They can be purchased from any Keencut dealer near you and if you aren’t sure who that might be you can use our website to find the nearest by visiting this page – https://www.keencut.com/find-a-dealer/
The most common issue with V-grooving over the ST250 length is actually down to user technique and is easily solved. We have a short video explaining this in more detail which can be found in our Steeltrak support page in the tips and tricks section – https://www.keencut.com/support-category/steeltrak/
Have a look at this video and see if this sorts the issue out for you. If not please get in touch again on [email protected] and I will be abel to offer further assistance
Your message says you ‘have started’ experiencing issues with v-grooving. Can I ask how long you have had the machine and if you were getting a consistent V-groove that has now changed or if you have never been able to get a consistent cut?