Disc sanders

[marcros]

What do I need to consider in a disc sander?

I would like to use it for general tasks, and for mitres on 4-5" box sides. I presume that this will require a minimum of 12" discs, good solid table and a decent fence?

 

[Glynne]

I've been really pleased with my SIP disc sander.
For tuning mitres, you might want to make a vertical fence so as to reduce the speed variance across the workpiece i.e. if the piece is presented horizontally, one end will be near the centre of the disc whilst the other will be to the outside edge.

 

[RogerP]

Most of the major retailers sell their own badged version of the far eastern 12" disk sander.

But they are not all equal. Some have aluminium tables and other far better cast iron ones. They also have different quality mitre gauges, some plastic and some much better metal ones.

I think the Record DS300 from Screwfix for a penny less than 200 quid is the best buy.

 

[marcros]

I've been really pleased with my SIP disc sander.
For tuning mitres, you might want to make a vertical fence so as to reduce the speed variance across the workpiece i.e. if the piece is presented horizontally, one end will be near the centre of the disc whilst the other will be to the outside edge.

I hadn't thought of that, but surely whether it is vertical or horizontal, it is at the same point on the disc?

 

[Tetsuaiga]

I didn't think about the speed difference when I bought mine.

If you are using a fence though I can't imagine it will effect the final shape. For freehand work you have to be aware of it though.

I bought the record one and its working fine.

 

[Glynne]

I picked that up from Andrew Crawford. There will always be a speed differential but provided the height of your mitre is less than the radius of the disc, you can move a vertical fence slightly to the side and so minimise the difference. I just find it a little easier that the sanding is more consistent over the length. I'll post a picture of mine later when the Grandkids go home!

 

[woodbrains]

Hello,

If you are likely to change grits regularly, perhaps the hook and loop discs would be better. The PSA backed discs are generally stuck 'till they are worn out as removing them destroys them. It will get expensive if the discs tear every time you want to change to a different grit.


Mike.

 

[Kalimna]

I have a Jet belt n disc dander, and started with the Velcro discs. I found that there was a fair amount of rounding over due to the softness / springiness of the hook and loop material. I can't imagine that is a good thing for accurate mitreing.
I switched to the glued-on discs.

Adam S

 

[deema]

I bought a secondhand lathe initially as a cheap solution for a disc sander. It tuned out rather well pardon the pun, as I now enjoy turning, something I hadn't done before. Equally a nice old lathe will keep its value.

 

[MMUK]

I've a disc sander made from an old washing machine motor. Only runs at about 500rpm so direct drive and very torquey. Cost next to nothing to make as the framework was built from various offcuts.

 

[No skills]

I bought a secondhand lathe initially as a cheap solution for a disc sander. It tuned out rather well pardon the pun, as I now enjoy turning, something I hadn't done before. Equally a nice old lathe will keep its value.

I've been thinking about doing just that for quite a while, any particular problems with this?

 

[RogerS]

I'm going to buck the trend and say 'Why bother'? Like you, I thought that a disc sander would be a really handy piece of kit. I've tried two - at different price points. All had one problem or more. Most often was poor runout on the actual sanding disc. In other words as it spun the distance between its surface and that of the workpiece varied. So this means that you can adjust your table to be square to the disk at one point but then spin the disc and it is no longer square. This runout was not an exception as I got replacements to both machines and both replacements were just as bad.

Changing grit is a PITA if you are using the adhesive discs and don't even think that you can put the one back on again to change back.

Also be careful of burning of the ends especially with hardwood.

I got rid of both. I use my Axminster mitre trimmer. Much better, IMO

 

[marcros]

i would go with a trimmer, but as far as I am aware, they cannot cut a mitre on the end of a box side 100mm wide. A shooting board and plane is an alternative.

I would also like to use it for trimming the end of pen blanks.

That said, something with no run-out on the disk will be essential. I am not expecting to need to have to change grits often- only when the disc is worn out.

 

[RogerS]

You could always keep your eye open for a Morso or something like this http://www.ebay.co.uk/itm/MARIGOLD-MITR ... 1710595205

 

[marcros]

i had one but it wouldn't take the pieces that tall, and it seemed to grab and pull the cut. Part of it would be glass smooth, the other part not so.

 

[No skills]

As you have already mentioned a shooting board seems the best solution to your box problem, also gives some justification to the purchase of a suitable plane of good pedigree.

I would imagine a lathe based sanding disk could be tweeked for good performance if you were willing to put in work making a suitable table/guide for it, plus you could have more than one disk so swapping to different grits wouldn't destroy the sanding sheets.

 

[Peter Sefton]

I have one of these and I am not impressed.

http://www.axminster.co.uk/axminster-ho ... isc-sander

One of my students has one of these and it looks much better.

http://www.axminster.co.uk/axminster-tr ... isc-sander

But it is more than double the money, I wish I had saved and waited

Cheers Peter

 

[marcros]

I knew the two models that you were referring to when I saw that they were axminster, before clicking on the links.

For now, I think I will save and hold fire.

 

[Glynne]

Sorry, I forgot I said I would post some pictures of my mitre sanding jig.

Pretty straightforward really, just 18mm MDF on a hardwood runner which runs in the mitre gauge slot.
I tend to use it as far left as possible as this gives the minimum speed differential. The fence is ~ 110mm high and I used a 2nd piece of MDF as the first wasn't quite at 45 degrees.
The sandpaper on the SIP glues straight onto the metal plate so there isn't any "give" as you might have with a velcro fastening. Changing the paper is a bit of a faff but the tip to getting the old adhesive off is to use acetone - cheap nail varnish remover from Superdrug or any discount chemist (tip courtesy of Peter Sefton).
Despite being pretty accurate in build, you do need to finesse where you sand so you can't just bung it on and expect good results.
I also use a Donkey's Ear shooting board for final tweeking.

 

[woodbrains]

Hello,

Do you have a router table? A 45 degree chamfer bit and a sled to which the work is clamped, running in a mitre slot, is efficient for batch production. Use different chamfer bit angles and boxes of many sides can easily be made. There is no sensible maximum height a mitre can be made and outlay is minimal.

Mike.