Busch precision 24" camel back cast iron straight edge

[Richard King]

Hi,

Thought I'd post this as part of the scraping of my friend' camelback, but since Rich mentioned the procedure for "stress relieving" the casting, here's my effort http://www.youtube.com/watch?v=oaelbt3VO8s&feature=youtu.be

Just so everyone knows....I call that wringing the straight-edge. I learned that technique from my Dad when I was a very young man when we made our own S-edges. Even when the S-Edge is old and your re-scraping it, it's a good idea to do that. I generally don't hit them that hard, but it was a very musical bell ringing Jan. LOL... I usually use a dead blow hammer (lead covered with plastic) or a chunk of wood and I tap the S-Edge all over especially the camelback ridge top to bottom and I also tap on the scraped surface about 1/2 that hard. It just gets the iron moving or vibrating. We have found over the years that if you don't do that the S-edge has a tendency to change a bit during use as you bump it so gently when using it. When I scrape a Jig bore or something super precision I will wrap where I pick it up with rags and duct tape it so the heat of my hands doesn't affect the temp of the iron. I do the same thing with the level and King-Way. Another thing to keep in mind is the surrounding temp. The Moore book says 68 F is ideal. It should be a constant temp, not a cold shop at night and then turn up the heat in the morning, as this will change the different thicknesses of the metal and warp the flatness. Keep the S-edge and machine out of direct sunlight as this will affect the accuracy. When you drop a S-edge (everyone will sooner or later) be sure to wring it before and during the re-scraping. You know Jan, next Christmas maybe make a set of S-edge bells and play us a tune....lol...just kidding my friend. I love your You-Tube video's and your famous as I am sharing them with the other forums I write in. :goodjob:
I see you have 42..wowwwww...I have only watched the ones you posted here...One of these days I'll watch them all
Keep up the great work. Rich

 

[DaveSohlstrom]

I bought one of the Greg Dermer 18" camalback castings. They have been heat treated and machine like butter. No flaws.

Dave

 

[COMachinist]

I bought one of the Greg Dermer 18" camalback castings. They have been heat treated and machine like butter. No flaws.

Dave

HI
Well I didn't win the bid on the 24"Busch so it looks like it will be one of Greg's castings. Is the 18" useable on a small table top mill, or should I go for the 36". My surface plate is only 24x24. What say yee?
CH

 

[Richard King]

HI
Well I didn't win the bid on the 24"Busch so it looks like it will be one of Greg's castings. Is the 18" useable on a small table top mill, or should I go for the 36". My surface plate is only 24x24. What say yee?
CH

It is a pain to lap scrape a long straight edge on a short plate, so I would suggest buying 24" one. Plus it will be perfect for your machine. You may ask him how much he would charge you to machine it for you. Might be better on his machine then yours if it is worn.
The rule of thumb is always have a straight edge longer then your part. But if your part is 18" the best would be a 24" and not a 36".

Be sure to ask him about the heat treating. If he has heard of any movement after only one heat treating.

I would also paint it before you scrape it as your oily hands will absorb into the raw iron.

 

[COMachinist]

It is a pain to lap scrape a long straight edge on a short plate, so I would suggest buying 24" one. Plus it will be perfect for your machine. You may ask him how much he would charge you to machine it for you. Might be better on his machine then yours if it is worn.
The rule of thumb is always have a straight edge longer then your part. But if your part is 18" the best would be a 24" and not a 36".

Be sure to ask him about the heat treating. If he has heard of any movement after only one heat treating.

I would also paint it before you scrape it as your oily hands will absorb into the raw iron.

Hi Rich you kind of lost me here in the fog of war. He does not make a 24" straight edge, just 18" and 36" camel backs. He no longer heat treats them which is ok with me I'll just put in the electric furnace which is PID controlled, and take care of that myself. I have a 24"X24" surface plate but I was thinking that a 36" straight edge on a 24" surface plate may be a problem. The table on the little mill is only 26" on the ways. I'll ask him about the machining when he calls me back with the price and shipping. If it is to much I'll just through it on the Bridgeport and do it myself.
Thanks
CH

 

[Erik Brewster]

I know it sounds like sacrilege, but a 36" can become a 24" (or any other smaller number) with just a hacksaw. You have to stress relieve it and machine it, anyway.

 

[COMachinist]

I know it sounds like sacrilege, but a 36" can become a 24" (or any other smaller number) with just a hacksaw. You have to stress relieve it and machine it, anyway.

Hi Eric
Yep been thinking that myself. I think the 36" is the way to go and make 12" for small parts or short compound slide ways. I plan to CNC my G0602 lathe which will need to be scraped in before the conversion as well. He has a 36" now for under 200.00
CH:thumbsup:

 

[Richard King]

I would never do that. The camel-back is designed to combat twist and movement with the entire length . You go and cut it off one end and you have something that's an odd ball and you loose the stability. I know you like to save money, but cutting off an end of a straight-edge seems silly to me. Rich in the UK cut off both ends and made it look OK. But someday you might want a 3' straight edge and you'll kick yourself in the butt for doing that. Plus if you ever decide to sell it...who would buy it besides Erik? If you have a 18" table, either buy a 18" straight-edge or a 24". It's your money, do what you want, but as your advisor i would say don't do it.. Another thing you should get them stress relieve 2 times as I said before, or it will move on you. Rich

 

[Uglydog]

Daryl I posted his name and Greg's who both sell them in "Tools to Buy" forum: Here is what I said.

Re: What tools to buy?

I wouldn't count on machine repair guy.

Contact these guys, they makes them and they are legit. Both of the following 2 guys I believe sell them raw casting, machined or scraped.

Gregory Dermer ....... Greg was a student and I know a friend of mine just bough a couple castings from him a month ago
2945 NE 17th Ave
Portland, OR 97212

503-805-0680

Also this guy used to make em too. The last time I spoke to his guy 2 years ago and he was out of stock.....

Craig Donges, 8389 State Route 534, Berlin Center, Ohio 44401. Tele. # : 330 502 0066.

There is also a Indian company I have been talking to who makes them. Try those guys and if you don't get results let me know and I'll contact the other company.

Please let me know what you find out from these guys.

I know Polor Tool in Mpls has some used ones but he has unrealistic prices.

When I buy Dura-Bar I order grey iron. I believe it's class 25. The Dura-Bar plant I order from is in Wood-Stock IL

Also expect to high heat stress relieve the castings. Ask Greg and Craig if hey have been stress relieved. I would high temp stress relieve them before machining then stress relieve them again and then finish machine and scrape them.
High temp stress relieve means "cooking" the iron over 12 hours time. Put them in a furnace and take the heat to 1100 for 2 hours, then lower the heat to 900 for 2 hours, then lower to 700 for 2 hours, then 500 for 2 hours, then 250 for 2 hours and then off till they get to room temp. I have pro's do it.
Heating it up and shutting of the heat does nothing. If you don't stress relieve it will move around a lot. You will scrape it and the next day it will change.
Also "wring" the straight edge and that means to hang it from a rope and hit it with a soft blow hammer or 2 x 4 and let the iron vibrate or wring like a bell

Rich
​

I'm watching this thread closely.

Rich, thank you for your clear no-nonsense guidance and expertise. I'm slowly making forward progress toward scraping. Thanks to Senna, I now have a gorgeous 66inch x 30inch inspection plate. She is only 4 inches thick, but at $140 delivered, with a stand, she is a real blessing for which I am grateful to Senna. I'm making an aluminum protective edge and am taking a few hours today to wire brush the stand and paint. She is certainly not a AA or even an A. But, I believe she will meet my initial needs quite well.

Picked up a used hand Anderson hand scraper a month ago, and am casually looking for an 18inch or 24inch.

Thank you all for the thread.
And, thanks again to Senna for watching out for me!

Daryl
MN

 

[loply]

Regarding cutting a straight edge down from 36" to 24".

I recently did exactly this. I would start by pointing out that I had no choice; I searched for months to find a straight edge with a knife edge in the UK, and never found a single 24" one for sale either new or used. Emailed a few foreign companies but no helpful responses. Even contacted a local foundry but they weren't interested in helping.

In the end I found a used 36" one and reluctantly bought it knowing it was too big. As it turns out, it was warped a little bit out of shape anyway, despite being made in England and from the 1970s, so I didn't feel too guilty about cutting the ends off it.

It looks good still, and my analysis is that the overall new shape/structure is still suitable. Whether it will move in future I can't say, but, now that it is 24" and fits on my surface plate, if it does move I'll just scrape it again!

Anyway, my only advice to you if you want to do this is that you'll need a good saw... I used an automatic bandsaw. I wouldn't try it with a hacksaw or a grinder unless you've got lots of patience.

But I would try to find a 24" one first, I wouldn't have gone to the effort of doing this if I had any other choice.

Cheers,
Rich