Using stamps for numbers and lettering.

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Jan 4, 2019, 07:39 AM
drmico60

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Using stamps for numbers and lettering.

It is not easy to achieve a good spacing of numbers and letters when using stamps to mark metal.
A little trick that I have used several times is to first print out the text onto a paper label using a similar font and character size to the stamps.
The metal to be stamped is set up on a solid surface with a vertical straight edge to guide the stamps in a straight line. Stick the label onto the metal just in front of the straight edge and use the text to guide the position of stamp. The stamp can be pressed firmly into the label with hand pressure and this leave an indent in the label but not the metal so you can check the position. Once satisfied with the positioning then the stamp is repositioned in the label indent and hit firmly with a hammer to indent tne metal.

Attachment 27389

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Jan 4, 2019, 08:00 AM
rgsparber

This method works great. I found that Arial Unicode MS 14 is a close match to my Harbor Freight stamp set. I print out the text on my DYMO LabelWriter 450. Since all of the text to be stamped is visible, I can use a given stamp at every position that needs it. That way I don't have to pick up the same stamp twice. Does speed up the process a bit.

Now, if I could just be more consistent with my imprint depth...

Thanks drmico60,

Rick
Jan 4, 2019, 05:24 PM
bruce.desertrat

Duh! brilliant and simple idea! :thumbsup: I've been meaning to remake our dogs's name&phone ID tags, since their existing ones are kinda beat up, and I always seem to make them look more like a ransom note than anything else :-)
Jan 5, 2019, 03:30 AM
tonyfoale

Quote:

Originally Posted by rgsparber

Now, if I could just be more consistent with my imprint depth...
Rick

It would not be too difficult to make some form of stamp holder with a vertical extension to hold some form of weighty block at an appropriate height, on a slide. Add a trigger (for example) release and hey presto - even indents every time. A little experimentation prior to building would soon get the mass and height of the block determined.

Of course this will only work on surfaces that you can arrange to be horizontal. Although a bell crank could turn the force.
For non horizontal surfaces you could replace gravity with a solenoid or maybe a pneumatic cylinder into which you could rapidly dump a set volume of air at an appropriate starting pressure.
Jan 5, 2019, 06:23 AM
DIYer


Thanks drmico60! We've added your Stamping Guide to our Miscellaneous category,
as well as to your builder page: drmico60's Homemade Tools. Your receipt:

<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="http://www.homemadetools.net/homemade-stamping-guide-2"> <img src="/uploads/220075/homemade-stamping-guide-2.jpeg"/> </a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="http://www.homemadetools.net/homemade-stamping-guide-2">Stamping Guide</a> <span> by <a href="http://www.homemadetools.net/builder/drmico60">drmico60</a></span> </div> <div class="tags">tags: <a href='http://www.homemadetools.net/tag/guide'>guide</a>, <a href='http://www.homemadetools.net/tag/stamp'>stamp</a> </div> </div> </div> </div>
Jan 8, 2019, 01:37 PM
tonyfoale

Quote:

Originally Posted by rgsparber

This method works great. I found that Arial Unicode MS 14 is a close match to my Harbor Freight stamp set. I print out the text on my DYMO LabelWriter 450. Since all of the text to be stamped is visible, I can use a given stamp at every position that needs it. That way I don't have to pick up the same stamp twice. Does speed up the process a bit.

Now, if I could just be more consistent with my imprint depth...

Thanks drmico60,

Rick

Rick,

I was just idly browsing through a tools listing, not looking for anything in particular when this popped up
https://www.ebay.es/itm/38pc-AUTOMAT...sAAOSwzJ5XUrxZ
Something like that could be the answer to your even imprint problems, I guess that it works just like an automatic centre punch.
Jan 8, 2019, 02:01 PM
bruce.desertrat

I have one of those sets, it's not exceedingly powerful, and did not make decent impressions in steel; Also the letters are quite tiny. Yes, it's essentially a center punch with a stamp holder instead of pointy bit.

Maybe something like this Spring Center Punches & Nail Sets - Lee Valley Tools with a holder for the stamp instead of a punch on the business end.
Jan 9, 2019, 02:48 PM
drmico60

The problem with stamping uniformly is not solved by having a consistent pressure/impact. This is because each letter/number has a different total line length and therefore requires a different pressure. For example the length of the lines making up the letter H is nearly three times the length of the lines making up the letter I so to stamp an H needs nearly three times the pressure to get the same indent depth as stamping a letter I. Each letter is different so there require different pressure on the stamp.
Mike
Jan 9, 2019, 03:33 PM
tonyfoale

Quote:

Originally Posted by drmico60

The problem with stamping uniformly is not solved by having a consistent pressure/impact. This is because each letter/number has a different total line length and therefore requires a different pressure. For example the length of the lines making up the letter H is nearly three times the length of the lines making up the letter I so to stamp an H needs nearly three times the pressure to get the same indent depth as stamping a letter I. Each letter is different so there require different pressure on the stamp.
Mike

How come the flipping obvious is so often hidden in plain sight?
Mar 20, 2019, 04:07 PM
blkadder

I can't believe that I missed this when it was first posted. I have not had great luck with my stamping projects (usually home built firearms), and this would pretty much solve the issues that I was having. It would also be useful to make templates for etching information into metal. Thanks for posting this.
May 4, 2019, 08:08 AM
MrMetal

Good idea for spacing the letters. Getting uniform indents is a challenge. Uniform hammer blows is one thing but another aspect is that different letters require different blows. For example the letter "I" requires less force than the letter "M". Most of my stamping is in steel which requires a heavy strike. I use a heavy hammer to assure a good imprint with one strike. I hold the letter stamp in a pair of vise grips which prevents having the stamp fly off to a well hidden place in the event of an uneven strike. I've been thinking about a simple jig that would hold the stamps perfectly perpendicular to the work and also some spacers that would help get uniform spacing. After stamping one letter, replace the stamp with a short spacer of the same dimensions so that the next letter can be placed against it. Any ideas?
May 4, 2019, 09:04 AM
tonyfoale

Quote:

Originally Posted by MrMetal

I've been thinking about a simple jig that would hold the stamps perfectly perpendicular to the work and also some spacers that would help get uniform spacing. After stamping one letter, replace the stamp with a short spacer of the same dimensions so that the next letter can be placed against it. Any ideas?

http://www.homemadetools.net/forum/m...882#post105674
Jun 1, 2019, 01:55 PM
Thunderbelch

2 Attachment(s)

I made a simple jig that ensures even spacing. It is only really useful when you have a large enough flat surface to clamp it to. Even pressure was obtained by dropping a weight down a tube onto the punch. But as already mentioned, different characters need different striking pressures...

Tony - I much prefer the design you just posted!

Attachment 29902
Attachment 29903
Jun 6, 2019, 03:15 PM
DIYer


Thanks Thunderbelch! We've added your Stamping Tool to our Metalworking category,
as well as to your builder page: Thunderbelch's Homemade Tools. Your receipt:

<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="http://www.homemadetools.net/homemade-stamping-tool-4"> <img src="/uploads/224235/homemade-stamping-tool-4.jpeg"/> </a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="http://www.homemadetools.net/homemade-stamping-tool-4">Stamping Tool</a> <span> by <a href="http://www.homemadetools.net/builder/Thunderbelch">Thunderbelch</a></span> </div> <div class="tags">tags: <a href='http://www.homemadetools.net/tag/stamp'>stamp</a> </div> </div> </div> </div>
Jul 10, 2019, 11:53 AM
rjitreeman0909

Will take a little surface grinder or belt sander time but letter stamps could have left and right surfaces ground equally on letters such as an I to achieve the correct spacing. Would then require some rethinking of equally spaced guide holes if a secondary punch plate is part of the fixture design.
Aug 25, 2021, 12:19 AM
Saltfever

This is an old thread that just appeared in today's email. But it is an age old problem that every fabricator has been faced with. Most don't care if working for wages, but people in their own shop seem to take it personal! As indicated the problem is the unequal total line length that makes up all characters of the alphabet. I think the solution is probably something like Tony mentioned in his post #6 . However, quantifying the various weights would be the breakthrough. After that it is just a simple matter of sizing springs, fall distance, mass, or friction, of the application device you invent. So I was just playing and visually separated the alphabet into what I think might fall into about 6 weight groups. This is just a visual and some of you may think my focus is distorted or visually impaired! :D I did a serious search trying to find the total line length of each character but no joy. There is probably something in the art community, or those that design fonts for a living, but I found zero on the subject. A CAD system could do a much better job.

B E V L S T
M W X
I J
A H K N F Y Z
G P R
C D O Q U

There are 6 "weight" groups loosely based on the number of segments in the character or how I interpreted the amount of pressure was needed. Certainly you will think I messed up. LOL For instance the "I" and "J" are in the same group but depending on the dogleg of the "J" it might also have to stand alone. The idea would be test each group on a sample piece to set the correct pressure. I don't think each character in a group needs to be tested. Picking one character from each group to set that groups "pressure ratio" should get good results.
Aug 25, 2021, 02:13 AM
delalio

Hey Gents,

Very interesting thread. And something I've struggled with a bit in the past too.

Continuing on from the work of @Saltfever , @MrMetal , etc, I knocked up this.

It's based on the number of LEDs required for a given letter for a typical LCD digital display.

0.25 - .
1 -
2 - I
3 - J, L, T, Y,
4 - C, F, V, Z
5 - A, E, H, K, P, S, U, X
6 - D, G, M, O, R,
7 - B, Q, W
8

Let me know what you gents think. I'm going to have a play over the coming days and see how this works out...

Cheers,

Del
Aug 25, 2021, 03:09 AM
CanBeDone

Quote:

Originally Posted by tonyfoale

It would not be too difficult to make some form of stamp holder with a vertical extension to hold some form of weighty block at an appropriate height, on a slide. Add a trigger (for example) release and hey presto - even indents every time. A little experimentation prior to building would soon get the mass and height of the block determined.

I have tried that years ago - it produces multiple imprints because punch and hammer rebound. And I have also learned that I cannot suppress rebound even if I build the hammer as deadblow: my stamp, the item to be stamped, and the support upon which the item rests are all elastic, and will cause rebound. Once you look at the physics, you'll see why: dropping a hammer plus stamp of mass m a distance h stores energy
E=m.g.h
in it (g=9.81m/s is the acceleration of earth). When the stamp then penetrates a distance x, leaving its imprint behind, the (dynamic) force F it exerts is
F=Edx²/dt²
And in this formula all the problems with non-repeatable penetration depth are represented but not visible, since much of what goes into it is hidden: how the item deforms as the stamp starts to penetrate is a function of x, how much it is accelerated downwards due to the force applied to it, the mass and elastic properties of the support it rests on, you name it, all contribute to x, and as a result it muddies up the penetration depth x to make it as good as unpredictable. Since the stamp's downward moving velocity v is
v=dx/dt
it follows that, for repeatable penetration depth, the first derivative of x, the velocity with which the stamp moves downward must be close to zero, and thus the force, dependent upon the second derivative of x with respect to time t, exerted by the stamp on the item must be static in nature, not dynamic. And static forces require a press, not a hammer blow.
How potent a press? I have progressed so far that I can say for a 4mm number stamp I need a force in the vicinity of 5 ton for a decent impression in mild steel, i.e. an arbor press is ruled out as not powerful enough. The next question I need to decide is whether I want to measure and control the force acting on the stamp, using a strain gauge, or do I want to measure and control its travel into the item using a DTI? On that I am currently undecided, what is more robust? and what is more repeatable, to a measuring error of, say, 20 micrometer? After all, my eyes are quite capable of perceiving such a step, and that is the measure I need to apply.
Aug 26, 2021, 02:42 AM
Saltfever

Interesting and thanks for clarifying the rebound issue. Obviously, the rebound energy is dictated by the characteristics of the substrate. Stamping lead vs. hardened steel yields different rebound force. It could be by putting friction into the equation you can react the rebound energy. I have often just simply held the stamp between two fingers to lesson rebound. Applying friction may eliminate the need to apply differential force. Applying equal force, but adding variable friction may accomplish two things. It could overcome the rebound energy and also vary the force applied to individual letters. There are many creative ways to apply friction to a stamp. An example could be a pad pressing against the stamp with the friction adjusted by a bolt changing the length of a spring. To add some precision the spring could be calibrated and the bolt pitch would be selected for the appropriate change in length per revolution.