Sheet Metal Circle cutter for your drill press or mill


Small shops that do a variety of work in sheet metal have frequent use for circle cutters of the type that can be driven by a drill press. Home craftsmen also find use for these cutters in toymaking and ornamental metalwork. Pictured are two designs, one made from aluminum alloy especially for light work in wood, hardboard, plastics and soft metals, the other for the heavy-duty jobs in metals. The latter type, shown in Fig. 1 and pictured in use in Fig. 2, is fully detailed in Fig. 6. The shank is machined with a No. 2 Morse taper to fit a drill-press spindle, or sleeve, and it also is turned with an integral pilot. The lightweight job detailed in Figs. 3 and 5 and pictured in operation in Fig. 4, clamps directly to the taper spindle of the drill press into which the pilot drill, of the tapered-shank type, is fitted.

Although the best workmanship would require that the square holes in the shank and tool-holder arm, Fig. 6, be broached, it is possible to drill holes and square them with a file with sufficient accuracy. However, the tool-holder arm must be a smooth, sliding fit in the squared hole in the shank to prevent chattering in heavy cuts. The tool-holder arm, Figs. 1 and 6. is threaded its full length and flats are milled on the four sides, bringing the dimension across the flats to 5/8 in. The length of the arm gives a maximum radius adjustment of approximately 5 in. The lightweight cutter, Figs. 3. 4 and 5, does an exceptionally smooth, clean job on a variety of materials. When carefully made, it is practically chatterproof. Both the cutting tool and the tool-holder arm are held in place with binding clamps of special design and these two parts are attached to the taper sleeve with a binding clamp of sufficient length to hold the parts in exact alignment. Note that the cutting bit is supported in a groove milled across the face of the binding-clamp seat and that the groove is slightly less than 1/4 in. deep, Fig. 3. This allowance is necessary to permit the clamp to seat the bit firmly. The upper details in Fig. 5 show how to grind the bit for cutting holes and blanks in thin material. When ground for hole cutting, the bit leaves the outer edge smooth. When ground for blank cutting, the inner edge of the cut is smooth. For work in metals, the speed of the cutter should not exceed 100 r.p.m.

Click images to enlarge.
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May 16th, 2012 by grail21 in How To, Tools | No Comments

Gas Fired Smelting Furnace

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I’ve always wanted to try out some casting, maybe at the next shopping. The making the furnace part looks fairly straightforward (there are tons of youtube videos on this as well) it’s the making the molds that looks incredibly time intensive. Still, doesn’t get much cooler than melting down a bunch of scrap and turning it into a cool part.

May 3rd, 2012 by grail21 in How To | No Comments

Motorcycle Gasket Basics


A typical bike engine contains around three litres of oil, and one of the biggest challenges to engineers over the years has been to keep that oil where it should be.

There are many joints between the various engine castings, and nearly every one needs some means of preventing fluids from escaping. In an ideal world, every joint face would be perfectly flat, smooth and perfectly aligned with its opposite number. Furthermore, when the bolts were tightened no distortion of the joint would take place and they would remain perfectly tightened throughout the life of the bike. Unfortunately, we do not live in an ideal world and this is where gaskets come in.

The aim of a gasket is to provide a little elasticity to absorb the imperfections found at the joint surfaces. Typically, gaskets are made from a mixture of fibres, such as paper or asbestos, held within synthetic rubber such as nitrile. Nowadays asbestos is no longer favoured and more use is made from up-todate materials such as carbon fibre, PTFE and Kevlar.

To read the rest of the article, download the pdf: Motorcycle Gaskets 101 PDF

April 6th, 2012 by grail21 in Uncategorized, How To | No Comments

Aligning Lathe Centers

April 4th, 2012 by grail21 in How To, YouTube & Internet Videos | No Comments

Machinist Gauge Blocks

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“Precision gauge blocks are used in all well equipped shops to establish basic measurements for the purpose of laying out and producing parts of identical size. When critical measurements are necessary in laying out work on which machine operations are to be held within extremely close limits, the use of gauge blocks speeds up the preliminary operations and practically eliminates the reworking of jobs due to faulty scales or an error in taking readings”

Click the images to read the whole article.

March 19th, 2012 by grail21 in How To | No Comments

How to read micrometers

March 12th, 2012 by grail21 in How To, YouTube & Internet Videos | No Comments

How To Rivet Aluminum

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Old school.

March 8th, 2012 by grail21 in How To | No Comments

Basic Sheet Metal Work

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February 17th, 2012 by grail21 in How To | Comment (1)

Finishing Metal Surfaces

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February 12th, 2012 by grail21 in How To | No Comments

Differential Gears for Dummies

Maybe not motorcycle specific, but great bit of mechanical knowledge thrown down in an easy to understand format.

February 6th, 2012 by grail21 in How To, Video | Comment (1)

Embossing / Hammer Crafting Sheet Metal

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Use your imagination and you’ll see the next hip trend in “chopper” gas tank design.

February 1st, 2012 by grail21 in How To | No Comments

Lathe How To

You or I will probably not need to machine a pulley anytime soon for moto use, but the principles and lathe work that our friend Tubalcain lays down are universally helpful.

January 30th, 2012 by grail21 in How To | No Comments

Portable Drill Bracket


This looks handy, need to make myself one of these.

January 25th, 2012 by grail21 in How To | No Comments

Tig Welding - Feeding the wire

January 18th, 2012 by grail21 in How To, Video | No Comments

Milling attachment for your lathe

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November 15th, 2011 by grail21 in How To | No Comments

Horizontal Band Saws - the return of TubalCain

It’s been a while since I posted some TubalCain videos, this time around he goes in depth with the horizontal metal band saw. This guy is such a wealth of information and incredibly passionate about metalwork. I could sit and watch these videos all day (I’ve done that on a few occasions). I hear he’s now compiled his videos into DVDs so you can watch them on your mega flat screeen instead of having to sit in front of the computer. But true to form in the effort of spreading knowledge, he’s keeping all his videos on youtube, free for anyone to watch and learn. Sit back and get schooled.

October 24th, 2011 by grail21 in How To, Video | Comments (6)

Milling 101


Download the PDF to get a basic intro into basic milling procedure.

Click this link to download the PDF: Milling_101.pdf

October 10th, 2011 by grail21 in How To | No Comments

Counterboring and Countersinking


Some basic info and troubleshooting tips for when your counterboring or countersinking.

Click the link to download the PDF: Counterboring.pdf

October 7th, 2011 by grail21 in How To | No Comments

Metal Fabrication 101: Sheet Metal


Check out this 70 page introduction to sheet metal work. Covers everything from forming, bending, rolling, using bending machines and wheels. Tons of info, especially useful to those just getting started out. Click the link below to download the PDF.

Click here to download: Sheet metal fabrication techniqes

October 5th, 2011 by grail21 in How To | Comment (1)

Material Removal Revisted


I had previously posted some of the info in this chapter as seperate jpgs, but there was some much to dig into, I figured it made more sense to just load the whole chapter as a PDF file. Click the link below for some schooling on cutting, filing, drilling, punching and a whole lot more.

Fabrication Techniques: Fabrication and Metalworking techniques - material removal

October 3rd, 2011 by grail21 in How To | No Comments