Will This Work?

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Wheaties

Wheaties

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And if so, why don't more people do it?

Why not screw a scrap piece of wood to your faceplate, slap a sicky piece of sandpaper on it, then put a jacobs chuck in the tail stock with the correct size pen mill and square the blank that way? Is there some reason that this will not be effective? It seems the easiest, cheapest, and no messing with complicated jigs or crappy pen mills. Am I missing something?
 
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I have used a standard mandrel with a piece of adhesive backed sandpaper attached to the headstock end (just unscrew the stick portion of the mandrel, attach the sandpaper, and re-attach the stick). You can then use your milling sleeves to square up the ends or knock off the glue. But, you can get wobble if your tail stock is too tight or if your lathe is not in proper alignment. The system you described would suffer from even more wobble because of using the jacob's chuck.
 
Wheaties said:
And if so, why don't more people do it?

Why not screw a scrap piece of wood to your faceplate, slap a sicky piece of sandpaper on it, then put a jacobs chuck in the tail stock with the correct size pen mill and square the blank that way? Is there some reason that this will not be effective? It seems the easiest, cheapest, and no messing with complicated jigs or crappy pen mills. Am I missing something?
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Yea you are going to have to play that one out in your mind better and it will come to you.
 
bgibb42 said:
I've had this same thought, but I'm drawing a blank on what the drawbacks may be.
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Me too. I understand wobble may be an issue, but I can't think of anything other than that. I'll keep thinking. Might have to try it before I figure it out. Is it being so close to the center of rotation and sanding in opposite directions on either side of that blank? Not sure how that would be a problem though???
 
Depends on what "goodnuf" means for you --

That may depend on how much time, effort, and cost you have in the product you are seeking to make. "Goodnuf" means tight control on precision when I have a lot of time and money invested. Wobble is not a good word with $100 worth of parts and pieces plus time (think custom laser worked blanks with high end set of parts with custom work) and 1/2 day of time.
 
I guess I am confused as to the drawbacks as well. But then I have a hard time visualizing things in my mind. If the the faceplate is tight and the scrap wood is true and square and the jacobs chuck is tight and you use a sleeve with the mill, where is the wobble? Can someone help an old man out?
 
rjwolfe3 said:
I guess I am confused as to the drawbacks as well. But then I have a hard time visualizing things in my mind. If the the faceplate is tight and the scrap wood is true and square and the jacobs chuck is tight and you use a sleeve with the mill, where is the wobble? Can someone help an old man out?
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Well, I don't doubt the wisdom here, but I am going to try it this afternoon. Just to prove it to myself. I'll let you know how it goes.
 
Wheaties said:
Well, I don't doubt the wisdom here, but I am going to try it this afternoon. Just to prove it to myself. I'll let you know how it goes.
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I was going to try this last weekend in my dad's shop with a set of transfer punches, but we couldn't find the chuck for his lathe. I'm definitely interested to know how it works for you.
 
this does fall into the catagory of "What is good enough" but.
one you will have to make sure that the scrap wood is faced square with the head stock. I cannot recall any turning I have seen that would simply add a piece of wood to the mix and not face it. you then have to make sure the tail stock and chuck are in alignment with the head stock. an amount this is off with result in twice that much error in the squaring of your blank. My final thought (since I have not actually tried it) is that you are changing the forces on the pilot of the mill from a torque to a bend. I am not sure how much flex you will get but whatever it is will be an error from being truly square. this will also be true if there is any movement in the tail stock or the quill for any reason. Now nothing is perfect so in truth even a pen mill is only a degree of good enough. This is one of those gotta try it to know for sure ideas.
I am not at all sure what to expect by the fact the blank is not really held or clamped in any way. may just spin on the pilot and not cut at all.
 
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Daniel said:
this does fall into the catagory of "What is good enough" but.
one you will have to make sure that the scrap wood is faced square with the head stock. I cannot recall any turning I have seen that would simply add a piece of wood to the mix and not face it. you then have to make sure the tail stock and chuck are in alignment with the head stock. an amount this is off with result in twice that much error in the squaring of your blank. My final thought (since I have not actually tried it) is that you are changing the forces on the pilot of the mill from a torque to a bend. I am not sure how much flex you will get but whatever it is will be an error from being truly square. this will also be true if there is any movement in the tail stock or the quill for any reason. Now nothing is perfect so in truth even a pen mill is only a degree of good enough. This is one of those gotta try it to know for sure ideas.
I am not at all sure what to expect by the fact the blank is not really held or clamped in any way. may just spin on the pilot and not cut at all.
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Thanks for the tips Daniel! I was planning on facing the attached wood plate, and I know my headstock and tail stock are balls on. So we'll see this afternoon.
 
smitty said:
I have never had any luck with sanding in the middle of disc sander. I have to get away from the middle. But give it a try.
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I agree, but why I think it may be different than a disc sander is because on a disc sander you are using the top half of the middle. Not the whole middle. We'll see. I will report back.
 
Setup time

Unless I was doing a production run, the setup time would be too long for me, plus all the other things that I won't repeat.
 
ribanett said:
Unless I was doing a production run, the setup time would be too long for me, plus all the other things that I won't repeat.
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Thanks for the additional thought. Although I don't see time as an issue. It's just putting on a pre-made faceplate and putting the chuck in the tail stock.
 
You'll need to move the sandpaper for each blank, the center will get worn out very quickly. (the same has been noted on the sandermills) You are only going to be using the very center 3/4s of an inch. whereas on a regular disc sander, you can mover the blank to use the entire surface without moving the paper.


Getting a lathe point to point isn't hard, but you are going to need the tailstock to perfectly perpendicular to the faceplate. This may not be nearly as easy to accomplish. As Daniel said, 1 degree off and it's a 2 degree effect on the blank.
 
OK. HERE IT IS:

Tried it and I have to say it works VERY well. As Russianwolf mentioned, the sand paper wears out very fast and will need to be moved/replaced about every barrel. I had my lathe at 480 rpm and experienced no wobble. I did not turn the barrel I sanded, but it appears to be nearly perfect as far as squareness goes (as it should be). I think this would be a good finishing up way to square the blank as the sandpaper goes fast. I think I will use a disc sander free hand to get it close and this method to finish it off.
 
If I am picturing the two methods correctly. Ken is using the pen mill as a pen mill he has simply altered what the cutting edge is to sandpaper. the method by which the mill is then turned is not really an issue. the pilot of the mill is still directing the blank to an abrasive that is also mounted on the pilot.

in your case you are holding the blank with one instrument (tail stock) and the cutting surfaces (sandpapaer) with another instrument (headstock) the majority of the problems I see in your method are in assuring that these two instrumets are plumb level square and aligned to each other. Of course there is nothing wrong with shop equipment being tweaked to best possible condition. and at the very worst you might end up with nothing more than knowing your lathe is top dollar aligned.


Wheaties said:
One more thought before I actually try it:

How is the physics of it any different than what Ken did?
http://www.penturners.org/forum/showthread.php?t=50071
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Another issue but still on this topic, One issue I have with the pen mill. Particularly the 6 blade cutter head. is being able to see when you are at the edge of the brass tube. I have heard that using sandpaper, and I assume sandpaper by any method, that you are able to hear when you have reached the brass. is this true? I remember reading it only once and have never heard it mentioned again.
 
When you get to fine tolerances, there is a need to control the sources of variation -- have a tail stock and head stock and keeping them into tolerances will be a challenge - and as some have noted, that is not a production solution.

Machinists do not use precision process to hog off waste - and different precision is done on different gear -

Butch and others use the lathe with a skew -- great technique, especially for removal of extra stock -- roughing down, and the skill of the skew operator will determine the final product. Great production technique and well capable of achieving good results.

Piloted end mills and pen mills have great control of the angle from the center line and provide nice technique for hard homogenous materials - and are subject to chatter and tearing with not-so-homogenous-material like wood and mixed materials.

Sandpaper milling is hard to get absolutly even so you tend to get a fly cutter effect - the highest point does most of the cutting so you get grooves unless somethng moves to level it out. Sanding mills have the least of these and disk sanders have the most. (yes I have mounted lots of sanding disks and have measured runout). And making sure the table slot is exactly parallel to the disk on the cutting side takes time and gets knocked out of alignment easy on my gear. (dial indicator against the sander plate)

Yes, I used the backwards mill to do final finish on a $50 puzzle blank and considered a 15 cent sandpaper disk (1 inch commercial product) a good investment in precison. It was fast and easy.

Can a head stock driven, pilot controlled sandpaper mill be built and used - yup -- but it will not need to be very large in diameter, and it will tend to use a lot of small pieces of sandpaper. It should work as well as the backwards pen mill, or the sandpaper mills available if it is constructed to the same precision and controls.

In the final choices, each has to decide "goodnuf" and that will vary with the product and market and personal choices.

As always YMMV -- (your milage may vary)
 
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