1" spade drill on a 16" ?

I am putting a 3 hp. on my 16" but I am still skeptical about it pushing a 1" spade bit. I have never used one before. What are your experiences on using them on old machines, if not 1", what would be the largest I could use? Any advice on a coolant pump the won't cost as much as my 40's lathe would be helpful also.

Needing a little more info, what make and model is your 16"? is it a belt drive or gear head? What material are you drilling? I push a 2-1/4" series II spade in my 1939 16" monarch through a torch cut blank of 3" A514 a couple times a week, every week for a repeat offending job, wouldn't do it but money talks! I use a Little Giant coolant pump purchased on eBay for $100 +/-, a snap-lock concoction and simple ball valve to get the coolant to the point of contact. Push speeds and feeds just enough to keep the chips grey to a hint of straw color and my spade inserts make about 30" before they need a regrind... TIN coating on the spade inserts is a plus, my regrinds remove the coating and reduce the inserts efficiency but it pays. My Monarch only has a 5hp, but I have pushed a 3" spade through A36 and 1018 with no issues.

leod said:

I am putting a 3 hp. on my 16" but I am still skeptical about it pushing a 1" spade bit. I have never used one before. What are your experiences on using them on old machines, if not 1", what would be the largest I could use? Any advice on a coolant pump the won't cost as much as my 40's lathe would be helpful also.

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depends on metal alloy being drilled. normally if you remove a cubic inch of metal a minute and metal is 1018 steel it will take no more than 0.8hp. at a slow feed rate you will use less hp. you might have a problem drilling faster than 3.0 inch per minute feed

i'd run a `1" drill in back gear , soft steel. pilot drilled to 1/2" . should be around 120- rpm.



my 16" kicks ass . some don't .

It's got the single tumbler gear box, so it is an earlier SB, belt drive. Pilot hole? really? some say do, others say don't. Sounds like it will do it fine once I get the old gutless 1 1/2 p motor swapped out. It will be 1018 steel. I am glad I can just use a pond pump, I got a bunch in my animal supply boxes. I wasn't looking forward to a high pressure pump on an old south bend with everything wide open. I will probably make a plexiglass shield for around the chuck though so I am not flinging it to the ceiling.Sucks I can only look forward to 30 " of use before regrind,you sending them off, or doing it yourself?

The only time I pilot drill is if I am on a BP, I don't wanna swing off the quill handle trying to pull a 1" drill thru inches of material.

Sometimes on a lathe that has center line issues I will run a pilot thru just undersize so I can ream it out with the finish size.

You never want to use a spade in a piloted hole...well, you can but you run a big risk of making a damn mess of your spade and part.
Twist drills can manage being stepped out because the flutes act as a guide to help keep it on center.
The spade bar having no flutes and lots of clearance between the spade bar and wall of part will want to jump around and cause you problems.
You can spade out an existing hole, but you most likely will not want to do it again.

A nice sharp spade will not be an issue, keep her around 200 RPM if its mild steel and stuff the spade to her. If a small J Head BP can pull a 1" twist
in 4140 with no problem...your 16" lathe will drill it like butter.

How deep you plan on drilling means a lot concerning your coolant pump.
Twist drills have flutes to make the chips move out the hole.
The spade bar needs enough pressure from the coolant to not only cool the insert but to flood the chips out the hole as well.

At 1" if your just drilling a couple inches and you aren't spinning to fast it will not be an issue just as long as the tip is getting some fluid.
If your drilling several inches it would be really nice to have the pressure to force the chips out so they don't load up in the hole.
You can of course just keep going in and out to clear the hole due to lack of pressure but that's a pain in the ass.

When you setup and ready to spade..
Do not be afraid to get after it with the hand wheel on your tailstock.
In a good setup, you should be able to feed that spade in fast enough to break a chip.

Small curved chips should just flow right out with the coolant. If a long stringy chip comes out, you most likely are not feeding fast enough..CRANK FASTER.
Try to stay in the cut and steady feed from start to finish, the spade will last longer if it isn't being shoved in and out and in and out through chips up in the hole.

leod said:

It's got the single tumbler gear box, so it is an earlier SB, belt drive. Pilot hole? really? some say do, others say don't. Sounds like it will do it fine once I get the old gutless 1 1/2 p motor swapped out. It will be 1018 steel. I am glad I can just use a pond pump, I got a bunch in my animal supply boxes. I wasn't looking forward to a high pressure pump on an old south bend with everything wide open. I will probably make a plexiglass shield for around the chuck though so I am not flinging it to the ceiling.Sucks I can only look forward to 30 " of use before regrind,you sending them off, or doing it yourself?

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The material I'm drilling in shortens the life, in 1018 with coolant you'll probably see 100 + inches. I made a fixture to grind them on my T&C grinder, I started my business 26 yrs. ago as a tool grinder, it's painful to go back to my roots so I'll buy surplus inserts on eBay and when I reach a level of dulls that justifies the setup - I spend a few hours grinding... I agree with IronReb, a pilot hole for a spade will cause nothing but grief, unless the pilot is the dimension of the chisel point... not worth the effort. Try it without a pilot, and as IR stated also - put some effort in to pushing it.

I want to drill 8 to 10" blind holes and will need to use the carriage. I have very messed up hands from a motorcycle wreck years ago and the right wrist is fused with a titanium brace.I think amec calls for something like 65 psi. That would make a serious mess and take a hell of a pump. water supply pumps for rv's will do that, but I don't know for how long with those kind of conditions. I may have to use a large tank charged with air.

Leod

Drilling with the carriage that deep can be done so you can use the carriage feed but your setup must be top shelf
or you risk something moving and wrecking your part or spade, or in worse case scenario, snapping your carriage casting.

If your planning to be making a lot of these I would strongly suggest an alternative, like rigging a linkage from the carriage to the tailstock
and pulling the tailstock with the strongest part of the carriage so as to take the pressure of the side of the slide.

If your budget and room allows, you could find one of these pretty damn cheap https://images.search.yahoo.com/sea...e.info/photos/121386099401_1.jpg&action=click

A turret lathe will spade all day everyday very fast and very easy. These machines were made like candy for the war effort so there should be still tons of these things around to be picked up on the cheap.

F that cranking the tail stock, put that spade on your tool post and feed it under power. A few people will post not to do it because it will wreck the lathe. BS, I have been drilling with the carriage on my SB since the 70's and it is fine.

I forgot about the pushing or pulling the tailstock with the carriage bit. I will have to try that. when using the carriage though, I have learned that the tool post pivoting just slightly causes bad things real fast. I plan to make a tool holder that holds the boring bar in line with the tool post bolt, as apposed to off the side of it.I have seen a few turret lathes for sale around here for a reasonable price, they don't seem to be in near as much demand as a regular engine lathe, not sure I could get the depth I want from the ones I have seen though.

leod said:

I forgot about the pushing or pulling the tailstock with the carriage bit. I will have to try that. when using the carriage though, I have learned that the tool post pivoting just slightly causes bad things real fast. I plan to make a tool holder that holds the boring bar in line with the tool post bolt, as apposed to off the side of it.I have seen a few turret lathes for sale around here for a reasonable price, they don't seem to be in near as much demand as a regular engine lathe, not sure I could get the depth I want from the ones I have seen though.

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I think if I were considering drilling big holes this way, I'd look at removing the compound and attaching the spade bit holder directly to the cross slide. I have no experience drilling this way, but sounds reasonable if it's mounted rigidly.