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MachinistBlog.com

Plans, projects and how-to's for home machinists

There just aren’t enough hours in the day

I know I haven’t added much content to MachinistBlog lately. I haven’t lost interest or permanently abandoned my self-imposed goal of trying to add at least one new post to the front page each week (on average). It’s just that I’ve been really busy and I have to make this web site a lower priority for now.

I’d love it if you could help me keep it from getting stale by becoming a guest blogger. You can write about almost anything that is metalworking, tool, or workshop related as long as you’re not doing it to promote a product or service. And don’t worry if you’re not a great writer because Nate, our copy editor, just told me he needs more to do. You could also do a photo essay if you want.

I’ve been busy for a quite a few reasons. The biggest one is that I’ve become very passionate about getting a maker space started and I built a web site for one. RochesterMakerSpace.org still has a lot of rough edges and it needs some more meat on its bones. So I wasn’t planning on publicly rolling it out this week but that’s what I did when a discussion about maker and hacker spaces came up in a discussion group I run. And now, ready or not, I need to keep moving forward with the project until we either get something going or determine that there’s not enough interest right now.

I’ve also been busy working on my CNC router again. I neglected it for at least several months and I wasn’t happy with myself for letting that happen. So I’ve been trying, not always successfully, to get at least one small thing done on it each day.

On most days I only have enough spare time to work on either it, this web site or some other project. I usually choose the router because I want to be someone who does things and not someone who just talks about doing things. I’ve finished making nearly all the parts for it and pretty soon it’ll just a matter of putting them all together, like a kit. So you should at least see some pictures of it later this month.

I’ve also been trying to find 6 hours each week for exercise. I ran or biked regularly until about 2 years ago when I quit almost completely because I was too busy with other things. Well, in early December I realized that I felt like crap, looked like crap and was risking serious health issues because I wasn’t exercising.

So I started going to the YMCA 3 times a week and mostly just walked as fast as I could around an indoor track. But it made a big difference in how I felt and a few months ago I started running again.

I’ve been a runner almost all my life but I gave it up about 5 years ago and switched to bicycling because I was afraid running would eventually ruin my knees. I’d never had any problems or injuries but I’m very tall so I already had a poor power-to-weight ratio to begin with, and like most people I was getting heavier as I got older.

But bicycling didn’t do it for me and I really missed running, especially each Spring when the weather began to get warm. So I pre-registered for my favorite 10K and started training on treadmills and cinder tracks because they put less stress on your knees than pavement.

Five years ago I could go out for a long fast run and it wouldn’t affect me very much afterwards. But that’s not true any more because I’m still out of shape, still at least 10 pounds heavier than I used to be and of course I’m older. Now a hard run can ruin me for the rest of the day, tiring me out so much that I spend my evening goofing off instead of trying to accomplish something useful. Hopefully I’ll get into better shape soon and that won’t be as much of a problem.

And finally, the arrival of warm weather brought more opportunities to spend time with friends and family. And I’ve always made doing that a top priority.

A New Netbook With An SSD

I haven’t added much to this blog lately because I’ve spent an enormous amount of my spare time in the last two weeks researching, buying, setting up and tweaking a new netbook to replace my two-year old 11.6-inch Acer Aspire, which was really starting to annoy me with its slowness. If I’d known what I’m about to tell you I could have probably extended its life for another year or two by replacing its hard drive with an SSD.

Update 04/16. I spent some time on the phone with HP this morning. My new netbook won’t turn on and they think it has a defective motherboard. Stuff like that happens and electronic devices are most likely to fail when they’re new. So I’m not going to criticize them about it.

They wanted me to send it to them for repair but I told them no. I specifically bought it from Amazon.com because I’d heard they make it very easy to return defective laptops or even ones you don’t like. That appears to be very true. It only took a few minutes to print out a UPS shipping label for free return shipping. I then went to order a replacement but found that in the last two weeks the price had gone up $35 to $410.

So I called Amazon. Actually, they called me in 5 minutes just like their web site said they would. They’re going to do an even exchange instead and they paid for overnight delivery so I get my replacement tomorrow. The call only took about 3 minutes and I obviously talked to someone located in the U.S. instead of India. Guess who made a very loyal friend today 🙂

I’m not as knowledgeable as I used to be, but I’m still a genuine computer geek and very picky when I buy a new laptop or build a new desk top computer.

My old Acer Aspire netbook was small and light so it was easy to keep it with me most of the time. And I didn’t feel embarrassed to pull it out in a diner and do some writing if inspiration came to me while I was having lunch. So I wanted to continue to own a small and light netbook.

I also wanted a very long battery life. I’d had a very bad experience with my first laptop, which I’d really struggled to buy when I was was young and poor. It was nearly useless because its battery lasted only 40 minutes even though it was advertised to last for 2 hours.

I’ve also been very bored while waiting in airports and on airplanes because I had a laptop with a dead or dying battery because I couldn’t an find an electrical outlet or they already had laptops plugged into them.

And lithium-ion batteries start losing their storage capacity from the very moment they’re manufactured. The amount varies but a good rule of thumb is they’ll lose at least 10% of their remaining capacity each year and it can be as much as 40%. The higher the temperature they’re used or stored at the faster they’ll lose it.

The battery in my old Acer was good for a solid 10 hours when it was new and after 2 years it will still last for at least 6. So I’ve never had to worry about finding an electrical outlet to plug it in to. Continue reading A New Netbook With An SSD

Why I Bought a Trailer Instead of a Truck

Some might not consider a utility trailer to be a tool but I do and it’s one of my most useful ones. This article describes why and reviews Harbor Freight’s 4×8-foot utility trailer.

I lost the ability to bring home full-size sheets of plywood and other large items, which I do often, when we replaced my wife’s mini-van with a small SUV about five years ago. I thought about buying a used pickup truck but I had a long commute and a perfectly good car that was paid for and got much better gas mileage than even a compact pickup would get. A truck wouldn’t get driven much it and it would take up a lot of room in our driveway. Worse, even an old rust-bucket would cost me thousands of dollars and I’d have reoccurring expenses for insurance, registration and maintenance. So I put a trailer hitch on my Camry and bought an inexpensive utility trailer from Harbor Freight instead.

“Basic” Cost

I’m not certain but I think I bought it on sale for about $225. They’re often on sale now for about $300 and you might be able to save an additional 20% with a coupon. The trailer hitch and wiring for my Toyota Camry cost another $300. The trailer comes without a deck so I also spent about $80 on a 3/4-inch thick sheet of exterior plywood, some paint to help protect it from the weather and a bunch of bolts, washers and Nyloc nuts to attach it to the trailer frame. With taxes, registration and an inspection sticker my total basic cost to get it on the road was about $650.

Accessories

Over time I added accessories Harbor Freight to my trailer to make it more useful and easier to use.

An assortment of ratcheting tie-down straps: I use wide heavy-duty straps for almost everything and I often use more than I need to because it’s not worth taking chances.

Swing back trailer jack (about $26 on sale): This must-have accessory keeps your trailer level when it’s unhitched and makes it easier to move.

Wooden Sides – homemade from 1×6 and 2×4 pressure-treated lumber (~$80): I still haven’t decided how to connect the sides together at the corners. If I need to I just run heavy-duty tie-down straps around the outside.

Six 1/2-inch forged D-rings and mounting hardware (~$45): These are mounted on the trailer’s deck at the corners and near the mid-point of each long side. They make it a lot easier to attach tie-downs. Without them you have to attach them to the underside of the trailer where they can be damaged by edges of the trailer. I used metal backing bars to keep the mounting bolts from pulling through the plywood deck. I also used Nyloc nuts so the bolts couldn’t become loose from vibration.

Spare tire ($50) and a spare tire carrier ($13): After five years I decided it would be wise to have a spare tire. I still need to buy a lug wrench and jack that I can keep with the trailer.

2-ton Shop Crane (~$160 /w coupon): I bought it to safely get a 400-pound jump shear on and off the trailer. I couldn’t have used it with a pickup truck because it wouldn’t have been able to lift it high enough to get it on the bed. Now that I have one I keep finding uses for it and friends who would like to borrow it.

Ramps (still to come): Even Harbor Freight’s ready-made ramps seem kind of pricey. So I’m probably going to fabricate my own attachments for planks. Ramps will make it easier for me to get lawn tractors, snow blowers and other items with wheels on and off the trailer.

Review

It’s light and easy to move

My trailer’s shipping weight is 159-pounds. It probably weighs about 250-pounds with a 3/4-inch thick plywood deck and all the accessories I’ve added to it. I’ve found it to be very easy to pull by hand even when it’s loaded and on gravel or grass. That’s really helpful because it’s very hard to back up with my car because it’s so short. I also can’t see it unless the sides are on it or something tall is sitting on it. So I often don’t even try to back it in, especially if I’m on a busy road. I just pull in, unhook the trailer and pull it by hand to where it has to go. To make it even easier I keep a loop of rope tied to the tongue.

The trailer’s light weight makes it very easy to hook it up because you can move the trailer to your hitch instead of having to back your vehicle up to it. I can have it completely hooked up and ready to go in less than 3 minutes (5 minutes if I have to turn my car around in the driveway).

It folds-up for storage

I took advantage of this feature to store my trailer against a stockade fence for a couple of winters. But I don’t do that anymore because now it gets used year-around. When folded it’s about 5-feet high and wide, and about 15-inches thick.

The trailer is hinged in the middle of the deck so the back half folds and lays on the front. The tongue is also hinged so it will  fold against the bottom when you pull a couple of pins. Once that’s done you can tip the whole trailer up so it sits on a couple of brackets near the fenders that each have two swivel wheels. The wheels on mine were plastic and the same kind you often see on office desk chairs. They probably would have been fine on asphalt or concrete but they didn’t last too long on the gravel next to my garage. After they broke I had to “walk” the trailer to move it.

One problem is the two halves won’t fold completely flat because the hinges can’t accommodate the 3/4-inch think plywood I used for the deck. They probably would have been fine if I’d used 5/8 or 1/2-inch but I wanted the extra strength and to be able to countersink the heads of the mounting bolts.

The hinges also occasionally cause some problems with the trailer lights by preventing the “ground” from getting back to the car, probably because of corrosion. I tried bypassing them with wire but for some reason that didn’t help. But it happens infrequently and if I drive it down the road for a mile or so the bouncing quickly wears away whatever rust or corrosion was causing the problem.

The trailer’s pretty stable when it’s folded up but it could hurt someone if it somehow fell over. So I always tied it to my fence. It also takes some strength to tip up and there’s a chance you could hurt your back or pinch your fingers.

It took awhile to assemble

The trailer has to be assembled and it probably took me at least 2 full days. The directions weren’t very good and I took apart and reassembled the trailer frame at least twice before I got it right. I had to go get a sheet of plywood for the deck and then drill and countersink holes for the mounting bolts and paint it before permanently mounting it. I also had to grease the wheel bearings, mount the lights and install the wiring harness.

Of course, after I was done I started noticing nice used full-assembled utility trailers that were for sale for about the same amount that I had invested in mine.

One Concern

I’ve been very happy with my trailer until just recently, although it’s not really the trailer’s fault. I’ve been thinking about buying an old Simplicity compact tractor to restore and the ones I’ve found so far on Craigslist have been at least 200 miles away. They’re heavy enough with accessories to approach the trailer’s 1200-pound load capacity. The trailer also has 12-inch Chinese made tires that are not suppose to exceed 55 mph. So I’m nervous about using it to pulling something heavy at high speeds for a long distance.

Rear-mounted Parting Tool Holder for Sherline Lathe

This is the rear-mounted parting tool holder for my Sherline lathe.  It’s based on a design that’s been around for decades and I made it about 12 years ago, before Sherline offered one for sale. It is just a block of 6061-T6 aluminum and it cost almost nothing to make. Further on you’ll find drawings that will help you make your own. The design could probably be adapted for 7×10/12 mini-lathes, which are notoriously bad at parting-off.

Yeah, I know its beat up and ugly but it is extremely solid and functions perfectly. As you know, a rear mounted parting tool pushes the carriage down instead of raising it up so rigidity is markedly enhanced. My parting tool does not chatter, dig in, or deflect. It cuts cleanly in all materials I have used it on, at speeds averaging 2-3 times normal turning speeds.

The main features of the tool holder are

  • It accepts all 1/2-inch tall P-type blades, mounted upside down.
  • The bottom of the slot is on the exact centerline of my particular lathe. This allows the tool to be extended however far I need while still remaining at centerline. Canted designs do not do this. The Sherline OEM tool holder may not be on the centerline either so a shop-made one is a better option.
  • There is a ledge on the bottom of the tool holder that automatically aligns the tool perpendicular to the work. A single screw locks the tool to the carriage in a few seconds. The ledge eliminates the possibility of movement, even under very heavy loads.

Inverting the parting tool does several things

  • Improves geometry. Instead of being a zero-rake cutter an inverted tool has back rake, which assumes the importance of side rake on a turning tool. This not only reduces cutting forces but also greatly improves chip ejection from the cut and thereby also reduces cutting temperatures. Furthermore, the 5-degree side rake on a P-type tool also narrows the chip, improving chip ejection even more.
  • Improved oiling. On an upright parting tool the chips are piling up on top of the blade and carry much of the cutting fluid away before it even gets to the tip. With an inverted tool the oil gets to the tip first, further reducing cutting temperatures and improving both accuracy and finishes because the cut is no longer dry.

So, you have greatly increased rigidity, reduced cutting forces and cutting temperatures, improved oiling, and the ability to cut at higher speeds that leads to improved accuracy and finishes. With all of this I cannot imagine why a guy wouldn’t rear-mount a parting tool!

I also believe the improved geometry allows a blade to cut a larger work piece than expected. A P1N blade is usually used for work up to 3/4-inch OD but I use mine on work up to 1-1/2-inch OD, double what you would expect to be able to cut. I do alter the angle at the nose of the tool; I use 7 degrees instead of 5 or 10. I have found edge life to be greatly improved, while still clearing chips easily.

Here is an example of a cut made in 12L14 mild steel. The OD is 1-1/4-inch at the cut. Depth of the grooving cut is 5/16-inch and I made two cuts side by side to allow my turning tool to fit in there. Speed is 1200 RPM and I purposely extended the blade about 5 times more than needed for this depth of cut to see if I could induce chatter – there was none – note the finish inside the groove. This part was later parted off about an inch from the chuck at the same speed and came off cleanly. I assure you that I cut like this all the time, in all sorts of materials.I set cutting speeds based on how the feed feels. The tool should cut freely and easily but allow me to feel the tip in contact with the work while feeding at a pace I can keep up with comfortably. Because the tool cuts so well there is little fear of digging in or chattering so speeds and feeds are much higher than you would expect. Continue reading Rear-mounted Parting Tool Holder for Sherline Lathe

Random Quote

One person with courage makes a majority.

— Andrew Jackson