Centroid Community CNC Support Forum

Lots of users in German forums have problems parting steel with small hobby lathes, usually because they are cutting to slow....

... this is how I do it



Uwe

Thanks for the nice video Uwe, Quick question. I have only used my small lathe a handful of times. I watched another similar video using a carbide parting blade on a small lathe. I purchased the tooling shown below for my Aloris AXA tool post.

I noticed that you used a pecking approach when you were parting. The other video said when using carbide, don't stop, carbide does not like interrupted cuts. Once you start the cut, just keep going until you are done. I have not used this tool yet, but was curious what your thoughts are on pecking vs. continuous cutting?

Thanks... Richard

Pecking helps to evacuate the chips, no problem with carbide tools. Milling or turning hex profiles is interrupted cutting...

Pecking is only starting a new cut like on any other cut the tool starts turning.

Uwe

If you parting blade is cutting correctly, your chips will be nice "fiddle head" curls that won't pack in the cut. Most beginners make the mistake of not aligning the parting blade. You really should run an indicator down the blade.

Without pecking the first material would produce one very long curled chip per cut.

I hate to clean up those long curls

Uwe

Thanks. I haven't had a chance to try this tool yet but plan in giving a try in the next week or so. It does not look anywhere as rigid as the PWT, but the lathe came with an Aloris AXA tool post.

Have you had any luck parting aluminum with carbide tooling. The insert I have is a GTN-2. My lathe has a max rpm of 1000 in the low range and 2000 in the high range. I have never used the high range yet. Do you think it is necessary to use the high range for parting aluminum that has a 1 or 2 inch diameter?

Richard

For aluminium use sharp positive inserts and no TIN coating, since Alu sticks to it.

Cutting AW 7075 on my lathe:



Uwe

Thanks Uwe. Looks like you are running at 3000 rpm for aluminum. In high speed, the max rpm for my small lathe is 2000 rpm so I think I will try parting with the higher speed for smaller diameter parts.

Thanks for sharing the video... Richard

Do you think these would work well for aluminum?

https://www.ebay.com/itm/355588615166?i ... R6TbwpGZZA

Richard

I use MGGN200 for aluminum, because there are easy to find positive ones...

https://www.ebay.com/itm/166256238364?e ... R-TG7pmZZA

Uwe