The only reason it may matter is it limits collet choices when you want more later, and also the diameter stock that can pass thru the collet.

I have also seen 10mm but that seems less popular, along with 6mm. PO Box, Albania, Algeria, Andorra, Angola, Anguilla, Argentina, Belarus, Benin, Bosnia and Herzegovina, Botswana, Brazil, British Virgin Islands, Burkina Faso, Burundi, Cameroon, Cape Verde Islands, Central African Republic, Chad, Comoros, Congo, Democratic Republic of the, Congo, Republic of the, Côte d'Ivoire (Ivory Coast), Djibouti, Ecuador, Equatorial Guinea, Eritrea, Ethiopia, Falkland Islands (Islas Malvinas), Gabon Republic, Gambia, Ghana, Guinea, Guinea-Bissau, Guyana, Haiti, Kenya, Lesotho, Liberia, Libya, Macedonia, Madagascar, Malawi, Mali, Mauritania, Mauritius, Mayotte, Moldova, Montenegro, Morocco, Mozambique, Namibia, Netherlands Antilles, Niger, Nigeria, Peru, Puerto Rico, Russian Federation, Rwanda, Saint Helena, Saint Vincent and the Grenadines, San Marino, Senegal, Serbia, Seychelles, Sierra Leone, Somalia, Suriname, Svalbard and Jan Mayen, Swaziland, Tanzania, Togo, Tunisia, Turkmenistan, Uganda, Ukraine, Vatican City State, Venezuela, Virgin Islands (U.S.8mm seems to be the most popular collet size for these lathes. Antigua and Barbuda, Aruba, Australia, Austria, Bahamas, Bahrain, Bangladesh, Barbados, Belgium, Belize, Bermuda, Bolivia, Brunei Darussalam, Bulgaria, Cambodia, Canada, Cayman Islands, Chile, China, Colombia, Costa Rica, Croatia, Republic of, Cyprus, Czech Republic, Denmark, Dominica, Dominican Republic, Egypt, El Salvador, Estonia, Finland, France, French Guiana, Germany, Gibraltar, Greece, Grenada, Guadeloupe, Guatemala, Guernsey, Honduras, Hong Kong, Hungary, Iceland, Indonesia, Ireland, Israel, Italy, Jamaica, Japan, Jersey, Jordan, Korea, South, Kuwait, Latvia, Liechtenstein, Lithuania, Luxembourg, Macau, Malaysia, Maldives, Malta, Martinique, Mexico, Monaco, Montserrat, Netherlands, New Zealand, Nicaragua, Norway, Oman, Panama, Paraguay, Philippines, Poland, Portugal, Qatar, Reunion, Romania, Saint Kitts-Nevis, Saint Lucia, Saudi Arabia, Singapore, Slovakia, Slovenia, South Africa, Spain, Sri Lanka, Sweden, Switzerland, Taiwan, Trinidad and Tobago, Turks and Caicos Islands, United Arab Emirates, United Kingdom, United States

Hobbymat universal md65 lathe manual