DM 4400 tooling

I have a dyna 4400 still happily working under SKIP control. My tool holding is via ER collets. Largest size I have is ER 32 (20 mm capacity). I have a lot of 1 inch shank HSS cutters and even a tool and cutter grinder to keep them sharp and could easily buy a BT30 ER 40 to suit the mill and these larger tools. However, I have some concerns that this larger tooling with its longer collet chuck hangout might be a bit much for the BT 30. Has anyone out there experience with this or any thoughts..... Martin

Hi Martin!

Yes, the bigger tools cause massive amounts of fretting and even pull out if you take a big enough bite.
There is definitely a problem with the amount of clamping force available within the DM4400 spindle.
These machines are old and most of the Belleville washers have lost their spring.
Just replacing the washers with news ones does not cure this problem.
As far as I can tell it's the one of the only fundamental flaws in the DM4400.

I can only recommend that you use no bigger than a 1/2" (12mm) cutter and take multiple cuts.
I've been using 1/2" mills for years but I've just recently found that the 3/8" end mills work even better.
You can go full width and 1D with them at 48ipm no problem. Cutting aluminum that is....

I only use ER40 collet chucks to hold slitting saw arbors.

I hope this helps...

Timothy

Timothy, Thank you for your reply and very nice to hear from you again – I hope your Canadian winter is not to cold - our summer is a bit strange lots of cold (20 deg C ) wet days a few in the high thirties but none yet in the 40s.
You have confirmed what I was thinking. My situation is that through ill health I have had to give away a lot of my casting stuff amongst which will be my old Cincinnati #2 vertical mill. (The beast! I will miss her.) I have 50 or so 1 inch shank cutters for it and a tool and cutter grinder to keep them sharp (if only I knew how to use it properly????) All of these cutters are well over ½ inch diameter and many up to 4 inches long. My thought was to keep at least some of them and use on my Dyna. Of course, the Cincinnati has an ISO 50 taper and is built like an old dreadnought battle ship - at 500 rpm nothing but nothing can stop it - it can well handle such cutters.
I agree with you about the tool holding flaw of the Dyna. I have replaced the washers with new ones but don’t think it improved things much. I tried other arrangements of the washers. (I forget exactly but it was either a 3 *3 or a 4*4 arrangement that I tried) this would have increased holding power quite significantly but the pressing motor just blew the fuse and I was not going to get involved in upgrading all of that stuff. My thought with the large cutter in the BT40 was to use them mainly for wood and maybe for aluminium - what do you think of the chances if their use was restricted thus?
Regards Martin