Recommendation? A few questions from a beginner

[HWooldridge]

Here’s a short bio for the purposes of introduction plus a few questions. I’ve been a member of this forum for just over a year and a daily lurker; have read a lot and posted a few times. I’m 59 years young and got interested in blacksmithing in my mid-twenties; was fortunate enough to obtain a wide range of equipment when it was easier to find and built a couple of nice shops over the years. I always worked fulltime during the day and part time in my shop for the last 35 years or so. I created a website in 2002 to sell custom ironwork but finally took it down 4 years ago because 40-50 hours at the day job and another 30-40 in the shop made for a burn-out situation (I also bale hay during season for myself and my neighbors).

To make a long story short, I have a well equipped shop aimed at machining, blacksmithing and ornamental ironwork. Multiple solid fuel and gas forges, anvils, fly press, power and treadle hammers, couple lathes, vertical mill, crank shaper, hydraulic press, etc. - & the necessary hand tools. I know how to forge but never had much interest in knife making. Several years ago, one of my sons got into hog hunting with dogs and knives (he is now a ranch foreman who also guides hunters for a variety of game animals). The two of us developed a knife design specifically for hog killing (I know you can use most any long blade but this has a couple of tweaks). My son thinks I should make these for the hog hunting market and believes he can sell some to his clients. It’s no great revelation, basically just a stiff 11” blade with single bevel cutting edge and chisel-point; a robust ring hilt and contoured handle to allow the user to control the blade without losing hold in a fracas. It’s also “handed” and is built to the hunter’s strong side. My son has probably killed over two hundred hogs with his version and he carries it every day while working.

Therefore, I am slowly accumulating tools to assist the process. I built a 2x72 belt grinder about 25 years ago from scrap-yard parts and it is a beast (220v, 2hp motor) but I only ever used it for deburring stock with a 10” contact wheel made from a caster. I recently bought a flat platen attachment from Oregon Blade and have been experimenting with that setup but the grinder does not have variable speed control. I also bought some Aldo 1075 and plan to stick with basic carbon steel – no stainless or other alloys for now. We want to build some nice working blades that will perform well under stressful conditions.

Here are my questions:

1. I think a good VFD is the next thing to add to the grinder – does anyone have a favorite brand or one that is commonly used by OEM’s?

2. I was considering building some salt baths for hardening/tempering in order to help with process control but I’m thinking that is overkill at this point if I’m using 1075. I do have a large kiln with a good quality digital pyrometer and I can wrap each blade in SS foil to help with decarb. Any thoughts on a best method?

3. The design builds better with a hidden tang but I’m worried about how robust epoxy will be over the long haul. I expect these knives will get tossed in the back of pickup trucks or ATV’s, stomped on, etc. I glued and put one pin in my son’s knife and it has held up over time – he’s really rough on things so I figure it’s been a good test but was wondering if anyone has an opinion one way or the other?

4. Finally, we are going to use stag for handles since we have a ready supply of drop tines. Should I plan to stabilize antler? I have a nice vacuum setup left over from a lost wax casting project but have never done any stabilization.


Thanks in advance, HW

 

[Busto]

You have a lot going on....

1. KBAC-27D used by most OEM grinder manufacturers I use them for mine. NEMA sealed so no worry about dust or moisture. There are cheaper imports available that generally require you build an enclosure to keep dust out.

2. Simple carbon steel at low austenizing heat treat temps in a kiln will get scale however it's overkill to wrap with stainless foil since soak time and higher temps usually reserved for stainless blades are not reached....save some money.

3. If you plan to build hard use equipment with any type warranty build it like a tank or expect headaches on return warranty work. Full tang knives with scales should be attached with Corby Bolts and epoxy. Hidden partial tang use Good Epoxy and minimum 0.125 peened pin.

4. Stag looks good but refer to #3 above.

 

[DAMNENG]

HW
First, welcome to the forum.
1. I've been using a TECO Westinghouse VFD for about 20 years with no problems. There are many different VFDs on the market with a great variety of options. Many companies making VFDs offer them with the option of using single phase 220V or three phase input up to 3hp. Over 3hp I don't think there are any that don't require 3 phase input. One feature I enjoy is a programmablr ramp up and ramp down speeds. I have mine set on for 3 seconds on ramp up. This gives me time to adjust tracking before the belt is running at screaming speeds. So check what features are available on the VFD you choose before you buy.

2. I agree with Busto, 1075 heat treat using a forge is no problem.

3. I would agree that full tang is more robust than hidden tang. If done properly hidden tang will work. I suggest two pins and use a good epoxy such as System Three or West System. USE the slow cure epoxys! Its Kinda liken concret, slower the cure the stronger.
I don't guarantee grips, but I do replace them on my knives at a very reasonable rate. If you want durability, go with Micarta.

4. As far as the durability of antler goes, I suggest you build a couple of test knives, one with a tler and one with stabilizedmantler and abuse the crap out of them. This will tell you if the grips, and if your blades will survive abuse.

Enjoy!
Jim A



2

 

[AndrewC]

1. I bought the KBAC-24D and love it. For 2hp you'd need the -27D Busto mentioned. I assume it's a 3-phase, as single-phase induction motors don't do VFD / variable-speed. I absolutely recommend one with a KNOB speed control vs. up/down buttons, digital, etc. (DAMNENG mentioned a programmable 3-second ramp-up -- I'd much rather just turn mine to a creep, adjust the tracking, and then bring it up with the knob. Much more intuitive and responsive than punching membrane buttons....)

2) Salt bath setup is WAY overkill, and quite a lot of work, expense, and "stuff that if it goes wrong goes badly wrong".... I have a programmable lab furnace leftover from my old company; works great, no issues. I paint on ATP-641 from Brownells to prevent decarb - works great, a small can don't cost much and lasts forever.

3) I really, really like the 15-minute epoxy from BSI (Bob Smith Industries). Costs way less than G-flex from West Marine, and comes in more convenient quantities*. The 15-minute "Mid-Cure" is apparently the ideal for both flexibility and strength, vs. either shorter or longer cure times - and I find 15 minutes just right to get things set up, clamped, and adjusted. I always let it set & cure completely at least overnight; 24h preferable; before working.

As to pins: I make chef's knives only, and my feeling is that shear force is 95% of the concern with scales staying put. I don't think there's a lot of prying/pulling force that's likely to happen. So a couple of pins, even if they're not peened hard to pull the scales to the tang mechanically (ditto Corby bolts etc.) seem far more than sufficient to counteract shear/twisting force that'd manage to break the epoxy loose, 'specially if it's an epoxy with a bit of flex/give like both G-Flex and the BSI Mid-Cure. I see plenty of chef knife makers that put out full-tangs with no pins at all, so I figure I'm in good company - but would welcome (polite) disagreement.

*If you hunt around you can find a pack of 2 x 4.5oz bottles (9 oz total) rather than the 2 bottles equals 4.5 oz. that's standard -- confusing, I know -- for way less than 2x the cost. I just got a 9-oz-combined pack on Amazon for $15, vs. $10 for the 4.5-oz-combined price.

 

[HWooldridge]

Thanks for all of the replies. The grinder motor is an oddball that was salvaged from an old government hard drive setup we found in a scrapyard - it's 2850 rpm at 230v 1 ph and running a 4" drive sheave. If I did the math right, I should be getting almost 3,000 sfm. I do have a 3 phase converter for my big tools. I don't know much about VFD - the only motors I have that are speed controlled are brush type with rheostats. If I'm reading the replies correctly, it sounds like I need to obtain a 2-3 hp 3 ph motor.