Hq400 drawbar question

[Carbon_Canyon]

I picked up a late 80s HQ400 3 in 1 and it only came with a couple of tools. I've been looking at Morse taper 3 tooling for the mill portion, and my options appear to be tang style and drawbar style.

There is a hole down the center of the milling spindle, but it's pretty small. M8 and 5/16s bolts fit, but the tooling ads I see show 3/8s and M12 as the common drawbar thread for MT3.

Am I going to need to make a special drawbar that will have to install from the bottom up instead of top down? Is a 5/16s drawbar strong enough for an MT3 tool on a small machine like this?

 

[wa5cab]

5/16" should be OK although as you said, you will have to make the drawbar such that you can install it from the bottom. Use something stronger than 1018/A36, though. And don't even think of using a tang type end mill holder. I don't know why anyone was ever dumb enough to make them. Sooner or later they will come loose and ruin what you are working on. Even in a lathe with it horizontal. Speaking from actual experience.

 

[Carbon_Canyon]

Yeah, read up enough about people using drill presses as mills to get that tangs are bad. The mill spindle does have provisions for a tang style holder with the window in the side of the spindle for a release tool. Just having a hard time finding anything online that is MT3 taper with a 5/16 or m8 drawbar thread. The tool did come with a single MT3 to JT3 chuck adapter, and it is threaded M8, so they do exist, just maybe not mass market. My other thought was to try and drill out the spindle to 3/8's, but that is pushing my abilities and current tooling. Looks like I need to go find some Grade-8 allthread. Thanks.

 

[wa5cab]

The tang-type male taper is commonly found on drill bits and is OK there.