Drilling With A Mini Lathe

[Tool Chatter]

I have a very newbie question about drilling on a mini lathe. I have a Wen 3455, that I think is the same thing as a SEIG 7 x 12 mini lathe. For my first use and project, I need to make some axle spacers for a rear wheel of a motorcycle. The bore of the axle spacers will need to be 25.00mm ID. So I'm wondering if I'm better to buy a reduced shank 25.00mm drill bit, or a 25.00mm drill bit with a morse taper to fit the tail stock? I'm new to all of this, so I'm assuming that a morse taper is a universal size? I guess my thoughts are the drill bit would be straighter mounted in the tail stock, than if mounted in a chuck on the tail stock.

The material I'll drill will be 6061 aluminum round bar. Am I going in the right direction using a drill bit with the morse taper?

Thanks for any help, and I look forward to learning here.

 

[benmychree]

In any case it would be better to drill the hole undersize and bore to the finished diameter. Drilling with MT drills in the tailstock risks spinning the shank of the drill in the tailstock taper, causing galling/damage to the taper, resulting in a poor fit for the center and inaccuracies when turning diameters using the tailstock center. This is generic info/comment, it applies to all lathes without a tang slot in the tailstock quill, which very few lathes possess.

 

[MSD0]

I would use a boring bar. You will have to drill a clearance hole first.

 

[mikey]

I would use a boring bar. You will have to drill a clearance hole first.

This. 25 mm is slightly bigger than 1" ID - biig hole to drill. You are far better off boring it, and in aluminum it will be fast.

 

[Tool Chatter]

That makes very good sense, to not risk damaging the tailstock, that hadn't occurred to me at all. As far as drilling a smaller initial hole through the aluminum, what would be a recommended percent of the finished size? Something like 80% to 90% of the finished 25.00mm?

 

[Tool Chatter]

I would use a boring bar. You will have to drill a clearance hole first.

What are you refering to by borring bar? Please overlook my lack of machine shop knowledge.

 

[royesses]

I use a drill bit in an mt2 drill chuck. The size starter hole is determined by the required diameter for clearance of the boring bar. My smallest bar requires a 5/16" bore but I would drill it to within 20 to 25 thousandths of 1/2" or as close to that as possible. Then bore to finish. Also I let the part cool down to room temperature before measuring for the final pass if I need the bore to be close tolerance. Just the way I do it on my mini lathe.
LMS boring bar set.

A.R. Warner HSS boring bar from LMS


Roy

 

[markba633csi]

A boring bar is a slender rod-like tool with a cutting bit at the end that mounts in your cross slide. You can spend tons of money on them. You can also make them for little money and it's even possible to use the edge of a drill bit as a boring tool, I've done it in a pinch.
Mark

 

[Tool Chatter]

Ok, I see now, I looked at a boring bar just now at the Little Machine Shop. That's a really flexible setup, 0.750" to 3.000" range too. And I will keep in mind to let the axle spacer adjust to room tempuratture before the final pass.

Thanks guys, really helpful info.

 

[turnitupper]

25 mm is slightly bigger than 1"

Smaller,Mike, if he drills 1" and tries to bore it to 25mm it wont work. Perhaps he could use a boring bar that adds metal. I have had use for one many times but the machinery vendors always seem to be out of stock. Must be a very popular tool.
John.