Some time back I had a customer ask me for some large head shoulder bolts for clamping screws for his molds. I didn't really want to make them, but when I shopped around I couldn't find anything that fit the bill. I did find a plastic head one, but since plastisol is kicked at 350F degrees and is sometimes injected hotter. Also sometimes guys preheat molds on a hot plate. I wasn't really crazy about that idea, and I wanted something that could be used for lead casting molds too if I was going to make and stock it.
I found the easiest way to make them was to make an aluminum knob with a knurled head and a shoulder below, then drill, counter bore and tap the knob. This made it easy for me to run in a stainless socket head screw of whatever length was suitable for the particular mold. Its somewhat time consuming to make a batch of them, but I setup a small tailstock turret on one of my smaller lathes for drilling, counter boring and tapping the two most common sizes I use in molds. The tools all stay in the turret all the time. I rough, knurl, and part the knobs on one machine then shove the shoulder in a collet on another to drill, counterbore and tap. Its not fast, but its the most efficeint method I could figure out without going to a CNC lathe with gang toolng or turret type tool post (or both). t takes me several minutes per unit at best. I figure a good CNC setup or screw machine could crank them out in half a minute per part or faster.
Back to the original project. I gave the customer a price and a bulk price that would cover my time. I figured he would baulk at the price and that would be the end of it. Nope. He bought 25 of them.
As time has passed I've sold a few off of my website. They are expensive, but the feedback I have received has been overwhelmingly positive in regards to safety and productivity of having a toolless clamping screw they can grip with a glove on. Well for those who have bought them. I have received some negative comments on social media. Mostly about price.
I also make a few other products not directly related to mold making. I'm in the process of developing a couple right now. Nothing new or original. Just product improvements on old ideas. One I wanted to update a little and use knobs / shoulder bolts. Make it a little faster without having to hunt for a wrench or a hex key. I didn't really want to make more knobs and shoulder bolt knobs, so I started shopping for something that would fit my design or that I could modify my design to make use of. There are some potential knobs and shoulder bolts out there but they are kind of expensive. My price is actually in line with small quantity vendors, and none were exactly what I wanted.
Now I could probably contact a screw machine shop or post an RFQ on one of the machining sites and get a decent per unit price on exactly what I want if I purchased 10K units at a time. Since the product will take three different clamping screws and I figure I'd probably only sell a couple dozen a year at best. More likely a handful. That's just to much outlay upfront. I might not live long enough to take advantage of the savings. So... for small quantities its cheaper to (figuratively speaking) buy them from myself. If I "pay myself" to make them at the same rate I charge a customer to make them for them I make a few sheckles off the knob as part of the other product.
Now for those negative nellies who always read a post like this for the purpose of finding something to be crummy about... bug off. I'm neither bragging nor asking for help. I posted this as a maybe bit of help or push for people who are always looking for something to make and sell. Its not worth it for you to make one (1) knob for anybody, but if you find somebody who needs small quantities and you can make 10-20 at a time you can pay yourself a fair wage for standing in front of your lathe. If they suddenly want a bunch you can always post an RFQ for a screw machine or CNC lathe shop. I don't mean to say you should go out and make knobs or shoulder bolts persay, but there are low to medium demand products that you can make and sell that will atleast pay for the material for your own projects. Stuff that retails high enough after distribution that it costs more than you think it should. You could price match retail, and make a product that more exactly meets somebody's needs. Many of these things (like aluminum or even steel knobs / shoulder bolts) don't require any more tolerance than you can easily produce on a cheap import machine.
I found the easiest way to make them was to make an aluminum knob with a knurled head and a shoulder below, then drill, counter bore and tap the knob. This made it easy for me to run in a stainless socket head screw of whatever length was suitable for the particular mold. Its somewhat time consuming to make a batch of them, but I setup a small tailstock turret on one of my smaller lathes for drilling, counter boring and tapping the two most common sizes I use in molds. The tools all stay in the turret all the time. I rough, knurl, and part the knobs on one machine then shove the shoulder in a collet on another to drill, counterbore and tap. Its not fast, but its the most efficeint method I could figure out without going to a CNC lathe with gang toolng or turret type tool post (or both). t takes me several minutes per unit at best. I figure a good CNC setup or screw machine could crank them out in half a minute per part or faster.
Back to the original project. I gave the customer a price and a bulk price that would cover my time. I figured he would baulk at the price and that would be the end of it. Nope. He bought 25 of them.
As time has passed I've sold a few off of my website. They are expensive, but the feedback I have received has been overwhelmingly positive in regards to safety and productivity of having a toolless clamping screw they can grip with a glove on. Well for those who have bought them. I have received some negative comments on social media. Mostly about price.
I also make a few other products not directly related to mold making. I'm in the process of developing a couple right now. Nothing new or original. Just product improvements on old ideas. One I wanted to update a little and use knobs / shoulder bolts. Make it a little faster without having to hunt for a wrench or a hex key. I didn't really want to make more knobs and shoulder bolt knobs, so I started shopping for something that would fit my design or that I could modify my design to make use of. There are some potential knobs and shoulder bolts out there but they are kind of expensive. My price is actually in line with small quantity vendors, and none were exactly what I wanted.
Now I could probably contact a screw machine shop or post an RFQ on one of the machining sites and get a decent per unit price on exactly what I want if I purchased 10K units at a time. Since the product will take three different clamping screws and I figure I'd probably only sell a couple dozen a year at best. More likely a handful. That's just to much outlay upfront. I might not live long enough to take advantage of the savings. So... for small quantities its cheaper to (figuratively speaking) buy them from myself. If I "pay myself" to make them at the same rate I charge a customer to make them for them I make a few sheckles off the knob as part of the other product.
Now for those negative nellies who always read a post like this for the purpose of finding something to be crummy about... bug off. I'm neither bragging nor asking for help. I posted this as a maybe bit of help or push for people who are always looking for something to make and sell. Its not worth it for you to make one (1) knob for anybody, but if you find somebody who needs small quantities and you can make 10-20 at a time you can pay yourself a fair wage for standing in front of your lathe. If they suddenly want a bunch you can always post an RFQ for a screw machine or CNC lathe shop. I don't mean to say you should go out and make knobs or shoulder bolts persay, but there are low to medium demand products that you can make and sell that will atleast pay for the material for your own projects. Stuff that retails high enough after distribution that it costs more than you think it should. You could price match retail, and make a product that more exactly meets somebody's needs. Many of these things (like aluminum or even steel knobs / shoulder bolts) don't require any more tolerance than you can easily produce on a cheap import machine.
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