Drill Press Torque Issues

[niferous]

We are trying to cut these large pipe wipers at my shop and I thought a radial drill press would be a good option. They are just buna rubber and they come with a 2-3/8" hole in the center. Our customers use them on drilling rigs to wipe the drilling mud residue off the pipe as it comes up out of the hole. Most want them cut to 4-1/2" or 5".

Up until now we've always used a little table that has an arm with a blade attached and then you just cut through the wiper. Besides being very time consuming only a few companies make them and they are very expensive. The blades break often and they are just generally a pain in the ****.

We tried cutting them today with the machine set on the slowest speed and used some Liquid Wrench lubricating oil as lube. It did cut the wiper but it was extremely slow and kept binding up. Would switching to a more powerful motor help us? Also we are going to get some heavier oil like a motor oil to see if that helps.

The wiper on the drill press:


The motor on the drill press. It's a little fuzzy but basically it's just a little half horse power motor:


Thanks in advance for any help.

 

[wblake]

you would need low rpm high torque, maybe trying a 3 phase motor..if you can get low enough rpm

 

[Mohawk Dave]

More power, even a GOOD 3/4hp would do it. 5" hole is a lot of material at once,,,even if it's rubber.

I would *think* that you want as large as teeth as you can get for the blade. Fine tooth would gum up and spin.

As far as radial DP goes, only if you need access. But it looks like a 15-20" DP would work for you. I could recommend a JET 1hp 1" 20" DP for $1,100 like mine or I would also recommend an HF 16spd for $300ish...which I think would be just fine. You aren't exactly building space shuttles, and I've used the HF...it does just fine. Or buy a used biggun off CL.

Look into different 4.5"-5" blades. I shall google as well.

 

[A_Pmech]

That little machine just isn't up to the task of production sawing out those wipers. Rubber takes a fair amount of power to cut and likes to seize up. Even if you do change the motor to something larger, I doubt you'll get the power to the spindle before the belt slips.

 

[rancherbill]

You might have one or more problems.

It is not the machine.

The hole saw does not have clearance for the chips to get out. Kerf is width of the saw blade. You might be using a metal blade that has a much narrower kerf. New blades have smaller kerfs to allow for quicker drilling. You need an old style wood blade with wide blade to let the chips get out.

Peck drill, which is drill 1/16", raise the drill to get the chips out and then do it again. If you try to go 1/4" at once it will get bound up.

Check your speed. Here's a chart to give you and idea. Plastic is much slower than metal.

 

[91bronc300]

You would need a lot more than a half HP but what about a hole saw with very small or no teeth and running at a high speed in order to liquify/soften the rubber and push through it rather than cut chips?

 

[zkling]

You are asking alot of that machine overall. Not just torque, but taper, belts and overall flex. I'm not sure if it would work on something that thick or druometer, but if you have a good size press you may be able to make a cutting die and press cut them.

 

[A_Pmech]

You are asking alot of that machine overall. Not just torque, but taper, belts and overall flex. I'm not sure if it would work on something that thick or druometer, but if you have a good size press you may be able to make a cutting die and press cut them.

I was thinking along the same lines as well, but with the thickness of the rubber I couldn't think of a punch design that would work. Then, after you posted, I thought of a way. He wouldn't even need a press with the one that popped into my head.

 

[rlitman]

You need an entirely different type of hole saw. Rubber is a difficult animal to cut, and trying to cut it with something made for wood/metal is asking for trouble.

The first thing that comes to mind is that your hole saw would need much deeper gullets and less TPI to effectively remove the chips. But to even get chips, you either need a cutter moving ridiculously fast (neither realistic nor safe on such a large hole saw), or incredibly sharp (also not realistic, because the necessarily steep rake would be dangerously grabby).

In fact, I think that the entire hole saw idea is a loser.

If they weren't so darned thick, I'd suggest you use a solid carbide spiral up-cut bit in a router with a circle template. But I wouldn't extend a bit more than 4x its diameter, so that limits you to 2" thick rubber with a 1/2" bit (unless you cut from both sides, but that adds alignment issues). More than that and you've left router territory and want to step up to a vertical mill.

It looks like there is a slot in these from the outside edge that can get you into the middle. A sufficiently powerful band saw could be great on these, and with the right jigging, it could potentially get you an acceptably round hole (blade cup might actually work to your favor if you cut in the correct direction). You would need a blade with sufficient kerf to deal with the fact that it is rubber. I have some carbide tipped resaw blades for my 14" Delta that I believe would be great on this.

 

[Jswain]

Not helping your problem any but just curious as to why they can't order them with a 5" hole in it already? We order a few a week on our rig up here in Canuckadia and it is obvious that they are formed with the correct hole already in place.

Also if the oil company doesn't mind they also make them in one solid piece without the split that are half the thickness but work just as good if not better, would save you half the time drilling them out.