saw cable. Take it slow and run against a batton to keep the cut straight.

Score the line with a stanly knife before cutting and it should prevent too much breakout if you are using ply.

Good luck, let us know how you get on.

Mick

 

[miles_hot]

If you lack the tools for the job there are a number of options
1) ask around on here, I've found people on here incredibly generous with their time as well as knowledge and someone may be able to help you out in return for some nice gesture.
2) leap with happy abandon down "the slope" and buy tools...

 

[hog&bodge]

If you lack the tools for the job there are a number of options
1) ask around on here, I've found people on here incredibly generous with their time as well as knowledge and someone may be able to help you out in return for some nice gesture.
2) leap with happy abandon down "the slope" and buy tools...

Think this would have helped with a sketch...
Take a pic when finished.... :wink: 2)
leap with happy abandon down "the slope" and buy tools...
Is the option I would go for \/

 

[Bungle]

Set the angle, don't have too much blade sticking out under the cut and don't cut through your floor or the saw cable. Take it slow and run against a batton to keep the cut straight.

Score the line with a stanly knife before cutting and it should prevent too much breakout if you are using ply.

Good luck, let us know how you get on.

Mick

Thanks Mick, sorry for the arse about face confusion ! I'm happy to buy a half decent circ saw for the job, I think this will come in handy for future anyway. I'm cutting MDF and was thinking of a fine cut blade of sorts.

 

[Anonymous]

Hi

I've been trying to find somewhere where I can get advice on this issue, maybe this might be the right place

Basically I'm building a speaker bass enclosure, it's a slanted front type which means the joints on the slant side have to have an angled edge to join & screw them together (if you get what I mean). I can't seem to find a tool that will create these angles for me. I'm using 21mm MDF. All the circular saws I look at do up to 45degrees as well as jigsaws, mitre saws, routers etc. The angles I need are more like 70-80 degrees (got the exact figures somewhere - will need to dig them out). Bearing in mind I'm on a budget and looking for a cost effective solution that I could use a few times in the future but not every day.

Any help appreciated

Thanks

Many high-end hi fi speaker manufacturers use a mitreloc cutter to do this. I bought this one and it works very well
http://www.axminster.co.uk/product.asp?pf_id=22970&name=mitre&user_search=1&sfile=1&jump=44

 

[MickCheese]

Hi

I've been trying to find somewhere where I can get advice on this issue, maybe this might be the right place

Basically I'm building a speaker bass enclosure, it's a slanted front type which means the joints on the slant side have to have an angled edge to join & screw them together (if you get what I mean). I can't seem to find a tool that will create these angles for me. I'm using 21mm MDF. All the circular saws I look at do up to 45degrees as well as jigsaws, mitre saws, routers etc. The angles I need are more like 70-80 degrees (got the exact figures somewhere - will need to dig them out). Bearing in mind I'm on a budget and looking for a cost effective solution that I could use a few times in the future but not every day.

Any help appreciated

Thanks

Many high-end hi fi speaker manufacturers use a mitreloc cutter to do this. I bought this one and it works very well
http://www.axminster.co.uk/product.asp?pf_id=22970&name=mitre&user_search=1&sfile=1&jump=44

That's a good idea. If your boards are straight it should produce a really tight clean joint. I bet it creates a lot of dust!

Mick

 

[FatFreddysCat]

In shop fitting we often have to cut acute angles and joint MDF. Two tips - for acute angles make-up a sled which holds the work at 45 degees on the table saw as this will allow really extreme angles to be cut. A similar device can be useful to have for your chop saw. Second tip - when assembling mitre joints lay the two pieces to be jointed flat on the bench and tight together with some wide self-adhesive tape beneath the joint. Spread glue on the joint and "fold" the two pieces together. The tape will assist in getting a clean joint providing care is taken in cutting the original joint. These processes work for me as many counters and bars over the years have proved