Advice sought on making straight edges from Lathe bed

Looking for some advice / thoughts on to make some straight edges from two blanks taken from an scrapped antique lathe. Both are just over 30” and 5” deep and are typically as per the images and approximately
dimensioned as per these sketches.


Blank A is a little wider at the base and the dovetail is currently 55° I thought this would give me a bit more meat to machine it to 45 °. The large rib along the top does not continue the full length.

I do not yet have a surface plate and am looking at 24” x 18” as being the max I probably need or can fit in my workshop. I may be able to stress relieve by heat treatment.

Here are my thoughts

1. As I neither need nor will be able to check a 30” I cut the ends @ 65° as shown by the blue lines – that way losing the section where there is no stiffening rib.
   
2. The stiffening rib is substantial @ 1 x 0.7" and offset so perhaps I can machine some of it away to lose weight.
   
3. Machine away the other bosses and clean up the vertical ribs
   
4. The vertical ribs will not be centred along the length so if no one says otherwise I’ll put a couple of lightening holes equidistant between them as per the sketch.
6. Perhaps for the other blank I could make an 18” and a 12”?

Am I correct in thinking that it will be easier for me to learn to scrape in the 12” first ?
I appreciate that these will never be Kingway camelbacks, but I have seen Youtubers make some nice straight edges from a similar starting point.

This is very interesting and quite challenging project. My personal opinion is you keep those edges for when you have some specific need - like you need to make a custom tool. When you try to learn it is best not to fight too many problems in the same time. It is best in my personal opinion that you purchase a good surface plate ( maybe even a Granite one ) and a factory made straight edge. Then you develop your skill in scraping and later you can tackle more difficult projects. I can suggest you get a couple of 6" Durabar disks around 1/2" or less thick and practice on them. In that way you do not fight too many challenges, no stress and you need only very small surface plate which could be 8" or so which you can have ground or lapped . This is good enough just for practice in the very begining.

Well its worth a try especially to learn to scrape.
For what its worth - I would get the biggest surface plate you can fit/afford - I got a 18x24 and its too small for a lot of the machine parts I have worked on - this just makes the task more difficult - the last thing you need when you start out.
In terms of first bit to practice on - I would chop the ends off as per your sketch and then have a few hours playing with them to get your muscles working. Maybe make yourself a short 48 degree edge - 8" long ?
Once you have machined your blank - stick it aside and leave it (hung if possible) for as long as you can - so that the stresses can equalize - check it by measuring some known points to see if it moves. You will chase your tail scraping if its moving as you scrape.

There are plenty of chaps on here that know more than I ever will - Im sure there will better advice added below.

If it were me, I would rough one into something like at 15ppi then leave it hanging while I rough out the second one - then re-check the first after a month or two to see whats changed.

Good luck
Mat

My dad made a healthy 18" straight edge out of a section of machine bed many years ago. He didn't stress relieve it and every time he would scrape on it, it would walk off into another direction. He finally gave up on it. After nearly 50 years of dragging it around everywhere we lived, I gave it away to a buddy of mine for a learner piece for a scraping project.

Plan on doing some kind of stress relieving on your straight edges once you have them whittled out to the shape you want.

Ken

Do you know if the ways may have been flame hardened? If so, scraping them may not be a lot of fun. If you cut the pieces with an abrasive disc, you can't tell. If you band sawed them and they cut nicely, then they will probably scrape OK. Proper thermal stress relief before you start, as previously suggested, would be important and could be done in a good-sized ceramics kiln. Taking a sharp file to the ways and to the rest of the casting may provide clues as to relative hardness. If the file cuts the way just like it cuts the rest of the casting, the way probably was not hardened.

Denis

A longtime PM member Jan Sverre Haugjord who also has several You Tube shows on scraping cut up a wood lathe bed in 2015 and documented it on You Tube. He sold them to some of the students of the Danish scraping school. So I think you will be fine. The cast iron is aged if it's antique...how old is your lathe? I hope you make a thread showing all what your doing or a You Tube show. Sounds like a good read and watch! Poor man's straight edges - YouTube

PS: 1/2 Norwegian and 1/2 English...lol

He also makes some from an old lathe he found at a farm. LOL
Making straightedges.. again - part 1 - YouTube

There are several good You Tube shows of making Straight edges. A bit OT but interesting from another PM member on You Tube. He has some great shows on scraping and many things machine shop too. From Germany - Stefan Gotteswinter
Part 1, and there is a part 2
Making a straight edge blank Part 1/2 - YouTube

I contemplated cutting the ways out of the big Czech turret lathe we scrapped, but decided against it given the incredible amount of iron I would need to saw/drill/torch through to get a functional 48" section (typical old soviet iron apparently). The professionally made castings available now are just too "cheap" to justify the labor on my part, and they look so much nicer!

Advice sought on making straight edges from lathe bed

Thanks for all of the input I'll try to respond in order.

keep those edges for when you have some specific need - like you need to make a custom tool. When you try to learn it is best not to fight too many problems in the same time. It is best in my personal opinion that you purchase a good surface plate ( maybe even a Granite one ) and a factory made straight edge. Then you develop your skill in scraping and later you can tackle more difficult projects. I can suggest you get a couple of 6" Durabar disks around 1/2" or less thick and practice on them. In that way you do not fight too many challenges, no stress and you need only very small surface plate which could be 8" or so which you can have ground or lapped . This is good enough just for practice in the very begining.

Click to expand...

I may well keep one edge blank as it is as I have the headstock end of the bed that will yield another two 12" blanks. I will practise on some other Durabar type material that I have. I am looking at a new granite surface plate as the prices of used cast iron ones do not seem to reflect their condition and the uncertainty around their flatness. A factory made edge is out of my price range right now.

I would get the biggest surface plate you can fit/afford - I got a 18x24 and its too small for a lot of the machine parts I have worked on - this just makes the task more difficult - the last thing you need when you start out.
In terms of first bit to practice on - I would chop the ends off as per your sketch and then have a few hours playing with them to get your muscles working. Maybe make yourself a short 48 degree edge - 8" long ?

Click to expand...

Well it's the same valid argument as buy the biggest lathe you can afford, ultimately space and budget have to be considered and I'm not planning to become a rebuilder. Please can you explain the choice of 48 degree's ?

Plan on doing some kind of stress relieving on your straight edges once you have them whittled out to the shape you want.

Click to expand...

Do you know if the ways may have been flame hardened? If so, scraping them may not be a lot of fun. If you cut the pieces with an abrasive disc, you can't tell. If you band sawed them and they cut nicely, then they will probably scrape OK. Proper thermal stress relief before you start, as previously suggested, would be important and could be done in a good-sized ceramics kiln. Taking a sharp file to the ways and to the rest of the casting may provide clues as to relative hardness. If the file cuts the way just like it cuts the rest of the casting, the way probably was not hardened.

Click to expand...

I am working on a heat treatment oven project with a friend - we are building one each and plan to make them such that they can be joined to accommodate larger pieces - failing that I know someone with a pottery kiln.


Yes I did cut them with a ("grinder with a diamond disc - it was much easier than expected. The ways are not hardened, I checked with a file this evening and an offcut machined really well.

A longtime PM member Jan Sverre Haugjord who also has several You Tube shows on scraping cut up a wood lathe bed in 2015 and documented it on You Tube. He sold them to some of the students of the Danish scraping school. So I think you will be fine. The cast iron is aged if it's antique...how old is your lathe? I hope you make a thread showing all what your doing or a You Tube show. Sounds like a good read and watch! Poor man's straight edges - YouTube

Click to expand...

Thanks Richard I have seen his work and noticed he has upgraded from those edges he made - nice to hear that they have been passed on rather than ditched due to issues. The lathe was at least 100yrs old. As it will be a while before I get a surface plate I plan to do the machining and stress relief in the meantime and I'll start a thread when I have a bit of a story to post otherwise there will be a flurry now and then nothing for a few months.

There are several good You Tube shows of making Straight edges. A bit OT but interesting from another PM member on You Tube. He has some great shows on scraping and many things machine shop too. From Germany - Stefan Gotteswinter

Click to expand...

Yes I am fan of Stefans work, it was his heat treatment shows that got us into building the ovens.

The professionally made castings available now are just too "cheap" to justify the labor on my part, and they look so much nicer!

Click to expand...

I can't agree more about the aesthetics of the castings but I'm in the UK which makes shipping costs prohibitive. I expect if I bought a pallet of them off Richard and had then sent by sea the unit cost would come down. Perhaps I should become his European agent ! The lathe bed @ 5" depth was at the max we could cut with the 9" grinder but if see another bed come up cheap ….

I cut one end of a blank on the 6 x 4 bandsaw fitted with an M42 varitooth blade and it cut beautifully -I hope this bodes well for scraping.

Tray said:

Looking for some advice / thoughts on to make some straight edges from two blanks taken from an scrapped antique lathe. Both are just over 30” and 5” deep and are typically as per the images and approximately
dimensioned as per these sketches.


Blank A is a little wider at the base and the dovetail is currently 55° I thought this would give me a bit more meat to machine it to 45 °. The large rib along the top does not continue the full length.

I do not yet have a surface plate and am looking at 24” x 18” as being the max I probably need or can fit in my workshop. I may be able to stress relieve by heat treatment.

Here are my thoughts

1. As I neither need nor will be able to check a 30” I cut the ends @ 65° as shown by the blue lines – that way losing the section where there is no stiffening rib.
   
2. The stiffening rib is substantial @ 1 x 0.7" and offset so perhaps I can machine some of it away to lose weight.
   
3. Machine away the other bosses and clean up the vertical ribs
   
4. The vertical ribs will not be centred along the length so if no one says otherwise I’ll put a couple of lightening holes equidistant between them as per the sketch.
6. Perhaps for the other blank I could make an 18” and a 12”?

Am I correct in thinking that it will be easier for me to learn to scrape in the 12” first ?
I appreciate that these will never be Kingway camelbacks, but I have seen Youtubers make some nice straight edges from a similar starting point.

Click to expand...

It will work, I made one from a wood lathe bed. depending on the age and stability of the cast it may or may not move. Scrape it in let it sit and check it after a few months. I hang mine up and beat the crap out of it. If i were making one from that casting, I would remove more of the webbing to make it lighter.

edit:

maybe something like this...just make sure what remains is not too flimsy....




dee
;-D

Richard King said:

A longtime PM member Jan Sverre Haugjord who also has several You Tube shows on scraping cut up a wood lathe bed in 2015 and documented it on You Tube. He sold them to some of the students of the Danish scraping school. So I think you will be fine. The cast iron is aged if it's antique...how old is your lathe? I hope you make a thread showing all what your doing or a You Tube show. Sounds like a good read and watch! Poor man's straight edges - YouTube

PS: 1/2 Norwegian and 1/2 English...lol

He also makes some from an old lathe he found at a farm. LOL
Making straightedges.. again - part 1 - YouTube

Click to expand...

I have one of Jan Sverres and can not be more happy with it. So far it has been stable and not moved during my time (1,5yrs now). But surely different donor material may behave differently.
It´s one of the best things I broght home from class, together with the practice and know-how gained of course, as it has really been a good reference to look at and compare my continued training and practice efforts on my own.

dcsipo said:

It will work, I made one from a wood lathe bed. depending on the age and stability of the cast it may or may not move. Scrape it in let it sit and check it after a few months. I hang mine up and beat the crap out of it. If i were making one from that casting, I would remove more of the webbing to make it lighter.

edit:

maybe something like this...just make sure what remains is not too flimsy....

View attachment 234174


dee
;-D

Click to expand...

Thanks for the sketch I cut the ends and its coming @ 23lbs so some lightening would not go amiss …

I have one of Jan Sverres and can not be more happy with it. So far it has been stable and not moved during my time (1,5yrs now). But surely different donor material may behave differently.
It´s one of the best things I broght home from class, together with the practice and know-how gained of course, as it has really been a good reference to look at and compare my continued training and practice efforts on my own.

Click to expand...

That's really good to know. I think I could save some time on the learning process by investing in Richards scraping DVD.

The bevel edge I suggested 48 deg' rather than 50 or 55 or even 60. It is unlikely that you will come across a 45 degree dovetail to scrape - in the UK 50 & 55 degrees are typical for older machines. So 48 degrees covers those.

Sorry if my early post was not so clear.

There was a damaged SE on ebay recently - busted end off an 8ft. also damaged mid way along - the seller was asking silly money - but I suspect it could be had now as it didnt sell - it may provide you with a decent 48" all be it in an odd shape. It was over in Sheffield as I recall.

ATB mat

If your building a new machine and have to machine the ways on all the parts the same degree, then you would care what the degree is. When we rebuild machines we don't care and most cases a 45 deg. works. I make a small 12" 50 deg SE because on Monarch Lathe Compounds that are 50 degree, you can't tip the 45 deg angle up without hitting the clearance surface between the ways. That is the only place I have seen an issue. I suppose you could, have but in all that I have rebuilt / scraped in all my years it's not important in the majority of machines.

We do not scrape a dovetail and flat at same time. Take for instance a Bridgeport mill knew or table. You scrape the 2 flats first getting them flat and parallel to each other then you scrape the dovetails flat and parallel to each other. You set the 45 deg into the 50 degree and tip it up flat against the surfaces.

Making it an exact degree is not important. It might be 48, 49 1/2, 50, 51, etc. All you care about is it is flat and parallel and then you match fit the riding part or on the Bridgeport you match fit the saddle to the knee or table. You would waste so much time making it an exact degree. You could do it but you would be the first outside the factory who cares.

Lurk said:

The bevel edge I suggested 48 deg' rather than 50 or 55 or even 60. It is unlikely that you will come across a 45 degree dovetail to scrape - in the UK 50 & 55 degrees are typical for older machines. So 48 degrees covers those.

Sorry if my early post was not so clear.

There was a damaged SE on ebay recently - busted end off an 8ft. also damaged mid way along - the seller was asking silly money - but I suspect it could be had now as it didnt sell - it may provide you with a decent 48" all be it in an odd shape. It was over in Sheffield as I recall.

ATB mat

Click to expand...

Thanks for the clarification, its my lack of knowledge rather than your post. I have been looking on ebay but as you say prices are silly. My friend is into antiques he says they come up at fairs at better prices.

Anyway my SE will cost me little and I need to but a surface table / plate. I can machine a 48 or so out of the existing 55 degree, might be simplest to tilt (nod) the head on the mill.

Richard King said:

If your building a new machine and have to machine the ways on all the parts the same degree, then you would care what the degree is. When we rebuild machines we don't care and most cases a 45 deg. works. I make a small 12" 50 deg SE because on Monarch Lathe Compounds that are 50 degree, you can't tip the 45 deg angle up without hitting the clearance surface between the ways. That is the only place I have seen an issue. I suppose you could, have but in all that I have rebuilt / scraped in all my years it's not important in the majority of machines.

We do not scrape a dovetail and flat at same time. Take for instance a Bridgeport mill knew or table. You scrape the 2 flats first getting them flat and parallel to each other then you scrape the dovetails flat and parallel to each other. You set the 45 deg into the 50 degree and tip it up flat against the surfaces.

Making it an exact degree is not important. It might be 48, 49 1/2, 50, 51, etc. All you care about is it is flat and parallel and then you match fit the riding part or on the Bridgeport you match fit the saddle to the knee or table. You would waste so much time making it an exact degree. You could do it but you would be the first outside the factory who cares.

Click to expand...

Thanks for the clarification, I do need to cut a matching dovetail when I make my taper attachment but I'll only need a small 6" SE for that and will make it to suit the dovetail cutter I have. I'll go with Lurks suggestion for the 24"

Not offering but I can grind 31" to .0002 or so..Most any grind shop can do that..

You might be ahead to take it to a grind shop and have then rough it in to under or around .001-002 just to save your time.

Handy bargain
Granite Surface Plate 6" x 18" x 2" A Grade

Sometimes you might run into an oid perhaps scrap height gauge of 18 to 48" long.. that is good steel and can be made into a very nice straight edge.

michiganbuck said:

Not offering but I can grind 31" to .0002 or so..Most any grind shop can do that..

You might be ahead to take it to a grind shop and have then rough it in to under or around .001-002 just to save your time.

Handy bargain
Granite Surface Plate 6" x 18" x 2" A Grade

Sometimes you might run into an oid perhaps scrap height gauge of 18 to 48" long.. that is good steel and can be made into a very nice straight edge.

Click to expand...

Yes that is a good find but I'm in the UK. I can get a Grade 00 24 x 18" for but I'll need work out where I'm going to pur 200 lbs of granite .. I need to sell some stuff to make room.

Good thought on grinding, my friend can do 12" might be able to get close to what I need with a couple of bites at the cherry and careful set up.

long thin grinding can be a bugger..often to sacrifice surface finish to avoid burning warp. good to run wet and pause between passes.

Once you put a burn warp in steel it can retain a memory and then stress off with time..even with the burn removed.

Some long jobs I feed only on he grind side and count a few seconde before traveling back over.

a course open wheel (32-36) and full wheeling can be better in some cases.