What is the best hole cutter?

We design and develop hole cutting tools for the professional contractor which make hole cutting faster, easier, and safer. These same capabilities are valuable to the Do It Yourself homeowner undertaking a project with many holes or where the risk or cost of accidental damage is high.

People ask us what is the best hole cutter and in order to answer I need to know hole large the hole will be and the type of material being cut and how deep the hole needs to be. Each of these factors determines what hole cutter is going to work the best. For holes smaller than 5/8 inches in diameter in most materials a drill bit is going to work better than a hole cutter and the type of bit depends upon the type of material as different bits are needed for metal, masonry, tile and glass, wood, and plastics. With masonry and concrete drill bits are often the best tool for holes up to 1-1/2″ in diameter.

The larger the hole the more torque is required from the drill and the more the efficiency of the hole cutter determines how big a hole can be made with a hand held drill, the drill power required, and the risk of backlash also increases. Choice of the best hole cutter for the hole size, depth, and material to be cut make a great difference in the drill power needed and the speed at which a hole can be bored. This in turn determines the minimum requirements of the electric drill that can be used.

It is surprising to most but the wrong choice of hole cutter can waste 90% of the power from the electric drill and take up to 10 times as long to bore each and every hole. Anyone with experience using high speed steel and cobalt drill bits has seen this difference in performance first hand. With holes from 3/4 inch up to 6 inches most people will usually use a bi-metal hole saw without a second thought and regardless of whether they are drilling in soft wood, hard wood, engineered woods (TJI, chipboard, oriented strand board, plywood), Hardie and other fiber cement board products, fiberglass, or plastics. This is a mistake.

Although bi-metal hole saws are the cheapest hole cutter available they are only well suited for drilling in mild steel that is 1/4″ or less in thickness. For any other material they are a poor choice and often a much more expensive choice on a basis of holes drilled per dollar spent, not even considering the much longer time required to drill the holes and to remove the cut slug from the hole saw.

Big gullet hole cutters have multiple large teeth instead of the many tiny teeth of a hole saw. The teeth on these hole cutters extends past the inner and outer side walls of the hole cutter and this eliminates side wall friction as the hole cutter cuts. All the power of the drill goes into cutting instead of burning the workpiece. These big gullet hole cutters, like the Blue Boar TCT, will enable a drill to cut a hole 3 times as large and in 1/10th the time as with a bi-metal hole saw with the same drill. This makes it practical to use even a 18 volt cordless drill to bore holes 6 inches in diameter in materials over an inch thick.

Some of the big gullet hole saws, like the Milwaukee Tools’ Big Hawg hole cutters use high speed steel teeth. These resist nail impact very well but dull quickly when used in engineered wood products, like MDF and particle board, and are not the best choice for abrasive materials such as fiber cement board, sheetrock, plaster, tile backer board, or fiberglass. For these harder materials the much harder tungsten carbide teeth will perform much better and stay sharp longer. With more than 5,000 different grades of tungsten carbide the manufacturer needs to match the grade to the materials that will be cut with the TCT hole cutter.

To summarize:

  • Holes smaller than 3/4″ in materials other than concrete use a drill bit (wood spade, HSS or cobalt, diamond)
  • Holes smaller than 1-1/2″ concrete use a carbide tipped masonry drill bit
  • Holes 3/4″ up to 8 inches diameter in sheet metal or thin mild steel plate use a bi-metal hole saw
  • Holes 3/4″ up to 8 inches diameter in stainless steel or thick metal plate use a TCT tungsten carbide hole cutter
  • Deep Holes 3/4″ up to 7 inches in diameter in wood, fiber cement board, fiberglass, sheetrock, plaster, MDF, chipboard, TJI, asbestos tile, non-fired clay tile, and stucco, use a TCT hole cutter with tungsten carbide teeth
  • Holes to 1-1/8″ deep and 1-7/8″ to 17″ diameter in wood, sheetrock, plaster, fiber cement board, fiberglass, MDF, chipboard, TJI, asbestos tile, plastics, rubber, acoustic ceiling tile, Formica, FRP, and similar materials use an adjustable hole cutter.

There are different quality and performance levels within these groups of hole cutters but the first step is to pick the right type for the job based on the material type and thickness and the hole size needed. The more holes you make the more time and money you will save by using the right type of hole cutter for the job.

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Hole Pro X-230 & a Toilet Closet Flange Fix

A common problem when laying new floor tile is the change in elevation that occurs and results in the toilet sitting too far above the closet flange. Some people use a double wax seal and this may work but I wanted to raise the closet flange for the toilet instead. I needed to replace the plastic flange as when the tile was put into place the worker had pushed thinset underneath and the thinset pushed up the flange at certain points to where there was not longer a flat surface for the wax ring and the toilet rocked.

My bathroom situation was compounded by the original contractor having added particle board to raise the elevation of the vinyl flooring to the same height as the adjoining bedroom carpet on padding. The new tile sat one full inch above the original plywood subflooring. I decided to remove the excess tile and the particle board and create a flat surface to add a spacer and then the new metal toilet flange.

I thought long and hard about how to remove the tile and thinset around and underneath the closet flange. I tried using a hammer and chisel but made little progress. I thought about using a hammer drill but was worried about cracking the tile and making the job even bigger. At some point I decided to try grinding the thinset and tile down using a small 4.5 inch angle grinder. I bought a dtec brand continuous rim diamond blade that has a “turbo” edge for faster material removal. It was not expensive and worth a try.

I first tried using the angle grinder with the dtec diamond blade like a cut-off blade with the grinder at a 90 degree angle to the tile. It was easy to control the dtec blade thanks to the continuous rim. It was much easier to control than a grinding wheel or a cut-off blade so my choice was a good one.

At some point I realized that the grinder and blade would work better if I used it like a plunge router with the tool parallel to the tile and gradully lowering the diamond blade to remove first the tile and then the thinset and finally the particle board until I was down to the plywood subflooring.

This approach made it very easy to control the grinder and cut exactly where needed.

The result is shown in the picture with the tile cut-out shown along with a blue circle to show how round an opening I was able to create for the new toilet flange. The ragged hole created by the original rough plumber (and rough is an apt description) was clearly made by a sawzall. I have known plumbers who say they don’t need a large hole saw and can make any hole they need with a reciprocating saw and save time. I doubt they save much time and they certainly leave a poor support for the closet flange (and a lot of drafts and pest entry points from sink drains in wall openings as well).

The next step was to add one or more spacers. I say one or more as the standard ones I found at a local builder supply store was 0.4 inches thick and are meant to be stacked with a layer of adhesive caulk between each one. As the closet flange is designed to sit on the subflooring I decided to instead make a spacer using a scrap piece of inch thick plywood subflooring. I needed an outside diameter for the spacer ring of 7 inches and an inside diameter of 5 inches. If you think that this was a more difficult and time consuming approach you would be mistaken.

Since first adding a Hole Pro adjustable hole cutter to my home shop I have found it makes fast work of projects that would otherwise take much more time and effort. I took my Hole Pro X-230 which cuts holes from 1-7/8″ up to 9″ in diameter and inserted it into my little 1/2 HP drill press set one blade at 5″ and the second blade at 7″ and then clamped down the scrap piece of inch thick subflooring. Even with the moderately powered drill press in a couple minutes I had the ring cut out from the plywood and had my spacer in hand.

I used a waterproof wood glue and placed the plywood spacer ring into the opening and on the subflooring.

Last step was to take some 2-1/” long #12 screws and drive them through the new toilet flange and the plywood spacer and into the plywood subflooring.
The end result was a closet flange that is 1/4″ proud of the tile floor.

I put down a single wax ring, mounted and bolted down the toilet and it fit perfectly. Perfect seal and no rocking and no gap between the toilet’s base and the tile floor.

Some may question using a wood spacer but the original subflooring was the same type of plywood with the same type of glue between the wood layers and provided a more solid support and better holding for the wood screws. I have read of people recommending the use of spacers to level a toilet over the flange and to then caulk with standard caulk or even thinset. I do not view this as a sensible approach. If there is water leakage around the flange I want to see it coming out from underneath the toilet and not having it sit and gradually seep down through the wood subflooring which is a sure recipe for dry rot and a much bigger and more costly repair job in the future.

I spent more time researching possible approaches to take than I did actually doing the work. It took less than an hour with the angle grinder and the dtec diamond blade to correct the work of the tile setter. It took less than 10 minutes in total to make the wood spacer (though luckily I had the scrap piece of inch thick subflooring at hand). Gluing, pre-drilling the holes, and screwing down the closet flange took about 15 minutes. Add in 30 minutes of setup and cleanup time. Next time it will go a lot faster and I know I will be using the angle grinder with the dtec diamond blade and the Hole Pro X-230 to do it quickly and do it right.

Only bad part is that all my handiwork is completely out of sight – but I can live with that.

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Cutting holes in plaster ceilings

There are many times when one or more holes need to be made in a plaster ceiling, whether for recessed light cans, audio speakers, a heating or air conditioning duct, or to add a ceiling fan. Plaster ceilings have been done in different ways in different parts of the country and at different times. After 1950 most plaster ceilings have a metal lath. In prior years the lath could be metal, chicken wire, or wood. In many cases the nails that originally held the pieces of lath in place have largely disappeared from corrosion over the years.

We recommend treating the plaster ceiling hole cutting operation as a two stage process. First cut the plaster and remove the plug. Second cut the lath using the hole in the plaster as a guide. The Hole Pro adjustable hole cutters make a clean straight cutout hole in the plaster for the can light or ceiling speaker and with the straight edge the grill or trim rings will sit flush against the surface of the ceiling. With the circular scoring motion of the tungsten carbide cutting blades the two layers of the plaster are not likely to separate and cause a crack in the ceiling (which can be very expensive to repair).

The best tool for cutting the lath depends upon the material used. For standard metal lath a carbide grit reciprocating saw blade works very well. For wood lath a fine tooth bi-metal reciprocating saw blade usually works the best. For chicken wire it is best to use diagonal cutting pliers (dikes) or snips to cut the wire lath.

In theory it would be simpler to use a continuous edge tungsten carbide rim grit hole saw and cut through all three layers. There good reasons why this is often not the case. It comes down to cost. Each size of carbide grit hole saw costs between $45 and $80 depending upon the brand and the hole saw only works for one size hole. The sizes provided by all manufacturers (Milwaukee, Greenlee, MK Morse, Lenox) are limited to 3-3/8″, 4-3/8″, 5-3/8″, 6-3/8″, 6-5/8″, 6-7/8″. With more than 20 common recessed can light cutout sizes needed the sizes available are seldom going to work.

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Installing Recessed Can Lights in Ceilings

Installing recessed can lights or high hats in ceilings has gotten more complicated with all the new sizes of LED, PAR, and CFL light fixtures. Instead of three common hole cutout sizes for the majority of recessed can lights (6-3/8, 6-5/8, 6-7/8 inches, there are now more than 27 common sizes and very few in these traditional diameters.

For example the Halo brand of recessed light cans sold by Amazon, Lowe’s, Home Depot, and others, have manufacturer recommended cutout hole sizes of 3-3/4″, 4-1/4″, 5-1/2″, 6-1/4″, 6-7/16″ for the different size can lights. Another common recessed can light manufacturer is Juno and for their can lights one needs cutout holes of 3-1/4″, 4-3/8″, 5-1/2″ 6-3/4″, 6-7/8″. And this is just for the residential high hats or recessed ceiling lights. Commercial can lights can require cutout holes larger than 8 inches in diameter. So one can spend hundreds of dollars on continuous rim grit hole saws and still not have the right hole saw sizes for the most common can lights. Or for $139 a Hole Pro model X-230 hole cutter can cut any size cutout hole needed from 1-7/8 to 9 inches in diameter.

There are a number of important advantages to using a Hole Pro adjustable hole cutter to make the cutout holes for recessed can lights (or downlights). First is the ability to make the exact size hole needed in whatever ceiling material is to be cut. For thick plaster a slightly larger cutout hole may be needed to provide room for pushing up a remodel style can light into the ceiling space. With soft sheetrock a close fit may be needed with smaller LED can lights like the 3 inch and 4 inch models from Utilitech sold by Lowe’s and the Con-Tech fixtures sold by Home Depot.

Most of the manufactures have stopped publishing the cutout dimensions so one does not the exact hole size needed until the light cans have been purchased and one can measure the template in the box. Often the template is the same for all models from the manufacturer and may be too small for some of the variations, especially with the remodel light cans. With the remodel or retrofit type of recessed ceiling can light the entire fixture has to slip through the opening and often the size of the opening is dictated by the arm that attaches the fixture to the electrical junction box. Some designs, like the Halo in particular, make it much more difficult to insert the can light assembly.

The Halo H5RICAT (“5″ indicates 5” fixture, “R” indicates remodel/retrofit type and the “I” indicates that it is OK for direct contact with insulation) comes with a template for a 5-1/2 inch size cutout hole. In an actual installation the tape that is wrapped around the light can to help make a good air seal increases the outer diameter of the light can so it requires a 5-5/8″ cutout at a bare minimum and 5-11/16 inches is a safer size to minimize damageĀ  to the sheetrock.

The “air tight” ceiling fixtures when installed properly can significantly reduce loss of heated air from living spaces up into the attic. All the air tight fixtures I have examined from the major suppliers are cheaply modified with a thin strip of insulating tape that probably adds 2 cents to the manufacturing cost and does a poor job of providing an air seal. A foam sealant would do a much better job.

The H750RICAT is supposed to fit through a 6-1/4″ cutout hole cut but actually the can light needs a hole at least 6-3/8 inches in diameter for the can portion of the fixture.

The Halo H750RICAT recessed remodel light can is most easily installed through a 6-1/2 inch opening so that the junction box and can cylinder and the thick arm bracket (outlined in red in the picture) all fit through the opening in the ceiling.

Some of the less expensive remodel type can lights have a thin metal arm that is 1/8″ thick strap steel and which makes them much easier to insert in the ceiling opening. This thin bracket is shown in the picture outlined in red.

When making the cutout holes for recessed can lights the Hole Pro adjustable hole cutter makes it faster and a lot safer with its adjustable cutting depth control The cutting depth can be set so that the blades only cut the sheetrock or plaster or tongue and groove wood ceiling and nothing more. No worries about accidentally cutting an electrical wire, low voltage audio wire, or plumbing pipe in the ceiling space and turning a small project into an expensive repair job.

The Hole Pro hole cutters also save a lot of time when installing downlights. The hole can be cut faster than a cutout circle can be drawn on the ceiling with the template. It is easy to cut a perfect round hole even with only one hand to hold the drill with the hole cutter when high up on a ladder. The ABS plastic shield is ball bearing mounted so only the hole cutter spins and all the dust and shavings and the cut plug all stay in the shield. Invert the shield over a bucket and everything falls out and the hole cutter is ready for the next hole.

A lot of time is saved when one only needs to place the hole cutter’s pilot drill bit in the center of the spot for the cutout and start to drill. No need to move furniture or lay out a tarp or get out the shop vacuum.

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Adjustable Hole Cutters

Although adjustable hole cutters have been in use for many years, the new style with a clear plastic shield for use in a hand drill is a relatively recent development. The earliest models were designs that had a single cutting blade on a bar that could be adjusted for different size holes and different lengths of bars to add to the cutting bar to provide for better balance. The twin blade design of the Hole Pro adjustable hole cutters is a big improvement over the single blade designs in terms of performance and durability.

With the twin blade design there are no balance bars needed and these bars with their small mounting threads are one of the key weaknesses of the single blade adjustable hole cutters. When the bars break off with the attachment threads inside the bar the hole cutter is toast. A second problem is that the balance bars do not completely balance the weight of the cutting blade and so there is a wobble action when cutting. When cutting overhead with a sheetrock or plaster ceiling the dust will often get between the center shaft and the ball bearing of the shield and cause it to jam. These problems are avoided completely with the twin blade Hole Pro design.

There are important advantages of the adjustable hole cutters, some quite obvious and others not. Being able to adjust to the exact hole size needed is increasingly important with so little standardization and so many products coming into the USA from overseas with measurements in millimeters. Instead of a 4 inch (102mm hole) a can light may need a 100mm or 105mm cutout hole. With recessed can lights there are more than 20 different cutout hole sizes needed.

Bi-metal hole saw sizes larger than 6 inches in diameter are not widely sold as no hand held drill can use them in wood. With the Hole Pro adjustable hole cutters a drill can make a hole 6 times as large as with a hole saw and make it the exact size needed. Although the cost is higher initially, being able to change out the blades in seconds and cut another 100 holes saves money in the long run and makes it easy to keep a spare set in the carry case that comes with the hole cutters.

For some materials like soft woods, veneers, plastics, and rubber, the high speed steel make finer and smoother cuts. With hard and with abrasive materials like sheetrock and plaster and Hardie and other fiber cement board products, the tungsten carbide teeth provide much better longevity. With only the two cutting blades making contact with the work piece the torque needed is much less and it is easy to cut delicate or heat sensitive materials like plastics and rubber.

Not obvious but a big advantage of the tough ABS composite plastic dust shield is that it insures a straight in cut like having a portable drill press, and it provides for control of the cutting depth. The orange knob on the hole cutter shaft can be set to limit the cutting depth to 3/4 inch and when cutting through a wall or ceiling the user knows they are much less likely to accidentally cut an electrical wire or plumbing line than when using a jab saw or a reciprocating saw with 3 inch deep saw cuts.The circular motion of the hole cutter is also less likely to crack plaster ceilings.

We have added a vacuum adapter fitting that can be used with any of the Hole Pro shields and provides for easy attachment of a HEPA vacuum to meet the new EPA lead paint rules. This is also a good feature for use when cutting holes in areas where there is the possibility of asbestos or other hazardous substance on the surface or in the ceiling or wall spaces.

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