Fortunately, I'm only in business to design/manufacture parts for myself. If I were to factor in the time I dedicate to this venture in the $$ equation, I'd have quit before I started!
Fortunately, I'm only in business to design/manufacture parts for myself. If I were to factor in the time I dedicate to this venture in the $$ equation, I'd have quit before I started!
That being said, go for it.
I think I mentioned earlier, I no longer take in outside work for my machine. I manufacture a line of running gear for gas powered remote control boats and trucks. I charge a lot of money for my running gear so if you don't buy it, that's OK. Usually I'll make 50 pieces. at a time and that will take me a couple of years to sell.
I'm 73 years old now and I don't do this to make a lot of money any more. I do it for something to do in my retirement years.
Steve, can you give a link to a web site with your stuff or share a few pictures?
Looks good. I am always amazed at some of the things people sell that you would think there is not much of a market for. And that comes from somebody that makes a good part of their living on making things that you would think there is not much of a market for.
Do you do the propellers also? Looks like they could be easily made, but the engineering behind designing one to be efficient would be significant.
You can buy GOOD PARTS or you can buy CHEAP PARTS, but you can't buy GOOD CHEAP PARTS.
I've read this thread with a fair bit of interest because I've been considering something similar.
Here is how I think these could be made for around $3.50 each, assuming you value your time at $60 / hr and allowing $5 / hr for machine operating costs but not amortizing machine and fixture costs and assuming no finishing (anodizing, etc). What I don't know is if the Tormach is accurate and reliable enough to make these parts to your requirements in this fashion. I also don't know much about rotary broaching but I'll assuming it can be done in the mill spindle and loaded from the ATC.
Purchase 1.25" 6061-T6 round bar, cut to approximate length with woodworking miter saw (carbide blade, use a stop to set length). A 6' bar is $50 at McMaster-Carr which is probably one of the most expensive places to purchase material. Assume $1.25 per part for material cost and $0.25 per part to cut to length (time actually cutting is likely under 5 seconds). This is 1h15 on the weekend to prepare the 300 parts you'll run during the week.
The key to making these cheap in your own shop is fixturing which allows you to load and run many parts at once in the minimum number of setups. I'm thinking 32 op1 parts and 32 op2 parts per cycle with the parts arranged as a line of 8 op1 parts and a line of 8 op2 parts on each side of a 4th axis tombstone. Each morning before going to your day job, remove 8 op2 (finished) parts from the 0 degree side of the tombstone, move 8 op1 parts to the op2 position and load 8 saw cut blanks. Index the rotary 90 degrees and repeat for the remaining 3 sides. Hit cycle start and go to the office. When you get home in the evening there is another 32 finished parts waiting for you. Take a few extra minutes, clean the chips out of the machine and start the overnight cycle. I think the part loading / unloading could be done in 20 to 25 minutes per cycle, add 10 minutes to remove chips from the enclosure every 2nd cycle and you're at $1.00 per part labour. Further assume the above estimate of 5 to 6 parts per hour machining time is accurate and that is another $1.00 per part in machine operating expense.
The tombstone is approximately 4 to 5" square and 18 to 20" long with 4 identical sides. Considering only 1 side of the tombstone, there is a row of 8 1.25" circularly interpolated semi circles at Y0.85. This is your fixed soft jaw for op1. Between pairs of semi-circles there is a tapped hole from the Y- direction to tighten a block with a matching pair of semi-circular cuts that acts as your movable jaw. Each pair of blanks has their own movable jaw. Op1 consists of circularly interpolating the bottom side features and thread milling. Op1 is strictly a 3 axis operation.
There are a similar row of semi-circles cut at Y-.85 but they are thread milled to accept the op2 parts. The op2 movable jaws are also thread milled. I would clamp shims, thread mill the fixed and movable jaws at the same time and keep them as matched sets. Use springs to spread the jaws so you're never fighting with a closed jaw when you're loading a part. Completed op1 parts are threaded into the op2 soft jaws and the screw tightened to clamp a pair of parts (to prevent unscrewing due to cutter forces). Op2 consists of milling top side features. The A axis is rotated slightly off 0 to mill the tapered sides and to 90 degrees to drill the 2 cross holes. The hex is also broached from A0.
Index the A90 and run the same code to mill the parts on the second side of the tombstone, etc. Run all your production parts like this during the week. Remove the tailstock and tombstone to run prototypes / other small volume parts in a vice on the weekend if required. If you're frequently running parts in a vice and don't need 1000 pieces per month, make the tombstone 9 or 10" long and put a vice on the other end of the table. I'm guessing you would be into this setup for $25k to 28k (1100, ATC, 4th axis, enclosure, etc) plus a month of weekends to assemble the mill, design and manufacture the tombstone / tailstock, etc. With this approach the larger travels of the 1100 are much more beneficial than the faster spindle / cycle time offered by the 770.
Please feel free to poke holes in this approach. I think the biggest question is the Tormach, is it reliable enough to run 6 to 7 hour cycles unattended and does it have the accuracy and rigidity to make these parts to spec (+/-.005 and 32Ra), while cutting 3"+ off the centerline of the 4th axis. I have tons of design experience but all my parts are made by someone else on industrial machines. I have yet to see a Tormach (or similar) cutting anything in person.
A 12 foot bar of 6061 extruded aluminum from Fry Steel would be in the neighborhood of $36.00 plus shipping.
I do a lot of cutting on a 10 inch Craftsman chop saw with a 40 tooth carbide tooth blade and a spray can of WD 40.
You can buy GOOD PARTS or you can buy CHEAP PARTS, but you can't buy GOOD CHEAP PARTS.
Really nice hypothetical simulation.
I have an 1100 with atc and 4th axis.
I really like the machine and support that comes with owning a tormach but there is no way in hell I would run it without being close by. Then again, I would not run any vmc without being close by just in case.
I have owned my machine for 3+ years but have never been able to get the atc to work flawlessly. I will have a month or so where it seems to work great then there is a crash (mechanical or electrical glitch).
It is my main struggle in dependability and I am hopeful to get everything ironed out so that I feel confident with it.
When everything is running well it is a great thing.
QUOTE=jgraves;2105410]I've read this thread with a fair bit of interest because I've been considering something similar.
Here is how I think these could be made for around $3.50 each, assuming you value your time at $60 / hr and allowing $5 / hr for machine operating costs but not amortizing machine and fixture costs and assuming no finishing (anodizing, etc). What I don't know is if the Tormach is accurate and reliable enough to make these parts to your requirements in this fashion. I also don't know much about rotary broaching but I'll assuming it can be done in the mill spindle and loaded from the ATC.
Purchase 1.25" 6061-T6 round bar, cut to approximate length with woodworking miter saw (carbide blade, use a stop to set length). A 6' bar is $50 at McMaster-Carr which is probably one of the most expensive places to purchase material. Assume $1.25 per part for material cost and $0.25 per part to cut to length (time actually cutting is likely under 5 seconds). This is 1h15 on the weekend to prepare the 300 parts you'll run during the week.
The key to making these cheap in your own shop is fixturing which allows you to load and run many parts at once in the minimum number of setups. I'm thinking 32 op1 parts and 32 op2 parts per cycle with the parts arranged as a line of 8 op1 parts and a line of 8 op2 parts on each side of a 4th axis tombstone. Each morning before going to your day job, remove 8 op2 (finished) parts from the 0 degree side of the tombstone, move 8 op1 parts to the op2 position and load 8 saw cut blanks. Index the rotary 90 degrees and repeat for the remaining 3 sides. Hit cycle start and go to the office. When you get home in the evening there is another 32 finished parts waiting for you. Take a few extra minutes, clean the chips out of the machine and start the overnight cycle. I think the part loading / unloading could be done in 20 to 25 minutes per cycle, add 10 minutes to remove chips from the enclosure every 2nd cycle and you're at $1.00 per part labour. Further assume the above estimate of 5 to 6 parts per hour machining time is accurate and that is another $1.00 per part in machine operating expense.
The tombstone is approximately 4 to 5" square and 18 to 20" long with 4 identical sides. Considering only 1 side of the tombstone, there is a row of 8 1.25" circularly interpolated semi circles at Y0.85. This is your fixed soft jaw for op1. Between pairs of semi-circles there is a tapped hole from the Y- direction to tighten a block with a matching pair of semi-circular cuts that acts as your movable jaw. Each pair of blanks has their own movable jaw. Op1 consists of circularly interpolating the bottom side features and thread milling. Op1 is strictly a 3 axis operation.
There are a similar row of semi-circles cut at Y-.85 but they are thread milled to accept the op2 parts. The op2 movable jaws are also thread milled. I would clamp shims, thread mill the fixed and movable jaws at the same time and keep them as matched sets. Use springs to spread the jaws so you're never fighting with a closed jaw when you're loading a part. Completed op1 parts are threaded into the op2 soft jaws and the screw tightened to clamp a pair of parts (to prevent unscrewing due to cutter forces). Op2 consists of milling top side features. The A axis is rotated slightly off 0 to mill the tapered sides and to 90 degrees to drill the 2 cross holes. The hex is also broached from A0.
Index the A90 and run the same code to mill the parts on the second side of the tombstone, etc. Run all your production parts like this during the week. Remove the tailstock and tombstone to run prototypes / other small volume parts in a vice on the weekend if required. If you're frequently running parts in a vice and don't need 1000 pieces per month, make the tombstone 9 or 10" long and put a vice on the other end of the table. I'm guessing you would be into this setup for $25k to 28k (1100, ATC, 4th axis, enclosure, etc) plus a month of weekends to assemble the mill, design and manufacture the tombstone / tailstock, etc. With this approach the larger travels of the 1100 are much more beneficial than the faster spindle / cycle time offered by the 770.
Please feel free to poke holes in this approach. I think the biggest question is the Tormach, is it reliable enough to run 6 to 7 hour cycles unattended and does it have the accuracy and rigidity to make these parts to spec (+/-.005 and 32Ra), while cutting 3"+ off the centerline of the 4th axis. I have tons of design experience but all my parts are made by someone else on industrial machines. I have yet to see a Tormach (or similar) cutting anything in person.[/QUOTE]
Thanks for bringing your experience to the discussion.
In my opinion, half the value of CNC is pressing cycle start and walking away (with proven code, the other half is the ease of cutting complex geometry and improved speed over manual). The only way I would consider running small volume production myself is with run long cycle times (many parts at once or large high value parts) with minimized part handling.
I've been following the Tormach since shortly after the 1100 was introduced and I'm close to purchasing something. Until I really started researching seriously a couple months ago, I just assumed "something" would be an 1100 when the timing was right. Now I'm not certain. There are much better machines for the money but the Tormach is the only machine I'm seriously considering at this price point, due to the on-line community and the general consensus that factory support is also excellent. The next step up with similar support seems to be Haas at double or more the cost.
I'd be hugely disappointed in my purchase if I couldn't press cycle start, go into the house and sleep soundly all night while the machine ran a 10+ hour cycle and dozens of tool changes, even if I was only ever making parts as a hobby. I'd be equally disappointed if my "much better" machine was down for months while waiting for a repair part on a slow boat from Taiwan, China or India or trying to troubleshoot an issue with no on-line community and poorly translated documentation.
I've drifted a bit off topic with more of a "can a Tormach be an acceptable substitute for a VMC for me?" flavor so I'll try to get back to bringing the OP some value in my next post.
As a former Haas owner, I can tell you first hand, I can do anything on my Tormach 1100 that I could do on my Haas. It just takes a little longer. And ya know what else? My Tormach with 30 TTS Tool Holders, 8 inch 4th axis, power draw bar, foot pedal and full enclosure was less than $20,000.00. My Haas was a little over $35,000.00 without the full enclosure. AND I can do plus/minus .00075 work on it, all day long.
"I'd be hugely disappointed in my purchase if I couldn't press cycle start, go into the house and sleep soundly all night while the machine ran a 10+ hour cycle and dozens of tool changes."
It takes a commercial VMC to get that degree of reliability - I would like to hear from anyone running a Tormach that actually regularly does that.
"In my opinion, half the value of CNC is pressing cycle start and walking away (with proven code, the other half is the ease of cutting complex geometry and improved speed over manual). The only way I would consider running small volume production myself is with run long cycle times (many parts at once or large high value parts) with minimized part handling."
If it is a Tormach...walking away yes...but not too far!
Cheers Cliff
I've modeled the 4th axis fixture concept I attempted to describe in my earlier post, cut from 6" diameter round bar. The attached screen shot plus a couple google image searches for "4th axis tombstone" and "4th axis trunnion" should be a good start to designing this for real. I'll also share the step file if you PM me with a request and e-mail address but it is a complete BS conceptual model.
Steve,
Do you have an ATC on your Tormach or did you have one on the Haas? Which model(s) Haas did you have and what vintage? I'm assuming a TM or MM based on no enclosure. How does the reliability of the Tormach compare to the Haas in your experience? Is the surface finish comparable? What type of parts did you make on the Haas (size, materials, tolerances, 2.5D or 3D surfaced)?
I've been considering everything from a loaded 1100 with diy stand / enclosure / coolant through the TM-2P and VF-2 to the VM-2. I want a well equipped single phase VM-2 with Tormach price tag I'm still trying to decide which is the right compromise.
mike sr
Yes I am waiting to see if any Tormach operator has ever run his machine all night.... while he slept soundly.....maybe?
I would have to take serious sleeping meds to do that! Cliff
When the stars are aligned and everything seems to be working, I occasionally go inside and have dinner whije the machine is running. Some times I have come back to an atc crash, though.
I have also had my Tormach machine through the night several times but it was with no tool changes, just one tool doing a big 3D part.
I think you will need to spend in the $100k plus range to get what you are looking for.
The tormach is a great first machine or hobby machine and it has allowed me to learn and make parts. If I ever feel like I can get the atc to work reliably, I actually think about adding another one to my shop. I will probably get a different/bigger machine to add instead.
QUOTE=keen;2105860]Yes I am waiting to see if any Tormach operator has ever run his machine all night.... while he slept soundly.....maybe?
I would have to take serious sleeping meds to do that! Cliff[/QUOTE]