Need Steel Drilling Help

[UpSideDownClown]

The pieces look to be about 24” long. To make shipping easier, could you make a center piece with slots and 2 outer pieces with matching slots so you’d get your adjustability? Adjust to width needed and tighten 4 bolts to lock it into place. This would also allow the pieces to fit in a smaller box. The USPS medium flat rate box comes to mind. The rectangular box is around 12” on the long side. The boxes are free, they will even send you a bundle rather than going to the post office. Since it’s a flat rate box, you know what your shipping cost is so you come up with an all in price and offer “ free shipping”

They're 19" long, and I considered making the bar multiple pieces to allow for a smaller shipping box, but didn't take it past the concept stage.

 

[JeepYJ]

While you’re there buy a center punch as well.

And buy a can of this

12 Oz. Thread Cutting Lubricant

Amazing deals on this 12Oz Thread Cutting Lube at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

 

[mark-NJ]

delete

 

[alfadan]

Only thing I can recommend is to use a vise in a drill press and locate one of the holes, find a way to clamp a work-stop to the press or vise, and do all the same hole in each part. Then find your next hole and do all those in one setup.

 

[UpSideDownClown]

I suspect the cheapest way to get 20 of these is to have a service company like SendCutSend laser cut them. The cost of finished parts is likely comparable to your cost for the raw steel and they will be more accurate than you can do.

If you want to do it yourself, look at getting a decent used drill press off of Craigslist or Facebook Marketplace. You want a metal drill press, which runs at low rpm and high torque. Something from the 1950's or 1960's can be surprisingly good. Make sure you get a 120 volt drill press; many of the industrial ones are 240 volt or 240 volt 3-phase.

After people here at Garage Journal pointed me to them I've become a fan of Harry J. Epstein and their Norseman drill bits. Industrial drill bits available in single sizes at good prices. With a decent drill press you can drill a 3/8" or 7/16" hole directly without a starter hole.

Get a drill press vise and bolt it down. This will position your holes more accurately and will be much safer - the drill will want to bind when it breaks through the back and a large chunk of spinning steel can quickly make for a bad day. Don't ask me how I know...

Be careful, don't do anything stupid, and be proud when you have done it!

SendCutSend came back and said well since we don't offer welding, we won't bother to quote cutting the holes. This is exactly the kind of response I typically get, that forced me to go after cutting the holes myself. A member here has reached out to me to possibly help, and actually he might be able to cut adjustment slots instead of the small holes on the ends, which would be better. I had abandoned the idea of slots when I got silly quotes from shops. Fingers crossed on that.

 

[Jswain]

SendCutSend came back and said well since we don't offer welding, we won't bother to quote cutting the holes. This is exactly the kind of response I typically get, that forced me to go after cutting the holes myself. A member here has reached out to me to possibly help, and actually he might be able to cut adjustment slots instead of the small holes on the ends, which would be better. I had abandoned the idea of slots when I got silly quotes from shops. Fingers crossed on that.

What part of those bars pictured needs welding? I'm assuming you're doing any welding yourself as you only asked about drilling the holes?

 

[zendriver]

Pic of working prototype of the bars

USDC

So, that's it? You can get $150

Build a jig similar to this and use a decent drill press. Make a million of them and they will be drilled dead nuts every time.

Also, I'd run them through something like this. Corrosion resistance and better uniform appearance, especially at that price.

Parkerizing | DuraCoat

duracoatfirearmfinishes.com

Good luck.

 

[UpSideDownClown]

What part of those bars pictured needs welding? I'm assuming you're doing any welding yourself as you only asked about drilling the holes?

A 7/16 nut gets welded to one side of the big drilled hole. No, I don't weld. I asked here about drilling the holes, then I would go to my local guy for the welding at the same time I take him another project that gets welded. There was a recommendation to go to a high-end shop for the drilling, so I asked them to do the welding too. Of course, this messed things up.

 

[UpSideDownClown]

So, that's it? You can get $150

Build a jig similar to this and use a decent drill press. Make a million of them and they will be drilled dead nuts every time.

Also, I'd run them through something like this. Corrosion resistance and better uniform appearance, especially at that price.

Parkerizing | DuraCoat

duracoatfirearmfinishes.com

Good luck.

This is only one part of the 2-in-1 tool. There is a specialty 1/4" thick plate that required CNC capability, and I paid to have the prototype made. I had to shop around for that, as well as another plate that doesn't require machining. Then there are press-down pieces of allthread that need to be the right length, and have a nut welded to the end of them. All of that required validation on an actual transaxle, and to top it all off, I had to get the transaxle apart first, which normally requires, well, THIS TOOL (or an inferior equivalent). This isn't hack work here.

 

[Jswain]

A 7/16 nut gets welded to one side of the big drilled hole. No, I don't weld. I asked here about drilling the holes, then I would go to my local guy for the welding at the same time I take him another project that gets welded. There was a recommendation to go to a high-end shop for the drilling, so I asked them to do the welding too. Of course, this messed things up.

Could you maybe thread the plate with a tap instead of welding the nut? That's easy enough to do yourself.

Either way I think you'll be styling with a drill press to drill the holes, just need to figure the rest out to make it economical

 

[UpSideDownClown]

Could you maybe thread the plate with a tap instead of welding the nut? That's easy enough to do yourself.

Yes, tried that, spent money, didn't work out so good. Concluded that it wasn't worth it relative to just having the shop weld a nut on instead while he had my other project in there for welding. One lot charge.

 

[scooby074]

There are thousands of small CNC plasma tables out there in hobbiest hands now. Check with your local metal supply house and see if they know anyone. Chances are, they could also do your welding for you. Even look for somebody cutting out those metal house signs. Perfect for a cash side job

This just screams CNC to me. You could rip 20 sets of those out in an hour.

Or get the larger HF drill press and GOOD drill bits ($150) + a jig. Cheap drill bits are a false economy.

 

[zendriver]

This is only one part of the 2-in-1 tool. There is a specialty 1/4" thick plate that required CNC capability, and I paid to have the prototype made. I had to shop around for that, as well as another plate that doesn't require machining. Then there are press-down pieces of allthread that need to be the right length, and have a nut welded to the end of them. All of that required validation on an actual transaxle, and to top it all off, I had to get the transaxle apart first, which normally requires, well, THIS TOOL (or an inferior equivalent). This isn't hack work here.

You asked about drilling holes with a harbor freight drill press.

 

[UpSideDownClown]

You asked about drilling holes with a harbor freight drill press.

Yes, I did. It is time for me to leave now. Happy trails.

 

[JeepYJ]

Yes, tried that, spent money, didn't work out so good. Concluded that it wasn't worth it relative to just having the shop weld a nut on instead while he had my other project in there for welding. One lot charge.

To just weld a nut on a piece of steel a little 120v flux core welder would do that just fine. A couple practice runs and you can do it.

 

[UpSideDownClown]

Absolutely this. For the best accuracy in hole location, a center drill can be used before the first drill bit. With a bit of care, it's possible to hold pretty tight tolerances.

Circling back to this, so let me see if I understand; I would use one of these, 1 suggestion was to use a '#3', and then go right to my finished size using a high-quality regular bit? Why isn't there a regular shank on this type of bit? Do I still use a center punch first? Thanks.

 

[Firebrick43]

Circling back to this, so let me see if I understand; I would use one of these, 1 suggestion was to use a '#3', and then go right to my finished size using a high-quality regular bit? Why isn't there a regular shank on this type of bit? Do I still use a center punch first? Thanks.

Center punch still yes. I wouldn't go straight to 3/8 bits especially on smaller drill presses. Drill with 1/4" after the #3 center drill, then go to 3/8" or 7/16".

They are short so they don't deflect although they do have long reach ones if you look. Dual sided to get twice the life.

 

[mreisner]

What about using a metal punch? Sometimes can find them for pretty cheap, they are fast and accurate.

 

[mreisner]

Not a new one, but I have a couple I have found used in the $75.00 range.

 

[Firebrick43]

What about using a metal punch? Sometimes can find them for pretty cheap, they are fast and accurate.

That is going to require an iron worker for that thickness not a little hand powered job like a greenlee or roperwhitney

 

[Firebrick43]

Not a new one, but I have a couple I have found used in the $75.00 range.

a 7/16" hole in 3/8 metal is going to take at least 11 tons minimum. And ideally you to want to be operating on the minimum end. That is twice of the press you show

 

[UpSideDownClown]

That is going to require an iron worker for that thickness not a little hand powered job like a greenlee or roperwhitn

a 7/16" hole in 3/8 metal is going to take at least 11 tons minimum. And ideally you to want to be operating on the minimum end. That is twice of the press you show

I'm lost. I'm going to stick to the center drill idea for now. Thank you.

USDC

 

[Firebrick43]

I'm lost. I'm going to stick to the center drill idea for now. Thank you.

USDC

You should stick to drilling for now in the prototype/preproduction phase.

Just so you are aware of what is being talked about there are presses that can punch metal very quickly. Many of the punches have small *** on them that engages a center punch mark that you can feel.

It would be something to think about if you end up producing a lot of them. You could lay out the holes and punch mark them and a shop with a punch press could know out maybe several hundred holes in an hour.

 

[CapriMikeC]

The Harbor Freight drill press will work for making your parts. https://www.harborfreight.com/power...speed-bench-drill-press-with-light-58780.html

As mentioned, make up a simple jig to locate the work pieces for repeatability and rigidity. The jig can be just some pieces of wood held to the drill press table using c-clamps or bolts through the table slots. Like a fence on a table saw or chop saw.

What makes the drill press work so much better than a hand drill is the ability to apply even force in a straight line to the cutting tool. Hand drills are difficult to keep perpendicular and hard to maintain even force on the work piece.

For drill choices, high speed steel (HSS) with 118 degree point is the most common at local hardware stores and least expensive. For your A36 steel, these will work fine. Cobalt drills are still HSS but have higher amounts of cobalt (duh) allowing them to operate at higher speed (friction and heat) without losing their cutting edge. Additionally, the cobalt drills will typically have 135 degree points which will cut easier and remain sharp longer. Don't worry about coatings.

So for a 118 degree HSS drill, you'll want about 600 rpm and to apply enough pressure for the drill to make chips not specks. A good reference to what the chips should look like is this Project Farm video:

If you were local, I'd be happy to help.

 

[mreisner]

You need to buy stuff like this from an authorized seller. Check on Makita's website for a list.

The same is true for things like ball bearings; if you buy an SKF bearing on Ebay, there's a good chance it's counterfeit; if you buy one at your local industrial supply store, like Motion Industries, it's going to be real. SKF has an entire division that does nothing but identify counterfeits.

That is going to require an iron worker for that thickness not a little hand powered job like a greenlee or roperwhitney

My mistake, thought it was 3/16 not 3/8!

 

[All]

Before becoming disgruntled with me for resurrecting a 5 month old thread, please remember that whenever one attempts to start a new thread on GJ, the forum software suggests and requests that existing threads be reviewed for the answer first, and then presents related threads for that review session.

The GJ software works quite well in this regard, and presented THIS thread as on topic with my question, which is as follows:

How many steps should I use to drill 1/2" diameter holes through 3/8" thick A36 mild steel?

I'm using HSS twist drills (Silver & Deming type) with a 20" drill press at 150 RPM (slowest belt setting) with the bar clamped in a drill press vise that is bolted to an X/Y table.

I've center punched the holes where I want them, and then have started off with an 11/64" diameter pilot bit, which is a hair under 3/16". The reason for the 11/64" pilot is simply because that was the only small diameter bit that I had that was long enough to reach the work at the table height that I have, which I don't want to change.

Also, the chuck is a 5/8" Rohn, and 1/8" seemed a bit small for it. I worried about bit wander if bit is too skinny and too long at the same time.

The pilot holes come out fine with 11/64". But how many intermediate steps / diameters should be drilled after the pilot hole before moving to the final 1/2" diameter?

From this thread, it sounds like maybe one step... perhaps a 1/4" or thereabouts, and then go for final.

With the tooling I have described, is the advice to only do one step still applicable?

Thanks!

 

[CapriMikeC]

Generally, drills are not good at opening existing holes. This is because the drill point creates stability. This is why drills are prone to chatter entering a hole, only the outer corners are cutting.

The short answer is to get to final size in the fewest steps your drills torque and setup rigidity will allow.

 

[MushCreek]

I would use a center drill (not all the way through), and then go right to the 1/2" bit.

 

[All]

I would use a center drill (not all the way through), and then go right to the 1/2" bit.

Lacking a center drill, would it be preferable to stop my pilot short of punching all the way through, so as to leave a "bowl" to retain the cutting oil (RapidTap) and prevent it from just dropping out of the bottom of a fully open pilot hole?

By the way, I decided to increase the size of the pilot to 1/4", so as to reduce the number of steps by one.

Now, I'm wondering if I should depth stop the 1/4" pilot, to mimic some of the benefits of a center drill that I do not have?

 

[ez-duzit]

Get rid of the X-Y table. And keep large "shims" of various thickness (plywood and lumber) to get your workpiece or vise to the correct height so you never again have to compromise your drill size.

Use the large Vise-Grip clamps to quickly secure the drill press vise to the table. Go directly to the finish size drill bit, now that you have a pilot hole already drilled. No need for steps, unless the piece is very thin, in which case you should use a step drill.

 

[whateg01]

That drill press will do it in one shot most likely. However a pilot hole is fine to keep the drill centered. At 150 rpm is not going to be bouncing all over the place

 

[All]

Get rid of the X-Y table.

What problems do X-Y tables present that inspire your recommendation to get rid of it?

I've come to depend on the X-Y table for positioning adjustments and aligning the drill to the punch mark on the material.

What problems am I inviting by using an X-Y table?

And keep large "shims" of various thickness (plywood and lumber) to get your workpiece or vise to the correct height so you never again have to compromise your drill size.

Is the compressibility of plywood and lumber an issue when clamped?

I'm imagining getting the part and the drill bit inline, and then cinching it down, only to find that the voids in the plywood and the general softness of lumber would end up moving the part off axis to the quill travel when clamped tight. Is this imaginary scenario of any concern? Especially without an X-Y table to compensate for any positional shifts resulting from the compression of soft shims?

so you never again have to compromise your drill size.

What is the ideal initial pilot size diameter for drilling holes in mild steel of thicknesses between 1/4" through 1/2"?

Use the large Vise-Grip clamps to quickly secure the drill press vise to the table.

My table is a solid square T slot table, that doesn't accommodate the drill press vise grips that bolt through open slots in typical round type drill press tables. I currently am using a combination of step blocks and threaded T slot receivers, in combination with the slotted ears of the X-Y table, to secure the X-Y table to the drill press table.

Moreover, the working surface of the X-Y table is also a solid T slot arrangement, and the block vice is likewise secured with a combination of threaded T slot nuts, and bolts through the bottom of the block vice, in combination with step blocks to resist and vice shifting.

Are vice grips made for T slot tables?

Go directly to the finish size drill bit, now that you have a pilot hole already drilled.
No need for steps, unless the piece is very thin, in which case you should use a step drill.

Thanks. This is consistent with the consensus of most respondents, and is the direction I clearly need to shift towards.

 

[cnc-me]

Make yourself a master and just use a transfer punch to set all the hole locations,
most likely will be faster than messing around with stops & fences and the like.
Punch them all, then just drill all the punch marks.
No drill bushings, and no drilling through the master that wears out the holes in the master.
Works great on low production parts like this.

 

[ez-duzit]

What problems do X-Y tables present that inspire your recommendation to get rid of it?...

I cannot imagine a more cumbersome arrangement than an X-Y table, permanently attached to the drill press table, when trying to align the bit to a center-punched hole. I would change careers rather than have to deal with such nonsense. Very curious to know who you learned this technique from. Surely not from a professional. It takes only a split second to line it up when you can freely slide the workpiece around.

 

[whateg01]

I cannot imagine a more cumbersome arrangement than an X-Y table, permanently attached to the drill press table, when trying to align the bit to a center-punched hole. I would change careers rather than have to deal with such nonsense. Very curious to know who you learned this technique from. Surely not from a professional. It takes only a split second to line it up when you can freely slide the workpiece around.

I rather like my xy table. Most stuff gets set on top of it but if I'm drilling a 1" hole in something, it's nice to know it's not going anywhere.

 

[ez-duzit]

...it's nice to know it's not going anywhere.

That's what clamps and vises are for.

 

[Wamsutta]

What you need is an automatic center punch and a pilot drill to start with.

 

[ez-duzit]

Here are 3 of my drill presses. If you zoom in you will also see 3 drill press vises, a tapping machine, stacks of "shims" and, on the left, some of the Vise-Grip clamps used for securing work to the DP tables. Though a bit cluttered and perhaps cramped, what you won't see is any Mickey Mouse BS that interferes with actually doing the job drill presses are required to do. This is a real working shop.

The leftmost DP is normally setup for highest speed. The rightmost DP is normally setup for lowest speed. The center DP usually has a countersink installed. This saves me time. The drawers contain drills, cutters, hole saws, taps & dies, etc.

 

[whateg01]

That's what clamps and vises are for.

Don't need them. I drop the work in the open xy vise and it just sits there. Only thing I have to do is make sure the work doesn't climb the drill.

 

[MushCreek]

I do most of my drilling on a Bridgeport mill, in essence, an XY table. I rarely lay anything out. I just pick up a '0' location and go from there for the various holes a part may have. Quick 'n dirty holes are usually done with a hand drill. I have a drill press, but I usually just keep a countersink in it for deburring holes. The set-up and the tools you use are all based on the accuracy required. I've done super-accurate holes in a jig bore by drilling holes, boring them to correct location and alignment, then reaming them, and possible even honing them afterwards. I've also 'drilled' holes with a cutting torch.