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Tiger
12th Jul 2010, 11:22 AM
Following the turn-on at 's on the weekend, I went back to a Kauri pine plate that I had worked on some time ago but was unhappy about the final product.
I sought Ken W's advice with shear scraping and tried various forms of shear scraping on this plate. After much effort and constant grinding/honing of scrapers and gouges there was still some tearout. I then tried the sandpaper route and starting at 120 grit, I went through to around 1000 grit but it took a good 30 mins or so (and I was just doing the inside) to get an acceptable result. I should say that I was trying to remove all scratches and indications of tool marks.

I'm wondering how much sanding do you need? Is it normal to spend more time sanding rather than using the tool in faceplate work with some of the softer woods? Sanding obviously has its place as nothing else I had tried could get rid of the final tear out but it seems an excessive time requirement.

RETIRED
12th Jul 2010, 11:55 AM
Is it normal to spend more time sanding rather than using the tool in faceplate work with some of the softer woods?

Short answer on Kauri, yes. Some Meranti's, the same.

Tiger
12th Jul 2010, 12:03 PM
Thanks, because I was starting to question my sanding technique. Probably should get a list of timbers that I should avoid when doing faceplate work, if you care to mention any others I will make a note of them.

Anyway, I thought you were still cleaning up after the weekend:U.

Manuka Jock
12th Jul 2010, 12:21 PM
Yep , Kauri is a sandpaper manufacturers friend :D
Take your time , reverse sand every second size grit if possible , and when you think that you have done each grit enough , do a wee bit more.
Damp wipe between sandings too if need be .

Tiger
12th Jul 2010, 12:24 PM
Jock, unfortunately the MC900 lathes don't have a reverse switch :(. Might be worth investigating to see what modification would be necessary to have reverse, more things to do:;.

Rhys_holland
12th Jul 2010, 12:50 PM
Jock, unfortunately the MC900 lathes don't have a reverse switch :(. Might be worth investigating to see what modification would be necessary to have reverse, more things to do:;.
if your power sanding just put the drill in reverse

Manuka Jock
12th Jul 2010, 12:55 PM
Too much power sanding is not good for soft wood like kauri , the shape and definition can be easily lost

Tiger
12th Jul 2010, 12:56 PM
Thanks, Rhys, good idea. Only tried power sanding once and it created more scratches that were difficult to remove.

RETIRED
12th Jul 2010, 12:57 PM
Too much power sanding is not good for soft wood like kauri , the shape and definition can be easily lostThis is not good Jock. I am agreeing with you.:D

Texian
12th Jul 2010, 01:30 PM
Sanding can indeed take longer than turning the piece. For terrible tearout you might want to start with coarser grit like 100 or even 80. The down side is that 80 grit sanding scratches can be about as difficult to remove as tearout and tool marks. Smoothest possible surface off the tool is obviously best.

TTIT
12th Jul 2010, 03:49 PM
.......Probably should get a list of timbers that I should avoid when doing faceplate work, if you care to mention any others I will make a note of them............My "Rule of thumb" is literally that - if you can dent the timber with your thumbnail, it's going to tear-out to some degree :C.
My way around it is to stop roughing well short of the final size and take progressively finer cuts until it's down to size.
On timbers like Kauri, the tear-out can be 2 or 3mm deep or even more so you have to take at least that much off in fine cuts before you start sanding :shrug:
Just my humble 2-bobs worth :U

Manuka Jock
12th Jul 2010, 04:11 PM
Probably should get a list of timbers that I should avoid when doing faceplate work, if you care to mention any others I will make a note of them.


If you go that way Tiger , you will have a very small wood pool to choose from :doh:
Just do what the rest of us do , find out what wood is good for what , push the boundaries , chuck a few attempts back into the firewood pile ,
and as TTIT says , improve the techniques of sharpening and turning , sanding and finishing .

Tiger
12th Jul 2010, 11:22 PM
If you go that way Tiger , you will have a very small wood pool to choose from

Generally I have found the hardwoods to be less prone to tearout and not requiring as much sanding. Maybe a list of the top 10 woods to avoid in faceplate work would be helpful :fisch:

Manuka Jock
12th Jul 2010, 11:26 PM
Generally I have found the hardwoods to be less prone to tearout and not requiring as much sanding. Maybe a list of the top 10 woods to avoid in faceplate work would be helpful :fisch:
Well you best start turning all sorts of wood and draw up your list .

Personally I prefer to develop my skills and have the world of wood at my feet :rolleyes:

Tiger
12th Jul 2010, 11:31 PM
Well you best start turning all sorts of wood and draw up your list .



I don't have access to all sorts of wood, but would like to know before I purchase any wood what timber would be best.

Manuka Jock
13th Jul 2010, 12:06 AM
Don't you get it ? There is no list .
Various factors come into play regarding tearout .
At the top of that list is the individual turner's skill .
Buy some pinus radiata and start practising .

Tiger
13th Jul 2010, 10:27 AM
It is generally known that some timbers are more problematic than others. All I am asking is which ones to avoid for faceplate work. I've had enough practice and don't intend spending years experimenting when people before me have already been through that.

The "list" is derived from people's experiences and that is what I'm hoping to find out.

So far we have Kauri and Meranti.

Manuka Jock
13th Jul 2010, 11:50 AM
It is generally known that some timbers are more problematic than others. All I am asking is which ones to avoid for faceplate work. I've had enough practice and don't intend spending years experimenting when people before me have already been through that.

The "list" is derived from people's experiences and that is what I'm hoping to find out.

So far we have Kauri and Meranti.
That depends on your ability , not the skills and experience of others .
If I were to ask the oldest member of our guild , he would draw up this list for you ,

:2tsup: ............. ............:2tsup:

:D,
but then he has been turning since 1942 :)

RETIRED
13th Jul 2010, 11:55 AM
Tony, a list really can't be drawn up.

A lot of people have trouble with pine and oregon, I don't because I have turned that much of it I have learnt how to get around its little problems.

Some love Sassafras, I don't because it can be a pain at times. Great for spindles but for face plate.....

You take all timbers as you find them and only time and experience gets you there.

Tiger
13th Jul 2010, 02:01 PM
, I haven't had too many problems with Pine or Oregon with faceplate work but had a lot of trouble with the Kauri piece that I was working on. Freshly sharpened scrapers get a good finish on Pine and Oregon but the Kauri was difficult and hence I had to sandpaper it out.

I had hoped to save myself the problem in future by not turning problematic timbers and was simply asking which were the main timbers to avoid. You do pickup bits of timber from here and there and it would be handy to know which timbers are not really suited to faceplate work so that you can use them for spindle work.

rsser
15th Jul 2010, 05:55 PM
Learning how to avoid tear-out on difficult wood is an investment worth making.

Tear-out is more likely on taking heavy cuts, with tool chatter or if the wood has started to flex.

If it's Ancient Kauri you were working on, I've had advice not to touch it with a scraper.

If it's not and you still have to scrape, then lap and polish the top of the scraper.

You can also try applying a coat or two of wax or sanding sealer before the finishing cuts to swell/stiffen the fibres.

Finally if you're sick of sanding and just have one or two small patches of tear-out, do them by hand or by gently stroking with a 1" power sanding pad blending it into the surrounding surface.

Tiger
15th Jul 2010, 06:49 PM
Hi Ern,

Not sure whether it's Ancient Kauri but despite repeated sharpening and some lapping I still found the piece difficult to scrape, I would get to a certain point and then different scrapers or angles of presentation would not remove the tearout that was left.

Only sanding helped to get a reasonable result but it took ages. I was pretty careful when I used the gouge but this wood you only need to look at and it tears out.

Manuka Jock
15th Jul 2010, 08:36 PM
Learning how to avoid tear-out on difficult wood is an investment worth making.

Tear-out is more likely on taking heavy cuts, with tool chatter or if the wood has started to flex.

If it's Ancient Kauri you were working on, I've had advice not to touch it with a scraper.


Ern , how did you get on with that piece of kauri you had ?

rsser
15th Jul 2010, 09:39 PM
It's on the tuit list MJ. Rough-out took about a year to dry in plakky; was showing signs of cracking so I whacked it in a bag. The top is rolled inwards somewhat so avoiding scraping will need some skilled gouge work!

Manuka Jock
15th Jul 2010, 09:54 PM
It's on the tuit list MJ. Rough-out took about a year to dry in plakky; was showing signs of cracking so I whacked it in a bag. The top is rolled inwards somewhat so avoiding scraping will need some skilled gouge work!
'Struth , that wet huh . Did they fell the tree while you were standing there ?
Skillful use of the 80 grit gouge too maybe :U
How is the colour of it , the figure ?

rsser
15th Jul 2010, 10:02 PM
This bit had come out of a bog. Certified 40k years old or somesuch.

There's a bit of figure there but it's hard to tell cos all the endgrain is furry; colour ... pretty ordinary but after sanding and finishing, who knows.

Tiger
15th Jul 2010, 11:27 PM
If it's not and you still have to scrape, then lap and polish the top of the scraper.



Never had much success with the diamond lap in raising a burr/sharpening the scraper. It does not come off much sharper after using the lap. The scraper straight off the grinder has given me the best results.

rsser
16th Jul 2010, 07:39 AM
You've misunderstood what 'lap' means.

Manuka Jock
16th Jul 2010, 07:45 AM
This bit had come out of a bog. Certified 40k years old or somesuch.

There's a bit of figure there but it's hard to tell cos all the endgrain is furry; colour ... pretty ordinary but after sanding and finishing, who knows.
Odd that they don't dry it before selling it .
Don't they export the stuff ?

rsser
16th Jul 2010, 07:49 AM
There was some back story to this that I barely recall; something about a local guy buying a load from NZ.

Manuka Jock
16th Jul 2010, 07:55 AM
There was some back story to this that I barely recall; something about a local guy buying a load from NZ. Oh , ok. I was thinking that you bought when you were over here last year .

Hey Ern , are you going to be anywhere near Dunedin this time ?

rsser
16th Jul 2010, 10:31 AM
Fraid not MJ; will spend time in the Craigieburns first, then W coast, Haast Pass, Wanaka, Lake Tekapo.

Might be able to see it from Hochstetter Dome?

Tiger
16th Jul 2010, 10:31 AM
You've misunderstood what 'lap' means.

I've found that the scraper burr doesn't last long when doing a finishing cut and find that I go back to the grinder frequently, I think what you are saying is use the grinder then a diamond lap to refine the edge, am I correct?

rsser
16th Jul 2010, 11:18 AM
Lapping (http://www.mini-lathe.com/lapping/lapping.htm)

Tiger
16th Jul 2010, 02:06 PM
Thanks Ern, actually did that to all my scrapers some time ago and it does help.

I got a bit confused with the terminology. I saw a youtube video of a woman using a diamond lap to make a burr on a scraper and confused the two.