Andy from Workshopshed
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I've never seen chipping like that from machining but given that the surface finish is top quality I'd not worry.
- Thread starter busastars
- Start date
Im nearly there with flycutting. I must point out that before Friday I never used a Mill in my life.
Now with the next bit of advice with reguards to cutting the squish band.
I will want to cut the Squish band about 10mm with 15 degree angle.
My thoughts is a small home made fly cutter with the cutting tool with a 10mm cut angled for the 15 degree cut. Basicly like one of those steppers / hole cutters but with only one step.
Second thought was a router cutter but turn the head on the rotary table set at the right angle for the 15 degree.
Some pics to show you what I mean:
Here is a head/squish already cut:
Standard head:
Pitted head:
A 250 head:
My collection of heads:
Now with the next bit of advice with reguards to cutting the squish band.
I will want to cut the Squish band about 10mm with 15 degree angle.
My thoughts is a small home made fly cutter with the cutting tool with a 10mm cut angled for the 15 degree cut. Basicly like one of those steppers / hole cutters but with only one step.
Second thought was a router cutter but turn the head on the rotary table set at the right angle for the 15 degree.
Some pics to show you what I mean:
Here is a head/squish already cut:
Standard head:
Pitted head:
A 250 head:
My collection of heads:
JimM
Member
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- 394
Just to throw something else into the mix, if you are looking for the best finish a number of people have had good results with this shaped cutter
http://madmodder.net/index.php?topic=850.0
Haven't tried it myself but will be when I need to do some fly cutting
Cheers
Jim
http://madmodder.net/index.php?topic=850.0
Haven't tried it myself but will be when I need to do some fly cutting
Cheers
Jim
Quite correct Jim did mention radius cutter earlier but reckon thats too good a finish.
Busa its starting to figure now and the need for a power feed. Every skimmed head i have ever seen factory or otherwise has not had a smooth finish, probably cut with one sharp edge at slow speed but enough to seal with a gasket.
Bring the barrels round, i'll do the porting.
One thing i have got to ask, is this a clean up job or a re engineered jobby? Either way a cheap vertical scale on the quill will prove very useful. ie skim head, zero readout and depth for combustion easilly read off and accurate.
Personally i would make two or three cutters, one for large area skimming, the others for chamber at correct angle- just line up and plunge in, job done.
Good machine for the job by the way just lock unused slides up.
While im at it i recommend strip the slides, jib strips and lead screws off and coat with that molecular stuff you warm up such as Fastex (R) It wont take long for play to show.
Busa its starting to figure now and the need for a power feed. Every skimmed head i have ever seen factory or otherwise has not had a smooth finish, probably cut with one sharp edge at slow speed but enough to seal with a gasket.
Bring the barrels round, i'll do the porting.
One thing i have got to ask, is this a clean up job or a re engineered jobby? Either way a cheap vertical scale on the quill will prove very useful. ie skim head, zero readout and depth for combustion easilly read off and accurate.
Personally i would make two or three cutters, one for large area skimming, the others for chamber at correct angle- just line up and plunge in, job done.
Good machine for the job by the way just lock unused slides up.
While im at it i recommend strip the slides, jib strips and lead screws off and coat with that molecular stuff you warm up such as Fastex (R) It wont take long for play to show.
Chears all, BChild keep hold of that head, give me a couple of weeks and ill have it off you.
hareng, chears for the offer fella but ive got my spair barrels already heavly ported and another set to play with after, not port timing though just opend up a fair old bit with a few little trick bits. Your right though, every machined head ive seen has had machine marks on them, also its for a little 2T, will be cutting O'ring groves around the cylinders so no gasket worries for me. My one set of barrels have been O'ringed and the head I have hear already machined will be for them.
The last bit lost me but im sure ill figure it out soon
Got to admit im quite chuffed to have been able to get such a good finish in a few attempts over a weekend.
hareng, chears for the offer fella but ive got my spair barrels already heavly ported and another set to play with after, not port timing though just opend up a fair old bit with a few little trick bits. Your right though, every machined head ive seen has had machine marks on them, also its for a little 2T, will be cutting O'ring groves around the cylinders so no gasket worries for me. My one set of barrels have been O'ringed and the head I have hear already machined will be for them.
The last bit lost me but im sure ill figure it out soon
Got to admit im quite chuffed to have been able to get such a good finish in a few attempts over a weekend.
Straight through the spark plug hole.
Pete.
Member
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- Kent, UK
I think the reason you have that flaking is because you have a tiny radius on the cutting part of the tip and it's shearing the material like a carbide tip does on steel rather than cutting it like HSS should.
You got a nice finish on there (just like carbide does on hard materials) but I defy you to re-grind the tool and repeat the finish.
You got a nice finish on there (just like carbide does on hard materials) but I defy you to re-grind the tool and repeat the finish.
brightspark
Member
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- yarm stockton on tees
using a disc sander with aluminium oxide disk .just set the angles and away u go easier if your not farmiliar with a grinder easier if u are as well 
Busa asked me this one in a pm as i don't always like to post certain things. This one i will answer here. Sorry Pete not trying to out do you here, more a case of others may also benefit in the future.
Whats happening is the quality of the sheer is varying along the cutting edge relative to the depth of cut. Lets say you are taking a cut of .010" or .25mm, In this case the tool has been ground by hand and is cutting correctly where it contacts the 'face' of the material/the new depth being cut in the material. This why you are still getting a good surface finish. Further up the cutting edge face it is not ground correctly hence a variable in the quality of the sheer. This is more likely a case of having several attempts to grind the tool and not getting one clean facet to do the cutting.
What will happen is something like this, you take a cut, the .25mm. The tool is ground correctly for say .2mm from the tip then the other .05 is not ground correctly. The tool is more than likely rubbing or cutting with a poor sheer. Hence you get this flake swarf appearing on top The tool is trying to push the material away as apposed to actually cutting. As its only a very small portion of the tool not cutting its not enough to really affect the cut and produce big roll overs of material and stop cutting completely. As you can tell, its a not a chip or a small string of swarf as you would expect. So its not cutting correctly in that area of the depth of cut.
You can see similar with carbide used in the right environment. As the tip goes 'off' they can generate powder swarf. The powder being small does not leave the machining area like normal swarf. So it stays there hanging about and literally wears the tool faces away, effectively like grinding compound, after a time the cutting edge becomes worn and the tool starts to scrape as its no longer the furthest point forward on the cutting edge.
I hope that made some sense of it.
Kind regards,
Scott (ward eng)
Well before I started I read on loads of posts on various forums and alot of people were struggling to get a good finish, like my first two attempts. So to get this good a finish on both the 3rd & better on the 4th attempt also never have used a Mill before im cuffed to beans.
All of you have been a great help but esp Scott, he has given me alot of his time and im very greatfull.
I know the ground tool is not 100%, im strugling because my bench grinder has been abused (all by me ) so the stones are not even. Im going to buy a hand oil stone to finish of the edges and get a good even finish on the tools.
Also got some square bar today so going to make two tools to hold my index cutters and try them to see what king of finish they give.
Also my Angle Grinder packed up the other day, £15 for three years abuse its just not fair, expacted five Went round every where to get a new el'cheapo one again and know where has one.
All of you have been a great help but esp Scott, he has given me alot of his time and im very greatfull.
I know the ground tool is not 100%, im strugling because my bench grinder has been abused (all by me
) so the stones are not even. Im going to buy a hand oil stone to finish of the edges and get a good even finish on the tools.Also got some square bar today so going to make two tools to hold my index cutters and try them to see what king of finish they give.
Also my Angle Grinder packed up the other day, £15 for three years abuse its just not fair, expacted five
Went round every where to get a new el'cheapo one again and know where has one.Depends upon the aluminium grade whether or not it comes off in chips.
Free cutting does but 6082 is more ductile and less resilient to the swarf breaking ala chips!
Work with 6082 all the time purely its better for anodising and freely available, downside it can clog the tools so no cnc.
Sharp tool with leave flakes in none free cutting, think this way. If tool is sharp and relief ok, the aluminium wont break it will bend, so usually ends up in coil or flakes which are wafer thin.
From 6082
http://pic20.picturetrail.com/VOL15/728921/1243581/388935710.jpg Drilled, counterbored and tapped in miller, not by hand for the other thread.
http://pic20.picturetrail.com/VOL15/728921/1243489/297909674.jpg
Action shot small chuck http://pic20.picturetrail.com/VOL15/728921/1252422/14577361.jpg
http://pic20.picturetrail.com/VOL15/728921/1252422/14582133.jpg
No coolant either, too close to chuck or get drounded.
Free cutting does but 6082 is more ductile and less resilient to the swarf breaking ala chips!
Work with 6082 all the time purely its better for anodising and freely available, downside it can clog the tools so no cnc.
Sharp tool with leave flakes in none free cutting, think this way. If tool is sharp and relief ok, the aluminium wont break it will bend, so usually ends up in coil or flakes which are wafer thin.
From 6082
http://pic20.picturetrail.com/VOL15/728921/1243581/388935710.jpg Drilled, counterbored and tapped in miller, not by hand for the other thread.
http://pic20.picturetrail.com/VOL15/728921/1243489/297909674.jpg
Action shot small chuck http://pic20.picturetrail.com/VOL15/728921/1252422/14577361.jpg
http://pic20.picturetrail.com/VOL15/728921/1252422/14582133.jpg
No coolant either, too close to chuck or get drounded.
Anyway back to one of my questions, only had one answer so far but apart from a small flycutter cutting a 10mm squish band in one go like a plunger into the chamber, is there an easyer or better way.
The chamber and O'ringing ive got sorted out, thats easy enough.
The chamber and O'ringing ive got sorted out, thats easy enough.
brookie456
Friar Amps
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- 190
As Scott and Hareng have advised, remember though aluminium is relatively soft, it is extremely abrasive to cutting tools - loose the edge and relief angles and it will drag, fold, smear etc. -sharp tool, parafinn and the other advise will help, but as Hareng said, unless you can hold it absolutely 100% rigid, no chance of a decent finish on a plunge cut.
Good advice, i cant stress that enough Brookie.
What will help a lot is once centred over point is to lock X and Y beds down and tension up Z feed so it will still wind down with handle, not as a drill. This will take the play out of the quill, believe me it will show if you dont.
Once it starts to chaff, theres no stopping it and any attempts to cure will make it worse.
That excludes the cutter shape, take your time get it right. If using HSS bit ground up go for the dearer Cobalt 5%, theres some real rubbish around usually from asia.
Just done something similar with excellent quality mill bit thats gone off, only drilled down 7.8mm 12mm dia holes, kept opening up from a 6mm dia. Guessed it, left chaff marks on the flat bottom and cylindrical sides but will covered up with bead blaster, not critical.
Have a practice and try and get a feel for the cutting.
What will help a lot is once centred over point is to lock X and Y beds down and tension up Z feed so it will still wind down with handle, not as a drill. This will take the play out of the quill, believe me it will show if you dont.
Once it starts to chaff, theres no stopping it and any attempts to cure will make it worse.
That excludes the cutter shape, take your time get it right. If using HSS bit ground up go for the dearer Cobalt 5%, theres some real rubbish around usually from asia.
Just done something similar with excellent quality mill bit thats gone off, only drilled down 7.8mm 12mm dia holes, kept opening up from a 6mm dia. Guessed it, left chaff marks on the flat bottom and cylindrical sides but will covered up with bead blaster, not critical.
Have a practice and try and get a feel for the cutting.
For a new Flycutter I have two thoughts:
1st Thought is I have my original and the head is screwed onto the MT3 shaft, Ive sent an email to Chronos asking if they sell smaller heads for that cutter as it came from them.
2nd Thought is to make a simple right angle flycutter holder (dog leg / 90 degree) so the tool is held square and just cut the shape of the tool to the right angle of the squish.
I know to alot of people this is alot of effot for not alot of reward but for me this is the start of my foundation for getting more involved with machining and somthing that im very intrested in (as in 2T Tuning)
Ops forgot to say I do have a Buret, start of my little scince lab and foundations to take over the world ( as said by Pinky & the Brain )
1st Thought is I have my original and the head is screwed onto the MT3 shaft, Ive sent an email to Chronos asking if they sell smaller heads for that cutter as it came from them.
2nd Thought is to make a simple right angle flycutter holder (dog leg / 90 degree) so the tool is held square and just cut the shape of the tool to the right angle of the squish.
I know to alot of people this is alot of effot for not alot of reward but for me this is the start of my foundation for getting more involved with machining and somthing that im very intrested in (as in 2T Tuning)
Ops forgot to say I do have a Buret, start of my little scince lab and foundations to take over the world ( as said by Pinky & the Brain )
