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View Full Version : How do you like to mount?



Frank&Earnest
3rd Jun 2010, 06:26 PM
Unless its large size makes it necessary, I do not like screwing the blank, either to a faceplate or a screw chuck, the main reason being the limitations imposed on the blank because of the need to remove the deep holes of the screws. My preferred method so far was to drill a recess with a Forstner bit (first photo) and mount on the chuck in expansion mode. It never gave me any trouble but it may be a less safe option than a tenon and some people hate this method with a passion, as it emerged in another thread.

Last weekend I saw Tim Skilton cut a groove inside a bowl to reverse mount, and that gave me the idea of drilling a groove around a tenon instead of a recess. This has three advantages: much easier to cut with a hole saw than with a Forstner bit; makes the haters of expansion mounting happy :wink:; and if the tenon fails, the recess for using the expansion mode is still there.:D

So I made the jig you see below using a 2.5" and a 2" hole saw stacked (the whole set cost me only 12 bucks at the last show, IIRC) which produces a groove wide enough to fit the thickness of the jaws and a tenon of the most effective diametre (about 47mm for the standard jaws of the Supernova 2, but they are all about the same, I think). The other dimension to optimise is the length of the tenon, which has to be equal to the depth of the jaws minus a small clearance to ensure that the blank sits evenly on top of the jaws. In this case about 9mm. This is achieved by removing the central drill and replacing it with a centring point/depth gouge fashioned by sharpening a rod of the appropriate diametre and epoxying a collar around it. After paring off the waste between the cuts the blank is ready for mounting.

Stacking the saws implies that the internal cut is slightly deeper than the outside cut, which does not seem to be a problem. Of course with any drilling method it pays to check with a level that the hole is orthogonal to the surface, which might require sitting an irregular blank on a couple of wedges before drilling.

Harry72
3rd Jun 2010, 08:29 PM
Not a bad idea Frank, you'd need a fair amount of torque running two cups at the same time.

Personally I just glue on a block of jarrah with a tennon precut or a block of jarrah with my lathe sized thread tapped into it(Beall Tools tap for nova lathes)

mkypenturner
3rd Jun 2010, 10:41 PM
if its under 10 " round and 2" thick i just stick it against the chuck and bring tail stock up and tighten and turn about 1200 rpm and turn a tenon to suit the chuck

tea lady
4th Jun 2010, 12:09 AM
But you've still got the little hole in the middle. :pi: Just put it on the screw chuck and be done with it. :shrug: You don't have to have it going the full depth of the screw. Put a shim of ply on the screw first and face it off flat then screw the blank on.:cool: I've only had softer woods strip their thread. :shrug:

hughie
4th Jun 2010, 12:16 AM
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Just put it on the screw chuck and be done with it. :shrug: You don't have to have it going the full depth of the screw. Put a shim of ply on the screw first and face it off flat then screw the blank on.:cool: I've only had softer woods strip their thread. :shrug:


Yep thats the way I do it, except my shim is a piece of stainless 3mm plate. I find such a backing plate give support to the screw and prevents any side movement and weakening the screw grip.

Frank&Earnest
4th Jun 2010, 01:20 AM
But you've still got the little hole in the middle. :pi: Just put it on the screw chuck and be done with it. :shrug: You don't have to have it going the full depth of the screw. Put a shim of ply on the screw first and face it off flat then screw the blank on.:cool: I've only had softer woods strip their thread. :shrug:

The hole in the middle is only a couple of mm deeper than the tenon, just enough for the point to protrude into the centre punch when starting the cut. That makes it 11-12 mm total, not enough for holding a decent size unbalanced blank with a single screw. Which was the point, but as I premised it is a matter of preference.

If the choice is between drilling methods I think I could reasonably argue that this is intrinsically the best one, but of course the comparison with any other methods requires the consideration of a lot more variables.

tea lady
4th Jun 2010, 01:41 AM
But You still have to turn all that stuff off the base. :shrug: Just use a screw chuck or if the blank is really too misshapen screw it to a face plate. Personally I haven't got a drill press, just a hand held drill and I would not be able to drill double holes with a hole cutting saw. And if I manage one, I certainly wouldn't manage a whole stack of them fo ra day's work. You just have a hole with vertical sides anyway, not a true tenon with an undercut dovetail. It will just pop off the first catch or even big decent cut you take. :shrug: But if it works for you, that's fine. There are many ways to skin a cat.

I have had great success recently mounting my bowl blanks between centers and turning the outside shape including a foot to grip in the chuck in compression mode. This works really well for deep bowls. And for quite misshappen wobbly ones too. Haven't tried it with flatter platter shapes. :shrug: I also imagine it would be quite easy to cut a slot that way to tak a chuck in expansion mode too, with undercut dovetail and all. Now I have Cole Jaws it a simple matter to make a nice bottom afterwards.:cool: This method is really fast. Requires no pre-drilling, and minimal marking of the centers. And I have never had one fly around the shed. (Except if you count that spalted one that was mostly air anyway. :rolleyes: )

Frank&Earnest
4th Jun 2010, 02:33 AM
Yes, making the tenon between centres is the easiest solution, the problem I had with it is that big unbalanced blanks keep slipping because the spurs eat the timber away. Also, it needs to be cut away afterwards, it can not be used as the foot unless the bowl is very small, which would make this mount irrelevant anyway. As a minimum this groove allows me to hold the blank between centres better than the spurs, but it would have to be a really big catch to dislodge a properly fitting "vertical" tenon anyway. Or "vertical" recess in expansion mode, for that matters. I am not into turning as an extreme sport. :D

oldiephred
4th Jun 2010, 10:23 AM
check with a level that the hole is orthogonal to the surface

Don't mean to show my less than average brightness nor to be critical but please explain "orthogonal" and how to check it with a level:?

NeilS
4th Jun 2010, 12:07 PM
Some production bowl turners (eg Robo Hippy) prefer to cut a recess in the blank for mounting, others like Raffan prefer to use a screw chucks (and shim on shallow blanks as TL and Hughie have described). Some of us continue to use faceplates, while others fiddle around with mounting between centres. Each to their own, but it's always good to have our orthodoxy challenged.


.... I do not like screwing the blank, either to a faceplate or a screw chuck, the main reason being the limitations imposed on the blank because of the need to remove the deep holes of the screws. .

On shallow blanks use shorter, but fatter, screws, and more of them.
Galvo hex headed screws work quite well.
Regular wood screws are too thin and prone to snapping.
May need to drill out faceplate holes to accommodate the thicker gauge screws.
If needed, drill a few extra screw holes in faceplate to increase grip.
Countersink screw holes on blank side to accommodate lifted wood fibre.

Haven't done it myself, but chiseling out the wood between the two hole saw cuts looks like it would be time consuming. Getting the bottom of the rebate flat to evenly seat the jaws would be a challenge, at least for me...:rolleyes:. An adaptation of an adjustable hole saw cutter like this (http://www.holesaws.com.cn/products/holesaws/adjustable/adjustable.htm) might speed up the job. If the top of the blank is flat, power routing is another option.... and a dovetail bit could be used to create the correct dovetail angle. Hmm... this is starting to sound like flat wood work to me...:U

.....

tea lady
4th Jun 2010, 01:50 PM
If the top of the blank is flat, power routing is another option.... and a dovetail bit could be used to create the correct dovetail angle. Hmm... this is starting to sound like flat wood work to me...:U

.....a dovetail bit could be used to create the correct dovetail angle. Now there's a good idea. :2tsup:Could be useful on a big flat platter blank.:cool:

brendan stemp
4th Jun 2010, 02:10 PM
Thanks for sharing your idea with us F&E. It certainly has merit but I'm with Tea Lady on this one. A screw chuck is just sooooooo easy. One hole drilled, simple. I have turned up to 500mm using a screw chuck. And I have never had any problems with getting rid of the hole that is made for it.

Frank&Earnest
4th Jun 2010, 03:17 PM
Thanks for sharing your idea with us F&E. It certainly has merit but I'm with Tea Lady on this one. A screw chuck is just sooooooo easy. One hole drilled, simple. I have turned up to 500mm using a screw chuck. And I have never had any problems with getting rid of the hole that is made for it.

I have no doubt that the screw chuck is the easiest solution and works well with deep bowls. Part of the issue will always be what one is more comfortable with, for example I am comfortable with paring the waste, Neil is not (excellent idea the circle cutter Neil, thanks, must try it- it could be more effective than my jig). My limited experience does not allow me to assert with confidence what works better with what, my empirical argument is only that on any blank more than 10" wide and less than 4" thick the depth of the hole necessary to hold it securely is, for my taste, limiting too much my design options. :dunno:

Frank&Earnest
4th Jun 2010, 03:21 PM
check with a level that the hole is orthogonal to the surface

Don't mean to show my less than average brightness nor to be critical but please explain "orthogonal" and how to check it with a level:?

Sorry mate, did not want to be a p***k, it's just what one is used to. I meant that the hole has to be at 90 degrees with the top surface of the blank, and because the bottom for example of a half log is round, you have to sit it on the drill press table on some wedges and check with a spirit level that it is reasonably flat.

Frank&Earnest
4th Jun 2010, 04:42 PM
Neil,
by "Galvo hex headed screws work quite well." do you mean the short ones for colorbond fences with the metal cutting point? The roofing ones that go into timber battens are 40-50 mm long, a bit too long IMHO. Or you had something else in mind?

(screwing all those screws in and out seems to me more time consuming than my paring, though...:) )

It always catches me. Have you noticed that if there is not a space between :) and ")" the software decides that you meant to put in the icon for ROFL?

RETIRED
4th Jun 2010, 07:50 PM
Neil,
by "Galvo hex headed screws work quite well." do you mean the short ones for colorbond fences with the metal cutting point? The roofing ones that go into timber battens are 40-50 mm long, a bit too long IMHO. Or you had something else in mind?They come in sizes from 16mm-150mm. I use them in preference to all others.

(screwing all those screws in and out seems to me more time consuming than my paring, though...:) )A cordless drill does it in about 15 seconds for all of them. No setup time to drill or shim up blank to get a level hole.

It always catches me. Have you noticed that if there is not a space between :) and ")" the software decides that you meant to put in the icon for ROFL?For the last 30 years I have turned plates and bread boards 3/4" or 20 mm thick on a single screw that only goes in 1/4". It is easy to get rid of the hole by turning it out.

The faceplate or screw chuck is generally "the inside" of the bowl and has to be removed any way.

hughie
4th Jun 2010, 08:56 PM
The faceplate or screw chuck is generally "the inside" of the bowl and has to be removed any way.



Yep, thats the way I do it and it works fine. This piece is held on by a screw chuck and from memory never had a problem.

NeilS
4th Jun 2010, 09:53 PM
Neil,
by "Galvo hex headed screws work quite well." do you mean the short ones for colorbond fences with the metal cutting point? The roofing ones that go into timber battens are 40-50 mm long, a bit too long IMHO. Or you had something else in mind?

(screwing all those screws in and out seems to me more time consuming than my paring, though...:) )

It always catches me. Have you noticed that if there is not a space between :) and ")" the software decides that you meant to put in the icon for ROFL?

has pretty well covered it in his post. I use the Sheet Metal ones on the top right here (http://www.boltdepot.com/Fastener-Information/Type-Chart.aspx). They have a short slot cut into the tip (not shown) that helps drill and screw at the same time, but not to be confused with the self drilling style, shown second down on left.

Yeah, that ROFL thing is a bit annoying.

.....

Harry72
5th Jun 2010, 12:12 AM
Here's a glue block and the tap involved:U

Very easy to use, just got to wait for the glue to dry too use it and you lose no blank depth at all.
Good for making strops too :2tsup:

Frank&Earnest
5th Jun 2010, 01:13 AM
Here's a glue block and the tap involved:U

Very easy to use, just got to wait for the glue to dry too use it and you lose no blank depth at all.
Good for making strops too :2tsup:

Yes, it is a good solution and I have used it at times. The only way I have found to center it well, though, is to mark on the blank a circle as wide as the sacrificial block/faceplate and position it. I bought a hot glue gun for the purpose but either it was defective (el cheapo, not surprising) or I could not work out how to get it to squeeze out the glue, I just gave up, must try again. Drying time and cutting out PVA does not appeal to me, but I have on the bench a blank started just that way because I could not see a better option. It was meant to be my entry to the box challenge before everything else in my life took priority. :rolleyes:

Given the consensus about the screw chuck I really must try harder. I noticed your openness, Neil, although you also prefer that.:) Thanks for the advice. The blank in the photo is one of 4 cut out of a log of red ironbark, I'll try various methods for comparison.

, thanks for the advice. Two further questions, please:

- to get the screws into hard wood, wouldn't it be necessary to predrill the holes?

- 1.4" is quite deep, are you saying that you start from a 3" blank to get a 3/4" thick plate? I don't think I got it.

RETIRED
5th Jun 2010, 09:30 AM
yes, it is a good solution and i have used it at times. The only way i have found to center it well, though, is to mark on the blank a circle as wide as the sacrificial block/faceplate and position it. I bought a hot glue gun for the purpose but either it was defective (el cheapo, not surprising) or i could not work out how to get it to squeeze out the glue, i just gave up, must try again. Drying time and cutting out pva does not appeal to me, but i have on the bench a blank started just that way because i could not see a better option. It was meant to be my entry to the box challenge before everything else in my life took priority. :rolleyes:

Given the consensus about the screw chuck i really must try harder. I noticed your openness, neil, although you also prefer that.:) thanks for the advice. The blank in the photo is one of 4 cut out of a log of red ironbark, i'll try various methods for comparison.

, thanks for the advice. Two further questions, please:

- to get the screws into hard wood, wouldn't it be necessary to predrill the holes? i generally don't as they are self drilling. Be careful that you use wood, not metal screws. Metal screws don't grip as well. Damhik.:wink:
However, sometimes the wood pulled "up" by the screw will not let the faceplate seat flat. In that case i generally remove the plate again and countersink the holes but it still only takes a minute or so.

- 1.4"(oops,:- should read 1/4".edited my original post) is quite deep, are you saying that you start from a 3" blank to get a 3/4" thick plate? I don't think i got it.hth.

Frank&Earnest
5th Jun 2010, 02:38 PM
For the last 30 years I have turned plates and bread boards 3/4" or 20 mm thick on a single screw that only goes in 1/4".

:oo::oo::oo: Do you walk on water also? Can mere mortals do that?

Or was the diametre of the plate 1" ? :D

Now I definitely have to try harder with this method. Thanks .

All this now begs the question: what is the maximum size of the blank I could mount on this? http://www.woodworkforums.com/f8/mini-screw-chuck-51113/

BTW, I tried again the glue gun today and it worked. Maybe last time I had left it on too long. :dunno:

NeilS
6th Jun 2010, 03:45 PM
:oo::oo::oo: Do you walk on water also?

Haven't seen walk on water, well not yet. But have seen him walk on more shavings than most people can produce in a minute....:U

All this now begs the question: what is the maximum size of the blank I could mount on this? http://www.woodworkforums.com/f8/mini-screw-chuck-51113/

Keep that dainty little screw chuck for bottle stoppers and use the more substantial screw that will have come with that 100mm chuck for your bowl blanks.



.....

Frank&Earnest
7th Jun 2010, 12:57 AM
"Keep that dainty little screw chuck for bottle stoppers and use the more substantial screw that will have come with that 100mm chuck for your bowl blanks."

Or the bigger one that came with the SN2 ... my sentiments entirely.

But if can turn a plate on a 1/4" long screw, he could turn a 20" bowl on that 1" screw...:D

RETIRED
7th Jun 2010, 09:00 AM
"Keep that dainty little screw chuck for bottle stoppers and use the more substantial screw that will have come with that 100mm chuck for your bowl blanks."

Or the bigger one that came with the SN2 ... my sentiments entirely.

But if can turn a plate on a 1/4" long screw, he could turn a 20" bowl on that 1" screw...:DHave turned 600mm platters on a screw chuck.

The Woodfast one. The Nova and Vicmark leave too big a hole.:D

Frank&Earnest
7th Jun 2010, 04:19 PM
Have turned 600mm platters on a screw chuck.

The Woodfast one. The Nova and Vicmark leave too big a hole.:D

OK, OK, I got it. No need to turn the screw any further... :D:D:D

robo hippy
8th Jun 2010, 04:12 AM
I do use a forstner bit recess in the top of the bowl to turn the outside, and a tooled/dove tailed scraper to form a recess on the bottom of the bowl for coring and finish turning the inside of the bowl. Just the fastest and most simple method for me (efficiency is intelligent laziness). It really doesn't seem to make a whole lot of difference that the sides of the drilled recess are straight (not dove tailed. It holds enough to keep the blank secure for heavy roughing. I do make it 1/4 inch plus deep, deeper than the dove tailed one I tool into the bottom for turning the inside. I don't think you could get an accurate recess with a forstner bit in a hand held drill, especially if the bit is getting dull as they will want do wander off course, and you really want the sides perfectly straight. Any drill big enough to handle the hole saw blades, would probably cost about as much as a good drill press. There are also drill bits with a grub screw in the center to pilot the bit, but again, it takes a big hand drill to run it, and the grub screw can pull the drill bit into the wood too fast.

While I know the screw chuck works, I just never trusted it. A small screw to hold a big blank??? With the depth of the screw, I wouldn't be concerned about removing the hole. The last core is usually shallow enough that it isn't worth the effort to turn, so I just turn it out. I have one that fits into my big chuck, but, just never learned to use it well.

I would guess that a router bit could be used to make the recess. I measured once, and my jaws on my Vicmark are about 7 degrees, which is the common angle used in flat work dove tails.

The stacked hole saw blades are an interesting concept, but looks like too much work for me.

robo hippy

Frank&Earnest
9th Jun 2010, 02:09 PM
I do use a forstner bit recess in the top of the bowl to turn the outside, and a tooled/dove tailed scraper to form a recess on the bottom of the bowl for coring and finish turning the inside of the bowl. Just the fastest and most simple method for me (efficiency is intelligent laziness). It really doesn't seem to make a whole lot of difference that the sides of the drilled recess are straight (not dove tailed. It holds enough to keep the blank secure for heavy roughing. I do make it 1/4 inch plus deep, deeper than the dove tailed one I tool into the bottom for turning the inside. I don't think you could get an accurate recess with a forstner bit in a hand held drill, especially if the bit is getting dull as they will want do wander off course, and you really want the sides perfectly straight. Any drill big enough to handle the hole saw blades, would probably cost about as much as a good drill press. There are also drill bits with a grub screw in the center to pilot the bit, but again, it takes a big hand drill to run it, and the grub screw can pull the drill bit into the wood too fast.

While I know the screw chuck works, I just never trusted it. A small screw to hold a big blank??? With the depth of the screw, I wouldn't be concerned about removing the hole. The last core is usually shallow enough that it isn't worth the effort to turn, so I just turn it out. I have one that fits into my big chuck, but, just never learned to use it well.

I would guess that a router bit could be used to make the recess. I measured once, and my jaws on my Vicmark are about 7 degrees, which is the common angle used in flat work dove tails.

The stacked hole saw blades are an interesting concept, but looks like too much work for me.

robo hippy

Oh what a difference does a "b" make! :D Thank you very much Robo, your confirmation is very uplifting for me. Intelligent laziness rules! :D

One thing I checked after this discussion is the shape of the jaws I am using. None of them is really "dovetailed" after all, they are all straight with one ridge or two smaller ridges on the outer rim for gripping. The market sorts out these things very quickly, so one would think that if dovetailing was a big advantage the makers would have obliged.

robo hippy
9th Jun 2010, 04:33 PM
Yea, it is robo hippy, as in robo cop. Came from me twirling my hammer around my finger and trying to get it into my tool belt loop like the old movie Robo Cop. I was wearing a big leg brace at the time, and one guy on the crew shouted "Hey, it's robo hippy!", and I liked it.

I have the Vicmark chucks. Both Nova and Oneway have dove tailed jaws for their chucks now. They do hold better than the straight jaws, with the exception of the ribbed ones. Dove tail joints have been used in flat work since about day one because of their mechanical advantage.

robo hippy