Slitter Geometry

[Glenn]

I am glad you posted the photos. I have no idea why they are no longer part of the original thread. I have ask Andrew if it is possible to recover them from a backup. He is looking into the issue.

[nuge]

I have a few recent posts to this thread go missing. Why was I censored?

[Glenn]

Nudge

Out of the 188 posts in this thread I see none of your posts taken off line.

[nuge]

I definitely made posts to this thread that are gone. They were referring Brian's missing photos and were critical and raised questions about ownership and preservation of information. No rules were broke, no bad will intended, just the opposite. Criticism is a cornerstone of improvement.

 

 

We do not deny things are missing,  we stated that we did not remove them, no clue where they went or why the developers of the software like to use us a guinea pigs for bad code.

[Mike Romo]

Is there any news on the lost photos?  Could or would someone who saved them please make a post with them?  Thanks.

[Adam2519]

I went through some of the ones I had saved, ditched the images already posted by Eddie and Black Frog. Hope these are the right ones and they help.

 

Regards

 

Adam

 

 

[mitch4ging]

Thanks for posting all the pics guys! Now to make them...

[Mike Romo]

Thanks guys.  Now to go back the line them up with the text from the thread. 

[Eddie Mullins]

Thanks for posting those Adam. I'll add them to the collection : ) .

[Emower]

Can we get these photos back anyhow? I was trying to see some pictures of how people make their slitters, and they are all gone, even after some people have put them back after disappearing the first time.

[John McPherson]

[doubleipa]

That you for posting the pics John! I am still learning the trade and the pics are all gone from this thread so it is hard to understand all of what they are saying with out seeing some pics. 

[gote]

I am very grateful to peple who post losr pctures but the only one I can see are those posted by John. All others are URLs who lead to "sorry we cannot find it on this server.

Actually most URL's lead me out in to outer space.

[Bayshore Forge]

I second what Gote has said, it's difficult to understand how the pictures were important without being able to view them. If somebody has saved them all, it would be REALLY REALLY appreciated if they would repost. 

If this isn't possible then thank you for your time reading this

Brent 

[jeremy k]

The pictures that John McPherson posted in January are basically what this thread has been talking about.

[Frosty]

When he was up Brian Brazeal said you can make a simple die to set the angle on the slitter by welding a couple nuts to a plate so I did. Before I used my handy dandy new swage it dawned on me I have a swage block with a nice assortment of hex swages. I LOVE the slitter, works a treat.

Frosty The Lucky.

When he was up Brian Brazeal said you can make a simple die to set the angle on the slitter by welding a couple nuts to a plate so I did. Before I used my handy dandy new swage it dawned on me I have a swage block with a nice assortment of hex swages. I LOVE the slitter, works a treat.

Frosty The Lucky.

[Jason tojo]

Well I am glad That I have taken the time and have listened to the discussion here as it has opened my eyes to different views of this subject.  I would have certainly loved to have seen what was being talked about but the commentary was informative as well.  Thank you for the lesson of the day and I do hope to see more pictures up here on this subject soon.

Thanks, Noob

[anvil]

This is a great thread. Alas, I am unable with my smartphone to read it all. I can only read the first 4 pages, and page 9. I'm unable to go back or forward a page at a time.

 

So, this may have been covered elsewhere, but it appears to not.

Id like to add another solution, depending  on your personal esthetic or, perhaps structural needs.

The way described depends on one major criteria,,, that your over all bar length doesn't change due to each hole you make, or at least changes very little. To do this, the extra material needed to drift the hole must come from the sides of the drifted hole. Thus, they will be less than half the thickness of the parent stock. Meaning  the sides are drawn out In order to get the extra material to achieve your hole dimension and maintain a constant bar length.

What if your criteria for your esthetic or structural needs means you need all the thickness possible on the sides of the hole?

You must use a different process to achieve this. Your bar will shorten and the distance between holes will be where this happens. So, either by math or a test piece, you must learn how much loss on each end of the hole and add this to the distance between holes. Thus say you want two holes in a two foot bar. Your final bar length is to be two feet. You must double the above( for each hole) in-between holes and add that amount to the outside of each end of the bar.

Here's the process.

First you must use a slit chisel, not a slitting punch. The difference being a punch removes a button, a slit chisel loses no material.

The length of your slitting chisel depends on hole size. Say we want a 1" bar to pass thru a half inch bar. Your slitter length will be half the circumfrence of your final hole. Think of it as half of the circumfrence lives on each side of the slit.

Next we take a good yellow heat around the slit and upset the hole close to the proper diameter of the finished hole.

Final step is to drift, at a good yellow heat to achieve the final diameter(1"round in this case).

This will give you a full 1/4" thickness on each side of your hole. 

With no upset you will end up with very thin sides.

My chisel geometry is  different. This being an old thread, if there is an interest, I'll post pics.

Recognize, this is not a critique or an attempt to say one is better than the other, it's a way to create a completely different esthetic. Both are important and the more choices you have for any  detail, the more options you have with your design.

[Judson Yaggy]

6 hours ago, anvil said:

My chisel geometry is  different. This being an old thread, if there is an interest, I'll post pics.

Yes please.  More information is always good.  

In the architectural smithing realm, I learned to upset a hole after slitting and before drifting to compensate for side wall thinning.  It’s not about one perfect tool shape, but rather all steps in the process being complimentary to the final shape one wishes to accomplish. 

[anvil]

Snow tomorrow, but within the next few days I will post pics.

And what you described is how I do my pass thru's. I like the extra mass

[JHCC]

Is this technically “upsetting”? To be sure, you’re hammering on the end of the bar, but that’s to open up the hole rather than to thicken the workpiece, yes?

[genesaika]

@JHCC I guess that depends on how strictly you define upsetting. Is it only when you thicken the material by hitting on end? Or is it altering it in some way.

[Judson Yaggy]

6 hours ago, JHCC said:

Is this technically “upsetting”? To be sure, you’re hammering on the end of the bar, but that’s to open up the hole rather than to thicken the workpiece, yes?

It does both in this case.  

[JHCC]

34 minutes ago, genesaika said:

@JHCC I guess that depends on how strictly you define upsetting. Is it only when you thicken the material by hitting on end? Or is it altering it in some way.

If you broaden the definition of “upsetting” to “altering in some way”, you could theoretically use “upsetting” to mean “drawing out”, which doesn’t seem quite right. 

25 minutes ago, Judson Yaggy said:

It does both in this case.  

If you’re slitting a 1/2” bar and ending up with 1/4” on either side, what is getting thicker?

(I’m not saying you’re wrong, mind. I’ve just neither seen nor executed this exact procedure myself, and am just trying to visualize the mechanics.)

[Judson Yaggy]

John, when you punch or slit and drift a bar, the sides of the hole stretch and distort no matter what you do.  Punching removes at the very least a little slug of material, and while slitting should theoretically remove no material, both processes drag and distort the parent material into the hole with the tool.  This causes both a little thinning of the side walls and a little depression being formed on the tool side of the wp (if you work from both sides this is minimized but the effect of tool drag is none the less still visible).  

When you upset the area immediately around a punched or slit hole, the material will either upset or bend.  If your force vectors are as close as possible to the long axis of the wp the side walls of the hole will upset until they are thick enough or your hammering gets off center enough that the stock's resistance to upsetting becomes greater than it's resistance to bending.  

The art to the process is that if done well you can upset thin side walls for a few blows, correcting thinning, and then as things get fatter and stiffer, bend the cheeks away from the center of the hole.  In the same heat.  Bending is easier than upsetting, so you can do it at a lower heat. 

If your work piece is very thin, such as a piece of sheet metal, you will never notice the punch drag and deformation, and upsetting the hole will always bend the metal before upsetting due to the lack of resistance to your probably inaccurate force vector.  If your wp is quite thick, you will easily notice the punch deformation, but will find that it's easy to upset the parent stock back to something thicker.  The happy medium falls in to the stock sizes often worked in the decorative/architectural smithing world, 1/2" to 3" range and where visual appeal is very important.  There you can slit and drift, and upset the wp back to something that still looks like you magically parted the sea with no effort.