How to thickness thin workpieces?

[Charlie Woody]

I have some thin pieces of oak that vary in thicknesses along each piece, 2 - 6 mm.

To rectify this I am considering two methods for the planer / thicknesser:

1. Make an "extra" bed of 18 mm mdf with a batten underneath each end to fit over the thicknessing table; pass the workpiece over this.
2. Use double sided tape to attach the workpiece to 18 mm mdf and pass through the thicknesser.

I don't have a belt sander or drum sander which are the only other ways I can think of doing this.

Which way would you do this please?

 

[carlb40]

I would try to track down a local commercial shop with a drum sander. Even taped down securely i doubt anything much below 6mm would survive a thicknesser.

Sanding would be the safest way IMO

 

[jasonB]

I just put a bit of melamine faced board on the table with a batten to stop it moving and have no problem thicknessing down to 2mm. It does depend on the grain of the wood a bit, if its short you can get the board breaking up don't try to take too big a cut either. This little box is 3mm thick

J

 

[RogerP]

I've used both methods but now stick to the first - making sure there's no metal used in the construction that can possibly touch the planer knives. I made the add-on bed from 24mm birch ply and made it extra long so I've effectively a metre long thicknesser bed which also is a great help eliminating snipe. I waxed the ply to a high shine.

 

[marcros]

i would look at building a drum sander if it is more than a one off. I found some plans http://woodgears.ca/sander/thickness.html that dont look too complex.

That said, jason's results show that his method works, so maybe no need to do any mmore than he suggests.

 

[AndyT]

You don't say what width and length these pieces are.
The simplest way might well be to nail one end down and use a hand plane.

Or if they are narrow strips there are several designs favoured by guitar makers in which a plane blade is held on an adjustable block and the strip is pulled through so the blade is scraped down to the thickness required. Jimi43 had a good design IIRC.

 

[SurreyHills]

I use the first method. You need to be careful when you do thin strips, <4mm, as they can split under the pressure of the infeed/outfeed rollers and the cutter block.

 

[custard]

Hello Charlie, JasonB put his finger on it, it's all about the grain of the timber that you're trying to thickness. Look at the edge of the wood and if you see the grain running smoothly along the length then you're golden. If on the other hand the grain runs in and out of the workpiece every few inches then it doesn't matter what kind of sled you build, the workpiece is still pretty likely to self destruct.

I used to thickness laminations on a thicknesser down to 1.5mm and with really straight grained wood (and sharp knives) it wasn't a problem, but for wilder grain there's just no substitute for a drum sander. Although there's an argument that for any wood thinner than about 4 or 5mm it's not best practise using it if there's short grain, so some people say that a drum sander encourages sloppy technique in that it allows you to use structurally inferior timber.

 

[Peter Sefton]

Hello Charlie, JasonB put his finger on it, it's all about the grain of the timber that you're trying to thickness. Look at the edge of the wood and if you see the grain running smoothly along the length then you're golden. If on the other hand the grain runs in and out of the workpiece every few inches then it doesn't matter what kind of sled you build, the workpiece is still pretty likely to self destruct.

I used to thickness laminations on a thicknesser down to 1.5mm and with really straight grained wood (and sharp knives) it wasn't a problem, but for wilder grain there's just no substitute for a drum sander. Although there's an argument that for any wood thinner than about 4 or 5mm it's not best practise using it if there's short grain, so some people say that a drum sander encourages sloppy technique in that it allows you to use structurally inferior timber.

I agree with both Jason and Custard, we regularly thickness down to 2mm, just put a waxed spare piece of melamine faced MDF with a baton fixed to the underside to act as a stop against the thicknesser bed. Let the feed rollers pull the lathes through the thicknesser in .5mm passes, I would also leave the thin bits at least 100mm over length to allow for any snipe, but it is all about straight grain.
Cheers peter

 

[Eric The Viking]

I agree with both Jason and Custard, we regularly thickness down to 2mm, just put a waxed spare piece of melamine faced MDF with a baton fixed to the underside to act as a stop against the thicknesser bed. Let the feed rollers pull the lathes through the thicknesser in .5mm passes, I would also leave the thin bits at least 100mm over length to allow for any snipe, but it is all about straight grain.
Cheers peter

Yebbut haven't you got that gorgeous Hammer jobbie with the helical cutter head?

IIRC it's got rubber rollers, or at least feed rollers with very light pressure, and the helical thing anyway means very little force on the stock. Wonderful finish, if I remember, too.

It's a bit like saying your Murcielago has no trouble outrunning the Police! The rest of us have Ford Fiestas (in comparison).



E.

 

[Peter Sefton]

I agree with both Jason and Custard, we regularly thickness down to 2mm, just put a waxed spare piece of melamine faced MDF with a baton fixed to the underside to act as a stop against the thicknesser bed. Let the feed rollers pull the lathes through the thicknesser in .5mm passes, I would also leave the thin bits at least 100mm over length to allow for any snipe, but it is all about straight grain.
Cheers peter

Yebbut haven't you got that gorgeous Hammer jobbie with the helical cutter head?

IIRC it's got rubber rollers, or at least feed rollers with very light pressure, and the helical thing anyway means very little force on the stock. Wonderful finish, if I remember, too.

It's a bit like saying your Murcielago has no trouble outrunning the Police! The rest of us have Ford Fiestas (in comparison).



E.

I have demonstrated the new Hammer with the helical block but don't have one myself My A341 is about 9 years old and has the standard 3 knife block and metal feed rollers, these will leave printing marks on the thicknesses timber if I cut less than .4mm.
I haven't used a planer with rubber rollers since the 1980s when I had a Startrite. I am not sure what planer Charlie has but this is how I use mine, I wouldn't try to produce anything of an equal thickness over the top of a surface planer if I have a thicknesser to hand.
Cheers Peter

 

[custard]

I agree with both Jason and Custard, we regularly thickness down to 2mm, just put a waxed spare piece of melamine faced MDF with a baton fixed to the underside to act as a stop against the thicknesser bed. Let the feed rollers pull the lathes through the thicknesser in .5mm passes, I would also leave the thin bits at least 100mm over length to allow for any snipe, but it is all about straight grain.
Cheers peter

Yebbut haven't you got that gorgeous Hammer jobbie with the helical cutter head?

IIRC it's got rubber rollers, or at least feed rollers with very light pressure, and the helical thing anyway means very little force on the stock. Wonderful finish, if I remember, too.

It's a bit like saying your Murcielago has no trouble outrunning the Police! The rest of us have Ford Fiestas (in comparison).



E.

Eric, I use a Felder with rubber rollers, but all rubber rollers mean is a smaller minimum cut on each pass. If I try and thickness wild grain boards below 3mm they still regularly get chewed up as even the tiniest bit of tear out quickly translates into a fluttering workpiece which then self destructs if it's too thin.

However, I used to successfully thickness 1.5mm laminations on a De Walt portable thicknesser with a sled, but pulling that trick off meant scouring the timber yards for dead straight grained stock.

So, my experience encompasses a £20k machine that can't reliably thickness wild grained thin stock, and a £200 machine that could reliably thickness straight grained thin stock. That's why I say thicknessing thin boards is more about the wood than the thicknesser.

Nowadays I have access to a drum sander, and for laminations that's what I'll use. But there's a nagging doubt that I'm compromising build quality by using too much short grained wood, where as putting it all through a thicknesser forces you to seek out straight grained material which guarantees your laminated components are that much stronger.

 

[Peter Sefton]

I agree with Custard.
Cheers Peter

 

[Eric The Viking]

Yebbut haven't you got that gorgeous Hammer jobbie with the helical cutter head?

I have demonstrated the new Hammer with the helical block but don't have one myself

Aha!

Sorry Peter, I didn't mean to traduce your good name!

I was there; I watched your excellent demonstration; I was suitably awestruck... I thought you'd just bought it!

Seriously, the helical block lends itself to thin gnarly stock. Because there's such a small area of knife contact, and it's a shearing cut, the backwards force on the stock is greatly reduced. If it doesn't have rubber rollers, at least the roller pressure can be a lot less than with a traditional cutter block. It would be a win-win thingy.

My guess about an ideal machine would be one where you can swap the rollers easily - splined for heavy and rough stock, and rubber for finer work.

I did like the Hammer, but sadly, not in this lifetime.

E.

 

[PAC1]

Unless there is miles of the stuff why not saw it 0.5mm oversize and then hand plane it to size.

 

[Mr T]

Like Peter I have a Hammer (sound like a song) an A3-31 with the bog standard block.
Yesterday a student was doing some saw cut veneers in quarter sawn oak. They went through the planer down to 3mm just fine. We fed them through on a piece of 18mm ply, we didn't bother sticking it down, just held it firm until it was under both rollers. It came out looking like this. I agree with others that straight grain is very important,

 

[Peter Sefton]

Yebbut haven't you got that gorgeous Hammer jobbie with the helical cutter head?

I have demonstrated the new Hammer with the helical block but don't have one myself

Aha!

Sorry Peter, I didn't mean to traduce your good name!

I was there; I watched your excellent demonstration; I was suitably awestruck... I thought you'd just bought it!

Seriously, the helical block lends itself to thin gnarly stock. Because there's such a small area of knife contact, and it's a shearing cut, the backwards force on the stock is greatly reduced. If it doesn't have rubber rollers, at least the roller pressure can be a lot less than with a traditional cutter block. It would be a win-win thingy.

My guess about an ideal machine would be one where you can swap the rollers easily - splined for heavy and rough stock, and rubber for finer work.

I did like the Hammer, but sadly, not in this lifetime.

E.

No problem I am still saving up, I have used it a couple of times and I am due to demonstrate at Milton Keynes at there Open day 5th April, not sure what they are going to let me loose on :!: but it should be fun.
Cheers Peter

 

[Peter Sefton]

Unless there is miles of the stuff why not saw it 0.5mm oversize and then hand plane it to size.

Absolutely, I find it's best to screw fix or cramp the timber and plane it in tension so you are dragging it flat. I remember when I was a student at college I had a fellow teenager along side me who was an apprentice with John Makepeace he hand planed a stack of Sycamore laminations before creating a classic Makepeace inspired organic tree table, a very talented young man.
Oh to be a teenager again Peter

 

[n0legs]

Unless there is miles of the stuff why not saw it 0.5mm oversize and then hand plane it to size.

Absolutely, I find it's best to screw fix or cramp the timber and plane it in tension so you are dragging it flat. I remember when I was a student at college I had a fellow teenager along side me who was an apprentice with John Makepeace he hand planed a stack of Sycamore laminations before creating a classic Makepeace inspired organic tree table, a very talented young man.
Oh to be a teenager again Peter

Peter being a learner, and maybe a bit dull #-o . Could you explain what you mean by "plane it in tension".
I watched Gramps plane many a yard of timber when I was a kid, but cant work out what you mean. I don't want to give the impression I can't use hand tools, Gramps made sure I could, but I can't work that out.
Thanks n0legs.

 

[Racers]

Clamp one end down and plane away from the clamp, then turn it round and do the same for the other end.
Like pulling a Japanese saw the tension keeps the blade (or in this case stock) from buckling.

I have done short thin pieces with a No8 as the front of the plane completely covered the stock keeping it flat.

Pete