XTant - Bringing the IBM XT into the 21st Century: Part 2

[Melvang]

I will make an IC then later tonight

I would check with The Beast about this as well.  Wcass mentioned that he had a plate cut for this project for $30.

The flip side is getting the plates ran through a slip roller.  That is probably doubling the cost itself in its own right.

I checked at some local places with slip rollers and that was pretty much the case.

Yeah for low volume runs (these places consider 1000 pieces about the bottom end of large volume) the setup time is about 9 times the production time.

[dorkvader]

https://geekhack.org/index.php?topic=69344.0

^GB link for prototype plates cut and rolled. May not appear right away until it's approved.

note: based on my measurements of an actual XT plate (5" chord length and 0.25" bend depth) we are going with a bend radius of approximately 15". The XT case is tolerant of different bend radii so it should work with no issues even if it's off a little.

The shop we are going with should have a pretty quick turnaround on this, so I can test it and get XTant prototype #3/10 working.

[vivalarevolución]

https://geekhack.org/index.php?topic=69344.0

^GB link for prototype plates cut and rolled. May not appear right away until it's approved.

note: based on my measurements of an actual XT plate (5" chord length and 0.25" bend depth) we are going with a bend radius of approximately 15". The XT case is tolerant of different bend radii so it should work with no issues even if it's off a little.

The shop we are going with should have a pretty quick turnaround on this, so I can test it and get XTant prototype #3/10 working.

That link isn't working for me.

[dorkvader]

May not appear right away until it's approved.

That link isn't working for me.

Link should be working now.

[Hypersphere]

I have contacted a place about getting custom XTant plates made. He has quoted $70/ea for a small run of 5. Does anyone else with a prototype kit want one?

Yes, I would be very interested. Please let me know what I would need to do. Thanks.

[dorkvader]

I have contacted a place about getting custom XTant plates made. He has quoted $70/ea for a small run of 5. Does anyone else with a prototype kit want one?

Yes, I would be very interested. Please let me know what I would need to do. Thanks.

I have already marked down your interest. You would just need to pay for the plate and shipping. (and provide me your address of course, but all in due time.)

[0100010]

5" chord with .25" depth gives me a 12.625" radius.

[dorkvader]

5" chord with .25" depth gives me a 12.625" radius.

yes, I thought it was closer to that. I'm checking now.

[Melvang]

5" chord with .25" depth gives me a 12.625" radius.

yes, I thought it was closer to that. I'm checking now.

Want me to check my XT and my AT?

[0100010]

5" chord with .25" depth gives me a 12.625" radius.

yes, I thought it was closer to that. I'm checking now.

Want me to check my XT and my AT?

Yes, please! 

[Melvang]

5" chord with .25" depth gives me a 12.625" radius.

yes, I thought it was closer to that. I'm checking now.

Want me to check my XT and my AT?

Yes, please! 

I can do that tonight.  Though the numbers on my AT might be a touch off.  I tweaked the top barrel plate a touch.  From the numbers I measure off my plates, I will figure up radius on the curve.

[dorkvader]

Want me to check my XT and my AT?

No I'm sure of my measurements of chord length and arc depth, but the radius is calculated from those.

Chord length was 5" exactly. Depth of bend was 0.25" exactly (or as close to it as I can measure). The exact output doesn't have to be *too* precise)

Turns out that calculating the bend radius from those measurements proved to be a challenge. I just plugged it into wolfram alpha and got 12.625 as well.

I need to open up my AT anyway for modding, so I can measure it as well if anyone wants.

[Melvang]

Want me to check my XT and my AT?

No I'm sure of my measurements of chord length and arc depth, but the radius is calculated from those.

Turns out that calculating the bend radius from those measurements proved to be a challenge. I just plugged it into wolfram alpha and got 12.625 as well

Another one that is interesting to figure is the area between that chord and the circumference without  knowing the angle from the center to the endpoints on the chord.

[dorkvader]

Want me to check my XT and my AT?

No I'm sure of my measurements of chord length and arc depth, but the radius is calculated from those.

Turns out that calculating the bend radius from those measurements proved to be a challenge. I just plugged it into wolfram alpha and got 12.625 as well

Another one that is interesting to figure is the area between that chord and the circumference without  knowing the angle from the center to the endpoints on the chord.

it's a pain to simplify, but from the depth of arc and chord length (or arc length) you can calculate the bend radius and get the angle from there. The angle can be had exactly using that, then the area can be had from either : derive it yourself with calculus (what I wolud do on an exam) or look up a folmula / go make a CAS do it for you (what I would do in real life).

For reference, here's the eq for what I needed (not area).

a = depth b= chord length R=radius of curvature:
Pythagoras: R^2 = (b/2)^2 + (R-a)^2
R = (0.25 b^2 + a^2) / (2 a)

[jacobolus]

None of these things take calculus, it’s all pretty simple geometry problems. I would write out the reasoning right here, it only takes a couple minutes, but drawing diagrams on paper and first scanning/photographing then uploading them somewhere is a pain in the ass, and I can’t be bothered. :-)

[dorkvader]

I'm just gonna photograph the paper I used

edit:
*(left out a parenthesis, so sue me)

Now that we have all the serious hardcore maths out of the way, we can get these plates made and everyone will have XTants hooray!

[Melvang]

I'm just gonna photograph the paper I used

edit:

Show Image

Now that we have all the serious hardcore maths out of the way, we can get these plates made and everyone will have XTants hooray!

Aside from me not having a PCB. 

For future prototypes and such, would it be possible to have the navigation block set up as a 5xwhatever matrix?  This way we can fill those open spots in and have it look stock.

Just out of coursity, what is the actual width of the main block in terms of units, excluding the pair of columns for the F keys.

If it is kind of an odd number, I wouldn't be opposed to cutting that vertical part out to even it up.

[dorkvader]

With a custom plate and PCB any layout is possible.

The "main block" is 15x wide as usual. The left column is 2x wide. They appear to be 0.5x apart but if you are cutting the part out you can just center your design in the open area and leave whatever space is left over on the edges. The rightmost navigation block is 1.5*3 instead of the usual 1*3. It has been suggested to cut out the vertical bar and put a tenkey on the right like the lightsaver. One good reason against it is that it takes so many extra keys you need two XT to make one XTant which doesn't preserve the remaining stock as well.

And, of course, the whole point of this exercise is as a stepping stone to fully custom model F made from modern components.

[berserkfan]

I'm going to chime in and sprout my usual spiel whenever possible. Hopefully eventually that will inspire people to do something.

Let's see someone build a matrix split layout model F!

[Hypersphere]

@wcass: It looks like the Xtant PCB is set up so that it would be possible to split the Backspace, Left Shift, and Right Shift. Is this so?

[wcass]

yes, backspace can be split.

The navigation block is 3 columns of 1.25 - so 3.75 key units wide.

[jacobolus]

I'm going to chime in and sprout my usual spiel whenever possible. Hopefully eventually that will inspire people to do something. Let's see someone build a matrix split layout model F!

I think “people” & “someone” = you, berserkfan. This isn’t an impossible challenge, all the necessary skills can be learned. If you want this to happen, you should do it.

[0100010]

If you got rid of the space between the main block and the left side 2x5 block; then moved the main block over leaving only a single 1x5 row, it would leave enough room on the right side for a 4x5 'numpad' plus a 1.25x5 column.  Would need a new PCB obviously.

[Melvang]

I'm going to chime in and sprout my usual spiel whenever possible. Hopefully eventually that will inspire people to do something. Let's see someone build a matrix split layout model F!

I think “people” & “someone” = you, berserkfan. This isn’t an impossible challenge, all the necessary skills can be learned. If you want this to happen, you should do it.

I would love to see this as well.

I need to take a closer look, but it looks like the default backspace on an  XT is 1.75 units, and not 2.

[dorkvader]

I need to take a closer look, but it looks like the default backspace on an  XT is 1.75 units, and not 2.

Just checked one of mine: backspace appears to be 1.75x though alt and capslock are both 2x

[Melvang]

I need to take a closer look, but it looks like the default backspace on an  XT is 1.75 units, and not 2.

Just checked one of mine: backspace appears to be 1.75x though alt and capslock are both 2x

So the primary block is 18.75 units + 2 for the left side 2x5 area + .25 for the vertical column making 21 total. 

Just wondering but are these plates going to support both XT and AT style barrels?

[0100010]

The XTant dxf as is only has the hole for XT barrels.  The index notch for AT barrels could be added though.

[Melvang]

Just wondering but does anyone have a link to keyboard layout editor for the physical layout?

Edit:  For some reason I went to go to KLE and build it myself, but one of the options when I started typing was what I was looking for.  Funny, I don't remember every building that layout locally, or clicking a link for it.  Either way, here it is.

http://tinyurl.com/pys9hwy

[fohat.digs]

So, help me out here.

Today I gathered up my pile of XTant gear and started looking at how to put it all together. I was planning to put the plates and PCB together in a dry run and drill a few holes here and there to use nuts and bolts to keep it all tight and nice. Then I would tidy up all the burrs and paint the new plate.

My impression was that most/some of the parts from the XT would be re-used but I can't see how to do it. I have most of 2 XTs so I can wreck some parts experimenting if I really have to.

Has anyone ever posted any photos or any type of semi-guide on how to assemble an internal assembly using the wcass PCB?

My single primary question is: does the wcass PCB attach to the original back plate, and, if so, how?

Thanks.

[Melvang]

So, help me out here.

Today I gathered up my pile of XTant gear and started looking at how to put it all together. I was planning to put the plates and PCB together in a dry run and drill a few holes here and there to use nuts and bolts to keep it all tight and nice. Then I would tidy up all the burrs and paint the new plate.

My impression was that most/some of the parts from the XT would be re-used but I can't see how to do it. I have most of 2 XTs so I can wreck some parts experimenting if I really have to.

Has anyone ever posted any photos or any type of semi-guide on how to assemble an internal assembly using the wcass PCB?

My single primary question is: does the wcass PCB attach to the original back plate, and, if so, how?

Thanks.

From what I am seeing with mine, you have to drill out the original rivets that held the original pcb, then drill holes that line up with the holes in the new pcb.

[fohat.digs]

From what I am seeing with mine, you have to drill out the original rivets that held the original pcb, then drill holes that line up with the holes in the new pcb.

OK, that's a start, and I was getting worried because one of those original rivets is practically under Enter.

But I am perplexed because I thought that alignment was crucially important. I see that the 2 side holes on the new front plate lines up with the side holes of the original back plate, and that the new PCB is the same size and shape as the old PCB, but am I just supposed to "mark and eyeball" the registration of the PCB between the metal plates?

Honestly, with my old eyeballs and primitive hand tools, I will do well to get 1mm accuracy in alignment. Presumably that is enough. F pivot plates are pretty large ....

[vivalarevolución]

Y'all need to check the DT thread.  Wcass went through the process in there.  I think everything you need to know is in there.  Check Page 7.

http://deskthority.net/workshop-f7/bringing-the-ibm-pc-xt-into-the-21st-century-t3047-180.html

[wcass]

I didn't take many pictures/video while I was building it because I didn't know if what I was doing would work.

Please do post your pictures and video!

[alh84001]

Currently not much to look at:


I went at a local shop and ordered a top plate today. I also decided to make a new bottom plate as well, since it was only additional $5 to $6. In the end top plate cost me around $25. I could have gotten it for less, but I was stupid and when the guy asked me how many holes it has, I said 84. He was content with that. But then I added that it also has 84 small holes as well, so all-together 170. I think they charge a bit for each cutout, so me and my big mouth cost me around $5  ) Lesson learned.

I'm not so confident in my CAD skills so I'll share the files when I see if everything fits together. They said that it will be done in a week, because they don't have 1.25mm plates in stock. After that, I still have to find someone to bend the plates. Small steps.

[fohat.digs]

Is anybody out there still interested in building one of these?

I have the parts needed to build it, including the 10 custom 1.25 caps for the right side from Unicomp.

This project has been on my list for quite a while, and I have finally resigned myself to the concept that I will probably not ever realistically get around to it.

There is the new PCB, plate, foam mat, xwhatsit, misc hardware, a whole XT (cut cable, but that won't matter) in acceptable condition, and an empty XT case in near-perfect condition.

International shipping would be a problem since it is heavy, but I will ship international if you accept the cost and the risk.

Private message me if you wish to discuss it.

[alh84001]

Well, I have additional set of plates already and I think extra case as well, so what I need is another PCB definitely and probably set of caps. However, if anyone else that still hasn't built it wants it, I think they should have precedence.

[0100010]

Doesn't the back of the new PCB have index marks on it, to align to the original backplate rivet locations?

Are the PCBs the same size?  Maybe grind off the heads of the old rivets, index the old PCB with them, place the new PCB over the top (be sure the tops of the rivets are smooth, or shorter then the old PCB so you don't scratch the new one) then use a wax marker to indicate the new PCB holes?  Or mark the edges of the old PCB to align the new PCB too?

Just throwing some ideas...

[fohat.digs]

Well, I have additional set of plates already and I think extra case as well, so what I need is another PCB definitely and probably set of caps. However, if anyone else that still hasn't built it wants it, I think they should have precedence.

I hope I can sell the lot in one go, but if I break it up I will keep you in mind.