Columbiar Report post Posted March 17, 2017 It looks like pricking chisel size nomenclature is different from that of a overstitch wheel. Is there a rule of thumb for equivalency? For example, what size chisel would be similar to a number six overstitch wheel? Quote Share this post Link to post Share on other sites
Mattsbagger Report post Posted March 21, 2017 4mm roughly 8 dpi. 5mm roughly 6spi.3mm roughly 10 dpi. Quote Share this post Link to post Share on other sites
Bolt Vanderhuge Report post Posted March 21, 2017 But even that changes from chisel/iron manufacture to manufacturer. I have irons from different places that are both labeled as 4mm yet they have different tpi from what I assume is how they are measured to get that number. Quote Share this post Link to post Share on other sites
billybopp Report post Posted March 21, 2017 For irons that are marked with a number, sometimes that number will tell you the number of stitches per inch and others will tell you teeth per inch. So, for example, one maker's 6 is 6SPI, and another maker's 7(TPI) gives you 6SPI. With the cheapie Chinese ones, they are usually marked in mm, but they are cheap so that might not be totally accurate. To me at least, that's not all that important as long as they are ballpark correct and consistent. I don't really care if the stitches are 6.5SPI or 7SPI. It's much more important that they are evenly spaced, angled, and thickness, and consistent across irons in the line (eg 10 tooth, 6 tooth, 4 tooth and 2 tooth). Bill Quote Share this post Link to post Share on other sites
slipangle Report post Posted March 26, 2017 (edited) Interesting question. I just purchased some Crimson Hides chisels. 3.85 mm spacing between teeth. Only to find that none of my vintage overstitch wheels , 6, 7 or 8 marks per inch, etc., are exactly the same. 7 is close, but not quite. Metric vs. inch is the problem. Edited March 26, 2017 by slipangle Quote Share this post Link to post Share on other sites
William Bloke Report post Posted March 27, 2017 On 21/03/2017 at 1:41 AM, Mattsbagger said: 4mm roughly 8 dpi. 5mm roughly 6spi.3mm roughly 10 dpi. No it's not. 3mm is just under 8 1/2 to the inch, 4mm is about 6 1/3, and 5mm is close enough to 5 to the Inch that it makes no difference. Quote Share this post Link to post Share on other sites
Mattsbagger Report post Posted March 27, 2017 Well thats what what mine measure to. As i mesured as i posted and said roughly. Quote Share this post Link to post Share on other sites
Brianm77 Report post Posted March 27, 2017 Different manufactures measure differently. I have a couple craft sha chisels. 1.5 mm is about 9spi Quote Share this post Link to post Share on other sites
