Insertable Spade Drill in a Bridgeport?

[schmidty13]

I have a job that has become a fairly regular repeat job so I am looking for process improvements. It is drilling five 13/16" holes in 2" thick steel. The way I have been doing it is pilot hole first, then the 13/16 twist drill. I was considering investing in an insertable spade drill to reduce time and effort.

I've never used a spade drill in a manual machine, so I'm unsure if the machine has enough HP and if I can give it the feed pressure it would want. Being it's only 13/16", I would think so, but it's a big investment to make on a guess. I've just started diving into the catalog recomendations to figure it out, but was hoping I could take a short cut...anybody ever used an insertable spade on a manual mill?

 

[benmychree]

I doubt very much that a BP type machine could manage a spade drill, and BTW, they do not like pilot holes. I have done a lot of drilling holes with them in my younger days.

 

[Watchwatch]

Have you tried an annular cutter? It will remove the need for a pilot hole and be easier to drill.


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[schmidty13]

I doubt very much that a BP type machine could manage a spade drill, and BTW, they do not like pilot holes. I have done a lot of drilling holes with them in my younger days.

The lack of pilot hole is why I was thinking spade...remove one operation.

 

[schmidty13]

Have you tried an annular cutter? It will remove the need for a pilot hole and be easier to drill.

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I have not. I found this HM post about them. Only read page one so far, but they may have talked me into it. Will keep reading. Thanks for the suggestion!

 

[ljwillis]

The 2" depth of cut annular cutters can be expensive, but it's definitely the way to do this. I have a morse taper adapter to use them on the lathe, too, and I only wish I had done it sooner. Hours of time saved. The small contact area and large number of teeth will make quick work of these holes.

 

[Buffalo21]

The Beaty of the annular cutter, is the spring loaded arbor, that pushes the slug out, using a 3/4“ collet, will negate that feature, I use a R8 x annular cutter adapter.

 

[schmidty13]

The Beaty of the annular cutter, is the spring loaded arbor, that pushes the slug out, using a 3/4“ collet, will negate that feature, I use a R8 x annular cutter adapter.

I was wondering about this. I don't want to have to stop after every hole and tap out the slug...especially since these parts have 5 holes. I just started looking, but if I use a 2" cutter, I need a 2" holder?

Another question; I will be drilling in 2" thick material...does a 2" cutter truly have 2" cutting depth? Maybe a silly question, but I don't want any surprises.

 

[projectnut]

I doubt very much that a BP type machine could manage a spade drill, and BTW, they do not like pilot holes. I have done a lot of drilling holes with them in my younger days.

It's interesting that you don't think a Bridgeport could manage spade drills. I purchased a set a several years ago to use in my Bridgeport. So far I've only used the smaller ones, but haven't had any troubles. I must admit I believe the set I bought is a specialty set, possibly for use on a Brown & Sharpe screw machine. Some are left handed, and are ground for cutting brass.

My mill is 1 1/2 hp, but is running on a static converter, so the output is in the 1 HP range. When I do use them it's in low range, but so far they've done a good job.

Attached are a few photo's of the set. They're made by B&W Precision Products out of Detroit. They're in a fitted aluminum box that was apparently meant to be shipped through the US Mail back to the company when they needed sharpening.

 

[mmcmdl]

How about an insert drill such as Valenite or Carbaloy ?