Manual Drilling - Breaking Bits

[woodchucker]

Here's one hole drilled, tapped and with an M3x10 SHCS in place ( five such will hole the lathe rack in).View attachment 467614

can you give a shot from further away. It's kind of hard to see the whole picture of what's going on.

BTW, oil can work in cast iron, but it can also cause problems. Are you using compressed air to blow the hole out, or using a vac?

 

[SouthernChap]

Can I ask why you're drilling holes for a rack?

The reason I ask is that the rack on my 7x14 has a fair to middling bend on one end of it. Now, it looks like the holes drilled in the side of the bed are an attempt to ensure the rack at least sits straight once it's on there (or maybe there was just a happy confluence between sloppy drilling work and the shape of the rack! ).

Just interested why you're doing it really

 

[MaverickNH]

can you give a shot from further away. It's kind of hard to see the whole picture of what's going on.

BTW, oil can work in cast iron, but it can also cause problems. Are you using compressed air to blow the hole out, or using a vac?

I’m just running a pipe cleaner through the holes to clean them out - pretty low tech!

Can I ask why you're drilling holes for a rack?

The reason I ask is that the rack on my 7x14 has a fair to middling bend on one end of it. Now, it looks like the holes drilled in the side of the bed are an attempt to ensure the rack at least sits straight once it's on there (or maybe there was just a happy confluence between sloppy drilling work and the shape of the rack! ).

Just interested why you're doing it really

I’m upgrading my lathe from a 7x12 to a 7x16 bed and the LMS kit (bed, rack, lead screw) requires drilling holes to mount the rack and a few other select parts. I’ll also be mounting a DRO when it arrives next week. It will be a mini-marvel lathe soon!

I’ve no room for a bigger one and we have a huge South Bend at my local Makerspace for big jobs.

 

[Sticks]

Hand drill and, well, any metal requires muscle control.

A lot of people don't realize that the force the are putting is not in line with the hole that is being drilled. They all start well, then when you start to apply pressure, you are inadvertently pushing at an angle to the hole...snap.

Gotta think about it and visualize your muscle movements to go in a straight line with the intended hole.

 

[automan]

back it up with a sacrificial piece of aluminum.

cliff

 

[markba633csi]

Clamping a piece of wood on the backside when possible is good for preventing break-thru problems
You drill into the wood instead of the open air and it makes for a more controlled exit
Cliff beat me to it above ^

 

[MaverickNH]

back it up with a sacrificial piece of aluminum.

cliff

Clamping a piece of wood on the backside when possible is good for preventing break-thru problems
You drill into the wood instead of the open air and it makes for a more controlled exit
Cliff beat me to it above ^

I’ll try that, thanks!

 

[strantor]

A 2.5mm drill is just shy of 1/16" inch which is as small as most people go. They are susceptible to bending and breaking, especially when drilling metal with a hand drill. ... Hand drills, especially the battery operated kind, are lacking in rpm which makes it difficult for drilling with small drills. The drill will tend to take a bigger chip which is more likely to cause a jam and breakage. One has to go easy and let the drill do its cutting-at its own pace.

Yep.
Also they make little micro drill chucks you can put on a dremel that allows you to drill with those tiny bits at something closer to the proper speed.

Edit:
Dremel 4486 Keyless Chuck, ideal for 1/32” (0.8mm) to 1/8” (3.2mm) Shank Rotary Tool Accessories , Silver https://a.co/d/9H7rsVZ

 

[SouthernChap]

I’m upgrading my lathe from a 7x12 to a 7x16 bed and the LMS kit (bed, rack, lead screw) requires drilling holes to mount the rack and a few other select parts. I’ll also be mounting a DRO when it arrives next week. It will be a mini-marvel lathe soon!

I’ve no room for a bigger one and we have a huge South Bend at my local Makerspace for big jobs.

Ah gotcha. That extra space will be nice

Turns out there's still something amiss with the rack and pinion engagement on mine. Ordered a new rack just in case shimming the apron doesn't help; going to have my bed on the drill press myself, I expect...

...kinda wishing I'd gone down the tried and tested route of finding a decent Myford or Colchester.

 

[toprecyler]

One other thing that might help is to move your body keep your arms as close to your body as possible. I find thus helps keep my arms as still as possible. Especially if I can rest most of my arms to my body. With those small drill bits, need to keep as steady as possible.

I like using a white out pen correction marker to mark drill bits and other things. The white helps my eyes see the mark better.


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