**How do we optimize each product page for 1 keyword phrase.? **
You need to be very careful when attempting to optimize pages for such similar keywords. "manual coldsaws", "manual cold saws" and "affordable manual cold saws" would likely best be presented as a single page optimized for "manual cold saws".
I tried a search for "manual coldsaws" and Google showed results for "manual cold sores" automatically with the option to click a link to search for "manual coldsaws". It does not seem worthwhile to specifically create a page for this uncommon misspelling.
I recognize you are trying to target all the various keyword combinations a user may enter as a search query. My recommendation would be to make a single, high quality page which focuses the target keyword but may include content on slight variations as you feel necessary. The content for a single, high quality web page costs hundreds of dollars to create. A single infographic may cost thousands of dollars. Content is expensive! I would suggest not wasting it on variations which do not offer a lot of value to users.
If you use this idea, you can use anchors and headers to divide the page into sections. Wikipedia does this very well. The main page can focus "manual cold saws" but you can have a section on "best quality" and another section on "most affordable".
It sounds like the sole reason you are considering this method is to adjust for search engines. This is where I fall back to the saying you have heard many times...design your site for people, not search engines.
PS. I checked the traffic for "manual cold saws" and was unable to see any organic traffic numbers for that query. I would suggest it is not a keyword worth spending any extra time on for page variations.