Pin Holes and Tubing, Drill bits

[mwb]

The 'thick wall tubing' you are looking for is call DOM - 'drawn over mandrel'. Any half decent steel supplier should stock it.

 

[wvpolekat]

You can use a decent hole saw. Depending on how many you need to drill...

I have a set of annular cutters/rotabroaches that cost me less than $100 and cut pretty good holes but don't do well in thicker material.

 

[Birdhunter1]

I have used a 1 1/4" bi metal lenox holesaw and probably bored 30 or 40 hole swith it in 1/2" steel. The teeth on it are still in great shape and the paint is only really wore off about 5/8-3/4" up the side. Drill with it slow and use oil, leaves the holes in good shape, maybe a tad ovesized, but clean.

 

[ampa]

I paid about $85 cdn plus tax for a little over an inch size drill bit and thought that to be kinda expensive....but it is a good drill bit made in the USA.....Ampa

 

[sizzami]

drilling large diameter holes in steel , is easily done with a hole saw and a generous drenching of water soluable oil , I just finished drilling 20 1.25 holes in 1/2 inch bar for the dump hoist I am building slow speed and be carefull not to let the teeth foul with fillings.
I used the same holesaw for all holes and all 20 took about an hour .

 

[TDVT]

In the past, I have used hole saws myself but you need to check out this excellent thread that addresses this very issue. I didn't know these cutters existed, but I am currently gathering stuff for my spring attachment builds so I've got a bunch of places bookmarked that I can share from my hours of surfing.


This place has pretty good prices on cutters, Light Tool Supply They also have they holder to mount a cutter in a drill press chuck. This places prices were OK too, also had the holder. MORE CUTTERS

As for tubing, DOM is available in pretty accurate inside diameters. Speedy Metals has the easiest to navigate list with OD & ID info & also sells by the inch. I did a search for pin clearances but I didn't copy/bookmark any info. It wasn't too hard to find though.

Good Luck!

 

[jmanatee2]

In the past, I have used hole saws myself but you need to check out this excellent thread that addresses this very issue. I didn't know these cutters existed, but I am currently gathering stuff for my spring attachment builds so I've got a bunch of places bookmarked that I can share from my hours of surfing.


This place has pretty good prices on cutters, Light Tool Supply They also have they holder to mount a cutter in a drill press chuck. This places prices were OK too, also had the holder. MORE CUTTERS

As for tubing, DOM is available in pretty accurate inside diameters. Speedy Metals has the easiest to navigate list with OD & ID info & also sells by the inch. I did a search for pin clearances but I didn't copy/bookmark any info. It wasn't too hard to find though.

Good Luck!

Wow there is some great information there. I really like the point he made about using the O/A or plasma to make a hole big enough for a piece of DOM tubing and then welding that back in. Only problem I see with that is accuracy of lining things up.

Have you tried the Annular bits yet? How big is your drill press? HP?

I know the bigger you drill the slower you want the cutter turning (I assume because of heat) What is the max you would want to spin a say a 1.5" bit either annular or twist bit?

 

[moe7404]

when you use a hole saw. drill a center hole that fits the hole saw center. run the saw to touch the metal, just touch to get a good mark. then use a 1/8 drill to put the 1/8 holes partly in the mark of the large drill mark, but not outside of the mark, all the way through, all around the large dia. do at least 5-7 small holes. these will let the chips fall a way, use the hole saw dry.

 

[LD1]

Wow there is some great information there. I really like the point he made about using the O/A or plasma to make a hole big enough for a piece of DOM tubing and then welding that back in. Only problem I see with that is accuracy of lining things up.

Have you tried the Annular bits yet? How big is your drill press? HP?

I know the bigger you drill the slower you want the cutter turning (I assume because of heat) What is the max you would want to spin a say a 1.5" bit either annular or twist bit?

Let me start by saying that I am not a machinest by trade. Just a DIY'er.

I would probabally spin a 1.5" bit in a drillpress at ~200rpm.

And the bigger bits have to spin slower because the outer edge is spinning at many more inches per minute than a smaller bit. At least this is what I have been told.

For example, a 1/4" @ 1000RPM

circumfrence of 1/4" is .785 multiply that by 1000rpm and you are at 785 inches per minute.

A 1.5" bit @ 200 RPM is 942 ipm.

Same is true on a lathe. Larger diameter requires slower RPM. It is more about surface speed than RPM:thumbsup:

 

[SixHoeBob]

A magnetic drill press is the answer. I bought a set of bits (.5" to 1" annular cutters) for 175.00 on-line. Soon as I can find $900 to $1400 extra laying around, I will be getting the mag drill.:thumbsup: Until then, I'll mark holes and somebody else can drill them.

Reaming the two 3.25" holes to fit the O.D. of the seamless tubing took about two hours. I did not force the carbide burr/die grinder, so the burr showed no real wear. Machine shop might have charged $20-$30? I would have saved time and wear on my tools.

The other holes I had in stock in the form of 1"x3" flat bar with a 1 3/8 hole in each end, that I bought years ago at a sale. I designed the project around the materials on hand. I used 1.25 round stock for pins. The thumb by nature will get some abuse, so the 1/8" slop is about right. Plus it is easier to align the holes when installing and removing the 400 lb thumb and 200 lb brace.
Some use of attached lifting eyes and a come-along occurs.

When welding shrinkage will occur. The idea is to balance the welds as so that the shrinkage is canceled out. Short beads on alternate sides, alternate ends,
flip project and weld backside, alternating sides, basically weld all over the project. Weld all the corners and details, and then finish the middle areas. Avoid excessive welding, not all seams need to be continuous welds. More welds are not always better, they just add to shrinkage and distortion.