Polishing compression chamber with flap wheel

[pratik_mahale]

Recently I brought a mini bench grinder with flexible shaft & I thought of using this shaft to polish the compression chamber of my IHP 35 so I made three flap wheels with 80,120 & 400 grit sanding paper

DIY Flap Wheel -1.jpg

First I cut 5 strips of Sanding paper 4 cm long
Pasted it on dremel sanding band in clock wise direction

Then I polished my IHP 35 compression chamber first with 80 then 120 & finally with 400 grit flap wheel

DIY Flap Wheel -2.jpg

I also carefully polished the trigger with my DIY Belt Sander & now the trigger pull is around 1.5 Kg

Here is a link for making a simpler flap wheel for drill machine
http://www.instructables.com/id/Make-yo ... lap-wheel/

[brihacharan]

Recently I brought a mini bench grinder with flexible shaft & I thought of using this shaft to polish the compression chamber of my IHP 35 so I made three flap wheels with 80,120 & 400 grit sanding paper

DIY Flap Wheel -1.jpg

First I cut 5 strips of Sanding paper 4 cm long
Pasted it on dremel sanding band in clock wise direction

Then I polished my IHP 35 compression chamber first with 80 then 120 & finally with 400 grit flap wheel

DIY Flap Wheel -2.jpg

I also carefully polished the trigger with my DIY Belt Sander & now the trigger pull is around 1.5 Kg

Here is a link for making a simpler flap wheel for drill machine
http://www.instructables.com/id/Make-yo ... lap-wheel/

Hi Pratik,
> Excellent & innovative adaptation on a flexible shaft for internal grinding / polishing & buffing
> But remember that "Too Smooth" an internal of a receiver is not preferable - The reason being the surface will not retain lube for longer periods.
> What is required is "Uniformity" of bore all throughout - A 200 grit is ideal as this leave very tiny crevices within which the lube gets retained + the flexibility of the synthetic seal will adapt itself to these = result increase in compression efficiency
> Well done!!!!
Briha

[Basu]

Good idea !!
I think cloth grit can only withstand the high RPM.
I am very keen to know the result.

Basu

[airgun_novice]

Dear Pratik,
Please be careful when you polish the trigger innards. You do not want the sear to be too smooth. You should get the Innovator of the Month Award.
regs
A.

[pratik_mahale]

Dear Pratik,
Please be careful when you polish the trigger innards. You do not want the sear to be too smooth. You should get the Innovator of the Month Award.
regs
A.

Thanks AGN

Baus you are right

[bennedose]

Pratik Mahale you are giving me ideas.

If you buff out the inside of the compression chamber by 0.6 to 1 mm (0.3 to 0.5 mm all around), the internal volume of the chamber may increase by about 5-8% assuming a stroke volume of 54 cc. That could give a significant increase in power - although the piston would have a lot of play. Perhaps the play could be controlled by suitably sized rings.

[brihacharan]

Dear Pratik,
Please be careful when you polish the trigger innards. You do not want the sear to be too smooth. You should get the Innovator of the Month Award.
regs
A.

> Too smooth trigger sears can cause AUTO FIRE which is "Dangerous" especially in springers - where the pressure of the compressed spring directly rests on the trigger sear - Whereas in PCPs its on the Valve which needs only very little pressure to open it to let the stored compressed air pass through the transfer port.
> AGN - thanks for putting it so succinctly
Briha

[sa_ali]

excellent DIY for internal polisher

[sathya.sniper]

Pratik Mahale you are giving me ideas.

If you buff out the inside of the compression chamber by 0.6 to 1 mm (0.3 to 0.5 mm all around), the internal volume of the chamber may increase by about 5-8% assuming a stroke volume of 54 cc. That could give a significant increase in power - although the piston would have a lot of play. Perhaps the play could be controlled by suitably sized rings.

i have small doubt regarding this function, If we need to add a ring to the side of the piston we might need a slit/a small place machined on the piston inorder to fit the O-ring around the piston but in our IHP piston there is not much thickness for making a slit for adding a Oring isnt it I think the piston must be thicker.
Is my question right ?

-Sathya

[moulindu]

Hi
Good work Pratikji, I tried a similar job of polishing the compression chamber using a hand drill. I installed a stick(as spindle) & paste a 200 grit sand paper on the end of it. But i was concerned with the centering of the spindle as non centered spindle will non-uniformly polish the compression chamber which may be more harmful.
Regards Moulindu