Author Topic: A thing..... (Read 43345 times)

bogstandard · « **Reply #50 on:** September 10, 2009, 04:00:11 AM »

You're right Nick.

You will find that when using one of these, you give your tooling a couple of extra degrees all round, just to make up for it. Or else, put a bit of packing underneath, but that isn't as critical as trying to shim for correct height, just a matter of raising the tool a bit.

Bogs

John Stevenson · « **Reply #51 on:** September 10, 2009, 04:17:37 AM »

Here's one I did originally in the 1980's

http://www.metalwebnews.com/howto/toolpost/toolpost.html

This was done because at that time there were no cheap imports and the only one available was the Myford Dickinson one which was too expensive for me at the time.

It wasn't a copy of anything and a clean sheet design, compared to modern posts the dovetails are inverted. This was done purposely as I wanted the holders to be easy to make going along the lines of you need more holders than posts.

The holders were made in strips on a horizontal mill with a 60 degree angles cutter at night school in 18" lengths and cut off as needed.
That particular post and the 17 ? odd holders have long gone but I still use a slightly scaled up version on my lathes today.
I have three nearly identical posts and about 50 holders what swap between 3 lathes.

Would I do the same today ?
Probably not as it's cheaper to buy these items but sometimes it's not about buying / obtaining. most of my early equipment like rotary tables, dividing heads, morse taper arbors and even a Dore Westbury milling machine were made in my workshop.
The experience of doing this is priceless.

John S.

NickG · « **Reply #52 on:** September 10, 2009, 07:02:32 AM »

Good stuff John S, the type I want is circa £100 so if I could make one for nothing it would be good, however, it'd be a pretty sizeable project for me and the limited time I get in the workshop.

I used to have a dore-westbury but unfortunately it wasn't a particularly well made example. When I was younger, I also bought a Centec 2A mill (great quality machine), I intended to fit the vertical head from my dore-westbury onto it but as it wasn't too clever it wasn't worth it so bought a new mill. I got the milling machine from an auction, but bizzarely, it belonged to an, unfortunately, deceased member of our club. He had a dore-westbury vertical head ready converted but donated that to the club. I offered the club good money for it as it was a good one, but they declined saying it was useful to train people up on rather than the big beast of a warco thing!

Nick

raynerd · « **Reply #53 on:** September 10, 2009, 04:25:31 PM »

Well guys - it is a start! I`ve hacked a piece off the end of my steel bar and all is looking good. The chop saw went through it pretty easily, took about 3 minutes to get to half way at which point I let it cool for 30 minutes then went back to finish it off. Clean cut just not perfectly straight but I soon rectified that by facing the end up roughly in the lathe. However, not using the chop saw before, I cut about 0.25" over size to give me some play and basically I have this on the block so I`m going to have to take it off in the lathe - that could take a while! So next job is to face up the end and bring to size and then drill the bore for the off centre cam. I just need to have a think about sizes and also whether I need to drill it off centre like Darren did. I`m not to sure that if I just drill it centre that I`ll have enough clearence anyway. I guess I need to face up and then have a good mark out and think....

Anyway, tiz a start!

First picture shows the bar and also the block that I intially found and was going to use. I choose the bar in the end because the block didn`t give me enough height.

Darren · « **Reply #54 on:** September 10, 2009, 05:28:45 PM »

Beats handsawing dunit.....did the saw complain or the blade grab at all? It looks like it cut fairly well without too much burning evidence......nice one

I suspect that is not hardened steel which you will be o-so-grateful for.....

NickG · « **Reply #55 on:** September 10, 2009, 07:14:58 PM »

Good stuff Chris, I will be watching and hopefully learning as my 1 way tool post is annoying me so much I'm very tempted to make this my next project now!

raynerd · « **Reply #56 on:** September 12, 2009, 04:57:45 PM »

Got a little more done today and all thanks to my new 2 1/2 end mill cutter! Cuts the stuff like butter and with a 90deg side, it also allowed me to do up to a square side ready for the dovetails:

I have put a first drill down it but couldn`t go further since I need a 5/8" drill. Since it being perfectly central is not critical, I`ll be able to set this back up on the lathe for the centre drill and bore.

Anyway - massive problems now since I purchased a 45deg dovetail cutter but it doesn`t seem to want to cut for me! It just screams. I`ve tried changing the speeds and nothing. It is making a cut but really really slowly and a terrible sound. Any adivce?

Chris

Darren · « **Reply #57 on:** September 12, 2009, 05:02:41 PM »

Quote from: craynerd on September 12, 2009, 04:57:45 PM

Anyway - massive problems now since I purchased a 45deg dovetail cutter but it doesn`t seem to want to cut for me! It just screams. I`ve tried changing the speeds and nothing. It is making a cut but really really slowly and a terrible sound. Any adivce?

Chris

Use your shaper........

Sorry, couldn't resist.....but shapers do make dovetails rather easily.

Never used a dovetail cutter on the mill, but it sounds like you might be tickling it at too high a speed? I'm just guessing, wait for someone who might actually know something to come along.....

You need to remove as much material as you can before using the dovetail cutter, I can tell you that much.

bogstandard · « **Reply #58 on:** September 12, 2009, 05:20:08 PM »

A dovetail cutter is a very fragile toobit. By the sounds of it, you have already done it fatal damage.

You need very fine feeds and lots of coolant and lube.

I made a new topslide for a lathe last year out of gauge plate, which I am sure is just as tough as the stuff you are using, but because of the way the cutter was treated, it is still as good as brand new, and will be used again when I make some tooling for my lathe.

Sounds like a very expensive mistake to me.

You can use a flycutter to make external dovetails fairly easily, but you need to be able to grind the tool accurately. In fact, when I come to cut mine, I will most probably use a flycutter for most of the rough metal removal, and save the precious dovetail cutter for final finishing.

Bogs

raynerd · « **Reply #59 on:** September 12, 2009, 06:19:12 PM »

Humm, thanks for the reply John. That is good idea, so basically grind up some HSS perhaps just short of 45deg and use that as a single point cutting tool in the flycutter. Then use the dovetail to finish the job after the bulk of the material has been removed by the flycutter.
I could possibly have damaged my dovetail cutter but it seems fine enough, still as sharp as before and no noticable damage. I didn`t use it for very long, only a minute before I realised I was rushing and decided to leave while I found some more info. Will have to see if I have spoilt it but I guess not....

I`ll give the flycutter method a go and I guess the cutter shape would be just less than 45deg to allow the finish to be put on with the dovetail cutter.

Thanks for the suggestion. I`ll let you know how I get on tomorrow.

Darren - I really wanted to use my shaper for the dovetails but I`m still having issues. I`ve smashed a piece of the pully trying to remove it from the shaft - it has all siezed up and I think I hit it a bit hard

. Now I need to drill a hole for some brackets and then mount it but it is getting around to doing it. If I`m being honest, it is the only bit of kit that isn`t here at my house, it is at my grandparents as I don`t have any room for it here (it won`t fit in the cellar), consequently I don`t get much time to work on it, or at least I have to make more of an effort. I hope to have it running in the next few weeks, although I said that a month ago!

Chris

NickG · « **Reply #60 on:** September 14, 2009, 11:58:00 AM »

Chris,

Even if the flycutter works for the tool post, will you be able to get in to do the holders with the fly cutter?

Nick

raynerd · « **Reply #61 on:** September 14, 2009, 01:07:57 PM »

Tiz a good point Nick. I`ve just seen Stews post on his gauge he is making and he used a boring bar style tool in effect to fly cut the material out.

If you look back to the original post that Darren got his inspiration from, after taking out the main channel with a end mill he then took the entire dovetail cut with the dovetail cutter. I appreciate they are delicate but I have seen them used progressively to take the entire cut. No doubt if you removed some of the material first with a profiled fly cutter they would save the life of the dovetail cutter but I`m sure it should be able to do the entire cut. Think I need to use more coolant and a slower feed.....

raynerd · « **Reply #62 on:** September 14, 2009, 01:09:25 PM »

...also reading the other thread on QCTP`s and I wish I`d read Darrens advice earlier regarding doing the dovetails first - If I mess these up then the whole thing is scrapped and I`ve since spent much more time boring out the centre

NickG · « **Reply #63 on:** September 14, 2009, 01:51:00 PM »

It'll be ok, just take a step back and be patient. The amount of parts I ruin because I get over confident and take bigger cuts to hurry things up ... I'm getting better though.

Nick

DICKEYBIRD · « **Reply #64 on:** September 17, 2009, 09:40:34 AM »

I envy you fellows with shapers. Not having one, I made a dovetail cutter with a carbide insert and it works pretty well. You still have to go fairly slow but we have lots of time in the home shop, right?

It's made from (what we call over here in the states) 4140 pre-hard.

Darren · « **Reply #65 on:** September 17, 2009, 09:47:12 AM »

I had considered making one of those tools, what are you cutting...alloy?

How is it with steel?

DICKEYBIRD · « **Reply #66 on:** September 17, 2009, 10:25:26 AM »

Yup, that was 2024 aluminum in the pic but it cuts steel & cast pretty well too. Just as in other cutting tools, you have to back down the speed & depth of cut appropriately.

One of these days when I have my audience with the Wizard of Oz and get a brain, I'll actually learn how to compute SFM properly and know I have it right.

NickG · « **Reply #67 on:** September 17, 2009, 01:30:40 PM »

Looks fantastic that cutter.

Darren · « **Reply #68 on:** September 17, 2009, 02:05:04 PM »

Good to know it works......

Thanks for posting, gives me more reason to make one now...

DICKEYBIRD · « **Reply #69 on:** September 17, 2009, 02:32:30 PM »

I finally remembered the website where the inspiration to build my dovetail cutter came from: http://www.gadgetbuilder.com/ToolHolders.html John Moran's a clever fellow and makes neat tools from whatever he's able to find lying around.

Another example here: http://www.cnccookbook.com/MTMillDovetail.htm

NickG · « **Reply #70 on:** September 18, 2009, 04:41:11 AM »

Some clever stuff on that first website!

crazypj · « **Reply #71 on:** February 18, 2015, 10:10:04 PM »

This just turned up on Homemadetools.net
Didn't realise it was made 2009
Anyway, the original material looks like a bucket pin from a large excavator.

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Author Topic: A thing..... (Read 43345 times)

bogstandard

bogstandard