Denker's Metalworking Project Page


Contents:

 9" Disk Sander

 Boring Head

 Cutoff fixture

 Lathe Grinder fixture

 Mill High Speed Spindle

 Index Fixture

 Lathe Ball & Radius Fixture

 Lathe Carriage Micro-Stop

 Lathe Knurl Fixture

 Micro Drill-tap Adapter

 Quick Change Tool Post Set (Changed)

 Right Angle Mill Attachment

 Sheetmetal Hand Brake

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9" Disk Sander

This was one of my very first projects. It is made mostly of wood but does have some .18" thick steel parts that I laser cut at work. I used a 1-horse 1725-RPM motor. It was originally made for wood but works very well on metal. I added the SCOTCH-BRITE deburring wheel later (runs about 3450 RPM) and it can be removed if necessary. The table can tilt down 45 and has a groove for a slide guide. This sander gets a lot of use.

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Boring Head

The workspace between the mini mill head and the worktable is quite limited. Because of this I use a set of screw machine drills which are shorter then normal jobber drills. I didn't want to by the common 2" boring head for the same reason - so I made my own. This head was made from 1" x 2" steel bar and uses .375" diameter tools. It mounts in a .75" diameter holder and extends down from it about 2". It works for diameters up to about 2". This design has a socket head cap screw that must be loosened to make adjustments then tightened again.

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Cutoff fixture

Unless you want to buy all your hardware to needed size, you will need to cutoff bolts, pins, and shafts from time to time. I was doing it a lot, so I came up with this fixture. It uses a 26-RPM geared motor turning a 1/2" chuck and a DREMEL with a 1.5" cutoff wheel. (The one in the picture is wore down) I can move the cutoff wheel away from the chuck about 3" so fairly long parts can be cut off. I have cut everything from brass screws to hardened round tool bits.

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Lathe Grinder fixture

When I need to cutoff something bigger, I use this fixture on the mini lathe. It uses a CRAFTSMAN tool grinder and it is quite big. (The tailstock must be removed) This thing runs at 25,000 RPM and can vibrate a bit so everything must be tight. TIP: place wet shop rags under the grinding area and on wear surfaces to catch the grinding dust - grinding dust and oiled machine wear surfaces don't mix. Clean and oil the machine when done!

In the next picture I am cutting off a hardened 1/2" bar using a 3" cutoff wheel. Also shown is a SCR motor speed controller.

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Mill High Speed Spindle

The CRAFTSMAN tool grinder used in the above project can also be used on the mini mill to make a high speed spindle. The spindle is mounted in a 3/4" R8 collet and the drawbar is replaced with a threaded .26" I.D. x .50" O.D. steel tube. The grinder and its mounting bracket are then mounted on top of the mill. I am using a SCR motor speed controller to controll the spindle speed. Notice I placed a lock on the mill power switch to make sure I don't mistakenly try to turn it on.

The next picture shows all the parts made for this project. I used ball bearings rated at 43,000 rpm for the spindle but they are quite small and I am not sure how well they are going to hold up. The collet and collet nut are purchased ROTO ZIP CT250 (.250" dia.) or CT125 (.125" dia.) replacement parts. The drive shaft that goes through the drawbar is .187" diameter. Plastic was used on the grinder mounting bracket to help reduce vibration.

The next picture shows the spindle in a 3/4" R8 collet with the hollow replacement drawbar attached.

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Index Fixture

If you want to make any kind of marked dials, it is nice to have an indexing fixture. This one was made using a purchased replacement lathe spindle, bearings and other parts in a surplus steel casting. (not available anymore) The index and vernier plates were laser cut at work and gives me 3 ranges to work with. (28, 360 and 200) I can also mount other index plates to it. The spindle can use a lathe chuck or MT3 collet so there is nice versatility. (also has a .81" diameter through hole) The marked dial on this fixture and many others were made using it. There are cheep 5C collet index fixtures available if all you want is the 360 step range or of course you can use a rotary table.

I also made the tailstock shown in the picture.

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Lathe Ball & Radius fixture

This is a ball and radius fixture I made for the lathe. It uses a .375" tool bit that can be set with a micro dial (.050" per rev.) and can handle parts up to about 2" in diameter. This is a good design for making ball ends but somewhat limited for large part radius edges and special radius shapes.

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Lathe Carriage Micro-Stop

Before I made this stop, I used a handwheel and dial on the leadscrew shaft or the compound rest to get the depth of bores etc. This works so much better. To use (with the machine off) I set the cut tool against the gauge surface of my part and with the micro-stop set to 1.000" bring it up against the carriage and lock it down. Then dial back the micro-stop the depth of the bore or cut and it's set. For more then 1", I use a spacer when setting it up. Both the lock lever and the stop use 1/4-20 L.H. threads. This design has a low profile and fits under the chip pan that I added to the carriage. I use this stop a lot!

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Lathe Knurl fixture

I have two knurl tools. A scissors type diamond pattern tool and this straight knurl fixture. I made this because I didn't want to buy another scissors tool, but for the mini lathe the scissors tooling works best. To keep compound slide screw forces to a minimum, I went with a bottom up design. This puts all the knurl pressure on the lathe bed.

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Micro Drill-tap Adapter

For small drill sizes you really need a micro drill adapter. The mini-mill has too much head weight to use with small drills. I made this one with a 1/4" chuck and with the addition of a reverse switch on the mill, I can use it with small taps too. (Spiral point taps in through holes) The outer shaft is .625" diameter and the inner shaft has .80" of spring loaded movement. A knurled aluminum collar pressed on a ball bearing is mounted just above the chuck for easy hand control. Above the bearing is a rubber o-ring to deaden any release shock.

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Quick Change Tool Post Set

One of the first things I made after building the mill was a set of quick-change tool holders and tool post for the mini lathe. I made these out of aluminum but some people would prefer steel. Aluminum works fine for the forces used on the mini lathe and is easier to machine. (wear hasn't been a problem)

Most holders are 1" x 1" x 2" and can be used with up to 3/8" tooling. One is made for a 1/2" high cutoff blade and one made for a 1/2" diameter homemade boring bar.

The next picture shows my two latest tool holders. The one on the right is a retractable threading tool. It can retract the cutting bit about .10" for the return trip to the start of the cut. This was an easy to build design and it works great. (It uses a .187" diameter tool bit)

The tool holder on the left is for a cutoff blade. It sets the blade at 14 for better cutoff action on steel and is mounted to a square bar for easy mounting in any tool holder.

A note on tool bits: I have come to realize that smaller is better! Only a small area of a tool bit is actually used when cutting and the smaller tool bits are far faster and easier to sharpen.

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Right Angle Mill Head Attachment

This project was done mainly to see if I could do it. It also required making a spindle collar for the mill so the angle attachment would have something to mount on. The attachment uses BOSTON 2:1 spiral bevel gears. The output shaft is a 1.25" diameter MT3 straight socket cut down to the desired length. That and ball bearings are put inside a surplus steel casting. (not available anymore) The output speed is half of the input so it doubles the mill output torque.

This attachment requires a mill reverse switch. In the next picture you can see I mounted it behind the control box. I had to flip the cover plate around so the power switch was on top. This picture also gives you a view of the spindle collar that was added. (replaced a plastic cover) When the angle attachment is not in use, I add a knurled ring to the bottom of the spindle for easier hand turning.

As long as I now have a right angle mill attachment, I made a 1" saw arbor and bearing block mount for the mill column. There is a lock lever on the block so it and the mill lock lever have to be tightened when in use. This is a little tricky to setup but it sure works nice.

The next picture shows its parts.

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Sheetmetal Hand Brake

This device is used to form sheetmetal and I use it to make guards and covers etc. This is a bit heavier duty then many out there you can buy. It will handle up to .060" steel or .080" aluminum. If the parts are not very wide, it will handle thicker material. I made it because I was a sheetmetal part fabrication engineer and I just had to have one, but it does get used.

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All pictures and content Copyright © 2007 2009 David Denker. All Rights Reserved.

Last Revised: June 2009