The Crispin Colloquy

Courtney,

I'm not a big fan of zippers at the back seam.

There is so much trama getting into the boot on the bottom of the zipper, where all if it's technology is, it's inevitable that there will be a need to do repairs in the years to come. And when you consider all the work that goes into a pair of handmades, it would just be a shame to have to do an ugly repair job with a patcher on a boot you were so proud of originaly, long before the boot was ready to be retired.

It could be that the split counter idea may make a difference, but ...

I hate to be a bummer and a wet blanket, but I guess it's a voice of experience. It's just that I've seen damage in this area on boots of this construction often enough, to make me think a side seam placement is much better, IMO.

Good Luck,
Paul

Cortney,
I would do it pretty much the same way as you describe but normally I don't use stiffener pockets, I let the lining go the full way down on boots.

On the boot above it seems like the zipper stops higher up and a split counter is not necessarily. One thing though about this way of construction, if the zipper stops to high you will have a problem entering the boot with probably a broken zipper as a result soon.

(Message edited by Janne_melkersson on February 26, 2010)

Thank you Paul and Jan-Erik,
It does seem like thats alot to ask from a zipper, thanks for the inside shoe repair insight.

Where do you get good zippers? Do you buy the unit the length you want or piece them together?

Seems like you would need to use a pretty heavy one to stand up to the abuse.

Courtney

Courtney

Years ago I had a pair of those bike boots with the zipper up the back and they were fine, zips are easily broken here, but in the wet, the water ran round the leg and down the zip straight into the boot.

It's not pleasant riding or walking with your boot full of water.

Tim

Some thoughts on using Copy-Carvers and the like for making lasts- these are thoughts, not things that I've actually put into practice. Hopefully I'm not repeating stuff that's been said already:

1st: From what I understand, if there is a mechanism to rotate the work like a lathe, I've heard they are not nearly as precise as one would need for a last.

2nd: With these types of machines it would be best to set aside the notion of using them like lathes for last making, and thinking of them more like milling machines.

Using a machine with 3 (up/down, left/right and forward/back - ?) axis, you are limited to zero undercuts in one operation. To make an object that is fully shaped in all axis, you have to break down the operations into two sections- top and bottom (or with a last- Medial and Lateral to avoid undercuts). There needs to be very accurate registration, so you can turn the master AND blank over and preserve the dimensions. When cutting (whether CNC or copy machine) the master has to have a sprue system to support the model and blank so it stays suspended at the end of cutting- these have to be manually cut away and smoothed after-wards.

I don't have any pictures, but the shop manager at the school where I teach cut a handgun model out of material using the CNC machine- at the end of the cycle, we have a block of material with voids around the model and dowel-like extensions across the voids, so the gun is suspended.

With some deluxe CNC machines, you can get purpose made rotational attachments that will hook into the system and be a fourth axis and act more like a lathe- but then your probably spending enough money to buy a dedicated CNC last mill/digitizer and speculation is moot.

I've seen a video of the Newlast system running and that was impressive- 6-axis, I think?

Erick

Eric,

Thank you for the explaination of the copy carvers. John suggested the radar carver which has a motorized rotational device.

I wish I could find something that is analogue.

John, had a great idea as to use index plates for rgistration points on one of these carvers. which would solve the rigistration issue.

I know that if it were the early 20th century and not the early 21rst century we would not be discussing CNC machine acuracy or lathes. Perhaps I could venture to say that we might be able to figure out an alternate way to the problems I am facing regarding last duplication. I am Sort of looking for a mix between modern motors and past success of the gilman as I sort of indicated in my opening question.

The problem I run into at our class at lastmakingschool.com in our intermediate class: http://lastmakingschool.com/classes/Intermediate%20Last%20Making.htm

It is a foundational footwear engineering course where we utilize a specially designed clay which has clay like behavior while very warm and the students can push around the volumes such as making a cone while taking away volume at the clip and placing it at the cone and so forth, but the clay is hard like wood when cooled at room temp. The students are learning a tactile knowlege,as it relates to shaping a last, therefore they are only allowed to use hand tools or mimimal power tools like band saw and the like if necessary. However, using a non shrinking last making clay, takes away the need to use most power tools any way. But when it comes to shaping the last, it must be a hands on activity.

We have methods of casting a last into HDPE once we are finished, however, I have had requests for the clay last to be copied into wood. Thus my question. I would like to carry this activity as a continued analogue activity and maintain the student's involvment. If you use scanning software and CNC lathes and the like, it removes the student from our objective of the class.

As the lastmakers clay is as hard as wood or similar, I belive it could be mounted onto a lathe or duplicator. However, once again, we are seeing the duplicator as an analogue power tool, thus, searching for a solution that is more anlague than CNC or computerized.

Anyway, i have had lots of resistance to the idea of analogue from this forum and I understand why. Why reinvent the wheel? We have the technology, why not use it? My simple asnwer is: tactile learning requires one to be in tactile communication with the item being formed. Shape and the feeling of shape is the very foundation to learning hand last making.

Our objective to this course is not only to preserve tradional/historical hand lastmaking, but also give a foundational course to those who want to go into computer technology last making such as romans or shoemaster.

If you take a look at what we are doing, teaching hand last making, than, it might make sence that we would want to complete the job with something closely similar as in somthing analogue. Something inbetween the gilman and the CNC. If you have any ideas of how we can strike this balance, i would greatly appreciate yours or others imput.

I wish I knew what 6 axis is.

-Marlietta

don't know how to explain 6 axis, but take a look at this video clip, and I think you will get the idea.
http://www.industryexchange.com.au/?p=255

John Lewis

John, your awesome!!!

You never cease to make me laugh! Where do you come up with these things?

This was so rediculous, I was able to understand 6 axis.

That was fun!
Marlietta, the easiest wat to explain 6 axis is this; a traditional machining table moves in 3 axis (x,y,z,)front/back,up/down,and left/right...relative to a fixed milling head.
a 4 axis does that plus has a milling head that moves up and down relative to the work
while a six axis machine adds two more planes of motion to the cutter position...

so to simplify if your work can move in 3 planes(axis) and your tool that is doing the work can also move in 3 planes (axis) you have a six axis machine.

Marlieta,

Think about something like this.

Use the gun carver as sort of shown in the picture with the 1/4" ball end mill. (www.wood-carver.com) Take 2 cheap wood lathes (http://grizzly.com/products/category.aspx?key=565000) like below and throw away the motors. Then take the pulleys the motors were driving and tie the 2 spindles together with a toothed belt and pulley. Doing so would bet both the pattern and block to turn together, especially if you added a hand wheel to one of them.

You could make the table out of something sturdy like www.8020.net structural extrusion for a minimal deflection sort of mounting.

Then it would be a very analog tool, but would turn out wooden lasts with minimal CNC or heavy duty machinery.





At least that is how I would start putting one together. There may be a less expensive carving copier than what is shown.

Paul

Paul
Good idea. When I spoke with Marlietta I described a couple of different ideas, but did not think of mini lathes. This would give you the ability to cut on both the X and Y axis, as well as do a rotational cut 360 degrees if you wanted. Now the thing would be to come up with a copy carver either buying or building, and figuring out how you were going to mount it
Good Job.
John Lewis

o.k just to invision Paul what you might be talking about, do you think this would be the same thing? http://www.radarcarve.net/?p=new

I like your inline proposal of the two lathes latched together, Another question is this, wouldn't the lathes have to be transverse of your inital black lines in your picture in order for the lathe position for the router/follower setup to work? .

If I am building the router frame any way according to the gemini patent number 5993123 http://www.freepatentsonline.com/5993123.pdf
as you show, perhaps setting up the copy carver and lathe so that the follower and router are not working side by side but in line as you propose?



Marlietta

John, Paul,

In the spirit of our discussion I found entry by bill tippit in 2003 as to how conventional last lathes work "http://www.thehcc.org/forum/viewtopic.php?t=2487


When a last is turned in a conventional lathe, the model rotates and is traced by a wheel that looks somewhat like an inline skate wheel. It rolls along the model and a separate arm on the lathe that contains cup cutters follows that path, cutting the block to copy the model. This arm can be adjusted so that you can cut different sizes that are proportionally the same shape. However, the conventional lathe is limited so that you can only turn 3 or 4 sizes away from the model before you start to drastically distort the shape of the last. Even with that distortion, 4 sizes is generally the maximum the machine can be adjusted. Thus, you need to make "accommodation" models every 3 sizes to extend the size run you are capable of turning.

There are basically two kinds of digitations processes. One, like the Compu-Last method I used at TLW uses the same contact method of a wheel but instead of having an arm with cutters follow the wheel, three digital encoders are attached that record, very precisely, the X, Y, and Z coordinates of the wheel at various locations along the path as the model is traced. Literally thousands of points are defined. Then, using special grading software, you can redefine those points and turn any size last with no distortion. Your only limitations are the physical length and width of the area you would put the block you are cutting into. There is no tool path distortion because the cutting is done using direct drive servo motors as opposed to "broken arm" tracing.

The way lasts are digitized on our new system is by the use of 2 cameras and 5 laser beams. The last is mounted upright it a "black box". It rotates and the lasers project onto the last and are captured by the two cameras. The entire last is digitized with even more points than were collected in the old contact method. This file can then be graded in our software to any size but much more than that, you can grade specific areas while holding others to their original measurements, adjust heel heights and toe springs, "cut" toes off one digitation and put them onto another for style changes, and do virtually anything that the model maker can do on the bench. In addition, the surface of the last can be flattened to get the shell for pattern design and grading or you can design the shoe or boot in 3D, directly on the last. You can create soles from the bottom surface of the last as well. When you grade the last, you can output the data to any of the CNC last making systems out there (Compu-Last, Newlast, Forma, etc.) or to any CNC milling machine or rapid prototype machine (such as 3D printers or Stereo Lithography machines)."

Marlietta
I think that using the little mini lathes, you could put them side by side with a toothed belt hooking them together as suggested, or put them inline, headstock to headstock and couple them together. I am starting to wonder if side by side might be the better method for smaller machines with less mass than the Gilman. There has to be some reason that all of these copy machines are side by side. Probably a few ween search of craigs list could come up with 2 used, cheap lathes of the same brand etc.
Then it should only be a matter of buying or building one of these copy machines

I am a little confused, what is the difference between a toothed connected lathe and the Gemini Gemini Deluxe Rotary Carving Fixture attatched to the Gemini Gunstock Carving Frame. Isn't it the same thing? I am not sold on this set up I am just posing the question for clearification. Isn't hooking two lathes up in this mannor the same as the bicycle chain Deluxe Rotary Carving Fixture attatched to the Gemini Gunstock Carving Frame set up?

Grisley lathe $215 X 2 equals $430


9" gemini Rotary Carving fixture $950
Gemini Gunstock carving frame $1950

With the carving frame, you still don't have support at both ends for the master and blank. With the lathes, both the master and blank are supported on both ends. What am I leaving out?
John L

John,

I didn't mean to sound "blonde" In our conversation yesterday, I totally got what you were getting at. I understood the concept of both ends being supported. i like the lathe idea, When i saw the video of the gemni which is the same as the radar carver which is the same as the capy carver, all these duplicators are all the same. They have a router on one side and a copy/ follower on the other. Now you make an EXTREMLY GOOD POINT, regarding price. The lathe isn't that expensive for two. I was only posing the question for clarification. Because the the rotary carving fixture DOES support on both ends! thus you are not leaving any thing out, infact, you have been VERY HELPFUL along with paul and the others. I just wonder I can't be the only one who has asked if there was a way to duplicate our own lasts cost effectivly, can I be?

On the other hand, maybe one doesn't need to take the motors out of both lathes, maybe one leaves the motor in one of them. Chain hook the two lathes together as paul suggests and place a scoop/cup cutter on one and a follower wheel on the other. Have an over frame similar to the copy carvers. and turn a last. I would love to post what I mean in pic, How do I load a pic into my post????

- Marlietta S

By the way, as Bill discribes it and the discription of the gilman. Because they are inline as apposed to side to side, You can posiiton the follower wheel in carefully set positions so that the duplicate last will be smaller or larger in grade. this is true because how the revolution to pentegragh motion happends on an inline.

When a last is turned in a conventional lathe, the model rotates and is traced by a wheel that looks somewhat like an inline skate wheel. It rolls along the model and a separate arm on the lathe that contains cup cutters follows that path, cutting the block to copy the model. This arm can be adjusted so that you can cut different sizes that are proportionally the same shape."

Here is a random thought.

It seems to me that the major challenge in all of the duplicators discussed is ensuring the rigidity of the system, in particular making sure the cutting head tracks the tracing head accurately. Given that, in all these systems, the cutting head is on the end of an arm, which is in turn attached to some sort of a carriage, it will be difficult to reduce or eliminate unwanted vibration and/or distortion of the position of the cutting head relative to the original/tracing head.

One thing all of these approaches seems to have is that the tracing arm and cutting head move in all three dimensions, while the original and the copy don't move at all.

So, rather than that approach, might one fix the cutting head and tracing head in a fixed/highly rigid position and then instead move the original and the item being cut? Given that the original and the copy block are more massive and inherently pretty dimensionally stable, and also that they can be attached to a stable structure at both ends (heel and toe), wouldn't it be easier to reduce variance by moving these and keeping the cutting head fixed, or at least making it only move in one dimension (e.g. vertically)?

I could see two approaches: one would be a system that would require turning the original and the copy over after completing the top half of the carving; in this instance, the original and the copy would be on a 'sled' that would allow the cutting head to 'nibble' away the copy by moving the original and the copy in both of the horizontal dimensions while the tracing head and the cutting head only move vertically. After doing the top half, you'd have to rotate the original and the copy 180 degrees to do the bottom/undersides (including undercut areas) of the lasts.

The second approach would be similar, in that the tracing arm and the cutting head would only move vertically, and the original and the copy would be able to slide back and forth in one dimension (likely along the length of the last), but they would be on lathe-like rod(s) that would allow you to rotate them, either after making a pass (if they are side by side and hence coupled by a toothed belt) or even while making a pass if they are aligned in tandem on a single rod. With the ends fixed, you could even do a 'rough' copy with a more aggressive cutting head, then do a second pass with a finer head for a smoother finish.

Lance

Hi Lance,

thanks for your input on this. i was hoping you'd join in.

Good point. I like the fixed position. It does solve many issues.

In what you are imagining, are you imagining the cutter and follower be on the side like the gilman, or are you imagining the cutter/follower be on top? where were you imagining the cutter and follower to be?

On your second idea are you proposing that the cutter and follower are spring loaded so they move up and down while the sled is holding them steady?

On your second notion, are you proposing a shish-cobob sort of set up? how would the two model and blanks be held to turn as one unit? I understand the toe and heel end would be in a clamped position in both the model and the blank, but how would they turn in unison, in your imagination?

Marlietta
You were not sounding "blond" at all. I just restated mostly for everyone else about the support issue. My comment "what am I leaving out" was not directed at you, it was a general question to the group asking if they had any ideas or saw any thing I was overlooking. The whole thing has been fun and the interaction of everyone has been good and spirited. Hopefully the end result will be a econominal and accurate way to duplicate lasts.
Lance's idea about having the cutter head in one place and moving the master and blank is not a bad idea also. Kind of like using a vertical mill. The items are secured to the table and the table moves right and left and backward and forward while the head stays in one place.
Compound slide tables are not that expensive.

Marlietta
The picture thing is covered in the formatting section. basicly you type in the word image followed by \ Then { your image here}. I don't know if I am doing the your image thing correctly, but I have been typing in the path to the photo and the file name and it seems to work.
Then as you keep clicking he preview/post box, it will ask you the name of the file you want to publish. You browse to it and click and it should appear. Make sure that the picture is not too large.

O.k. I am getting jelous here, someone please tell me how they got their pics up?

John, how did you get that pic on your post, I WANT TO ADD PICS TOO...

Marlietta
check your email. I tried to explain posting there.